ADIS16475 Datasheet by Analog Devices Inc.

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ANALOG DEVICES
Precision, Miniature MEMs IMU
Data Sheet ADIS16475
Rev. C Document Feedback
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FEATURES
Triaxial, digital gyroscope
±125°/sec, ±500°/sec, ±2000°/sec range models
2°/hr in-run bias stability (ADIS16475-1)
0.15°/√hr angle random walk (ADIS16475-1 and
ADIS16475-2)
±0.1° axis to axis misalignment error
Triaxial, digital accelerometer, ±8 g
3.6 μg in-run bias stability
Triaxial, delta angle and delta velocity outputs
Factory calibrated sensitivity, bias, and axial alignment
Calibration temperature range: −40°C to +85°C
SPI compatible data communications
Programmable operation and control
Automatic and manual bias correction controls
Data ready indicator for synchronous data acquisition
External sync modes: direct, pulse, scaled, and output
On demand self test of inertial sensors
On demand self test of flash memory
Single-supply operation (VDD): 3.0 V to 3.6 V
2000 g mechanical shock survivability
Operating temperature range: −40°C to +105°C
APPLICATIONS
Navigation, stabilization, and instrumentation
Unmanned and autonomous vehicles
Smart agriculture and construction machinery
Factory/industrial automation, robotics
Virtual/augmented reality
Internet of Moving Things
GENERAL DESCRIPTION
The ADIS16475 is a precision, miniature MEMS inertial measure-
ment unit (IMU) that includes a triaxial gyroscope and a triaxial
accelerometer. Each inertial sensor in the ADIS16475 combines
with signal conditioning that optimizes dynamic performance.
The factory calibration characterizes each sensor for sensitivity,
bias, alignment, linear acceleration (gyroscope bias), and point
of percussion (accelerometer location). As a result, each sensor
has dynamic compensation formulas that provide accurate
sensor measurements over a broad set of conditions.
The ADIS16475 provides a simple, cost effective method for
integrating accurate, multiaxis inertial sensing into industrial
systems, especially when compared with the complexity and
investment associated with discrete designs. All necessary motion
testing and calibration are part of the production process at the
factory, greatly reducing system integration time. Tight orthogonal
alignment simplifies inertial frame alignment in navigation
systems. The serial peripheral interface (SPI) and register
structure provide a simple interface for data collection and
configuration control.
The ADIS16475 is available in a 44-ball, ball grid array (BGA)
package that is approximately 11 mm × 15 mm × 11 mm.
FUNCTIONAL BLOCK DIAGRAM
CONTROLLER
POWER
MANAGEMENT
CS
SCLK
DIN
DOUT
GND
VDD
DR
SYNC
RST
SPI
SELF TEST I/O
OUTPUT
DATA
REGISTERS
USER
CONTROL
REGISTERS
CALIBRATION
AND
FILTERS
ADIS16475
CLOCK
15436-001
TRIAXIAL
GYROSCOPE
TEMPERATURE
SENSOR
TRIAXIAL
ACCELEROMETER
Figure 1.
ADIS16475 Data Sheet
Rev. C | Page 2 of 37
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Timing Specifications .................................................................. 5
Absolute Maximum Ratings ....................................................... 7
Thermal Resistance ...................................................................... 7
ESD Caution .................................................................................. 7
Pin Configuration and Function Descriptions ............................. 8
Typical Performance Characteristics ........................................... 10
Theory of Operation ...................................................................... 12
Introduction ................................................................................ 12
Inertial Sensor Signal Chain ..................................................... 12
Register Structure ....................................................................... 13
Serial Peripheral Interface (SPI) ............................................... 14
Data Ready (DR) ........................................................................ 14
Reading Sensor Data .................................................................. 15
Device Configuration ................................................................ 16
User Register Memory Map .......................................................... 17
User Register Defintions ................................................................ 19
Gyroscope Data .......................................................................... 19
Delta Angles ................................................................................ 22
Delta Velocity .............................................................................. 23
Calibration ................................................................................... 25
Applications Information .............................................................. 32
Assembly and Handling Tips .................................................... 32
Power Supply Considerations ................................................... 33
Serial Port Operation ................................................................. 33
Digital Resolution of Gyroscopes and Accelerometers ......... 33
Evaluation Tools ......................................................................... 34
Tray Drawing .............................................................................. 36
Packaging and Ordering Information ......................................... 37
Outline Dimensions ................................................................... 37
Ordering Guide .......................................................................... 37
REVISION HISTORY
4/2019—Rev. B to Rev. C
Changes to Serial Peripheral Interface (SPI) Section ................. 14
Changes to Figure 32 ...................................................................... 15
Changes to Table 10 and Gyroscope Data Section ..................... 19
Changes to Acceleration Data Section ......................................... 20
Added Accelerometer Data Formatting Section ........................ 21
Deleted Accelerometer Resolution Section ................................. 21
Added Serial Port Operation Section, Maximum Throughput
Section, Serial Port SCLK Underrun/Overrun Conditions Section,
and Digital Resolution of Gyroscopes and Accelerometers Section
..................................................................................................................... 33
Moved Gyroscope Data Width (Digital Resolution) Section ... 33
Moved Accelerometer Data Width (Digital Resolution) Section .. 33
Moved Figure 52 and Figure 53 .................................................... 35
Added Tray Drawing Section ........................................................ 36
Added Figure 54 .............................................................................. 36
1/2019—Rev. A to Rev. B
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 5
Changes to Figure 5 .......................................................................... 6
Changes to Figure 11 ...................................................................... 10
Added Figure 12 and Figure 13; Renumbered Sequentially ..... 10
Added Figure 14, Figure 15, Figure 16, and Figure 17 .............. 11
Changes to Figure 18, Figure 19, and Figure 20 ......................... 12
Changes to Figure 22 and Figure 23............................................. 13
Added Gyroscope Data Width (Digital Resolution) Section ... 19
Changes to Gyroscope Measurement Range/Scale Factor Section,
Table 11, Table 12, Table 13, Table 17, Table 21, and Table 25 ... 20
Added Accelerometer Data Width (Digital Resolution)
Sec tion .............................................................................................. 21
Change to Calibration, Accelerometer Bias (XA_BIAS_LOW
and XA_BIAS_HIGH) Section ..................................................... 26
Change to Filter Control Register (FILT_CTRL) Section ......... 27
Changes to Direct Sync Mode Section and to Pulse Sync Mode
Sec tion .............................................................................................. 28
Changes to Sensor Self Test Section ............................................. 30
11/2017—Rev. 0 to Rev. A
Changes to Table 1 ............................................................................. 3
Deleted Endnote 1, Table 1; Renumbered Sequentially ............... 4
Added Endnote 2, Table 1; Renumbered Sequentially ................. 4
10/2017—Revision 0: Initial Version
Data Sheet ADIS16475
Rev. C | Page 3 of 37
SPECIFICATIONS
Case temperature (TC) = 25°C, VDD = 3.3 V, angular rate = 0°/sec, dynamic range = ±2000°/sec ± 1 g, unless otherwise noted.
Table 1.
Parameter Test Conditions/Comments Min Typ Max Unit
GYROSCOPES
Dynamic Range ADIS16475-1 ±125 °/sec
ADIS16475-2 ±500 °/sec
ADIS16475-3 ±2000 °/sec
Sensitivity ADIS16475-1, 16-bit 160 LSB/°/sec
ADIS16475-2, 16-bit 40 LSB/°/sec
ADIS16475-3, 16-bit 10 LSB/°/sec
ADIS16475-1, 32-bit 10,485,760 LSB/°/sec
ADIS16475-2, 32-bit 2,621,440 LSB/°/sec
ADIS16475-3, 32-bit 655,360 LSB/°/sec
Error over Temperature −40°C ≤ TC ≤ +85°C, 1 σ ±0.3 %
Repeatability1 −40°C TC ≤ +85°C, 1 σ ±0.3 %
Misalignment Error Axis to axis, −40°C ≤ TC ≤ +85°C, 1 σ ±0.1 Degrees
Nonlinearity2 ADIS16475-1, full scale (FS) = 125°/sec 0.2 % FS
ADIS16475-2, FS = 500°/sec 0.2 % FS
ADIS16475-3, FS = 2000°/sec 0.25 % FS
Bias
Repeatability1 −40°C TC ≤ +85°C, 1 σ 0.7 °/sec
In-Run Bias Stability ADIS16475-1, 1 σ 2 °/hr
ADIS16475-2, 1 σ 2.5 °/hr
ADIS16475-3, 1 σ 7 °/hr
Angular Random Walk ADIS16475-1, 1 σ 0.15 °/√hr
ADIS16475-2, 1 σ 0.15 °/√hr
ADIS16475-3, 1 σ 0.3 °/√hr
Error over Temperature −40°C ≤ TC ≤ +85°C, 1 σ ±0.2 °/sec
Linear Acceleration Effect Any direction, 1 σ 0.01 °/sec/g
Vibration Rectified Error (VRE) Random vibration, 2 grms, 50 Hz to 2 kHz 0.0005 °/sec/g2
Output Noise ADIS16475-1, 1 σ, no filtering 0.07 °/sec rms
ADIS16475-2, 1 σ, no filtering 0.08 °/sec rms
ADIS16475-3, 1 σ, no filtering 0.17 °/sec rms
Rate Noise Density ADIS16475-1, f = 10 Hz to 40 Hz 0.003 °/sec/√Hz rms
ADIS16475-2, f = 10 Hz to 40 Hz 0.003 °/sec/√Hz rms
ADIS16475-3, f = 10 Hz to 40 Hz 0.007 °/sec/√Hz rms
3 dB Bandwidth 550 Hz
Sensor Resonant Frequency 66 kHz
ACCELEROMETERS3 Each axis
Dynamic Range ±8 g
Sensitivity 32-bit data format 262,144,000 LSB/g
Error over temperature −40°C ≤ TC ≤ +85°C, 1 σ ±0.1 %
Repeatability1 −40°C TC ≤ +85°C, 1 σ ±0.1 %
Misalignment Error Axis to axis, −40°C ≤ TC ≤ +85°C, 1 σ ±0.05 Degrees
Nonlinearity Best fit straight line, ±2 g 0.25 % FS
Best fit straight line, ±8 g, x-axis 0.5 % FS
Best fit straight line, ±8 g, y-axis and z-axis 1.5 % FS
Bias
Repeatability1 −40°C TC ≤ +85°C, 1 σ 1.4 mg
In-Run Bias Stability 1 σ 3.6 g
Velocity Random Walk 1 σ 0.012 m/sec/√hr
Error over Temperature −40°C ≤ TC ≤ +85°C, 1 σ ±1 mg
Thesflm
ADIS16475 Data Sheet
Rev. C | Page 4 of 37
Parameter Test Conditions/Comments Min Typ Max Unit
Output Noise No filtering 0.6 mg rms
Noise Density f = 10 Hz to 40 Hz, no filtering 23 g/√Hz rms
3 dB Bandwidth 600 Hz
Sensor Resonant Frequency Y-axis and z-axis 2.4 kHz
X-axis 2.2 kHz
TEMPERATURE SENSOR
Scale Factor Output = 0x0000 at 0°C (±5°C) 0.1 °C/LSB
LOGIC INPUTS4
Input Voltage
High, VIH 2.0 V
Low, VIL 0.8 V
RST Pulse Width 1 µs
CS Wake-Up Pulse Width 20 µs
Input Current
Logic 1, IIH V
IH = 3.3 V 10 µA
Logic 0, IIL V
IL = 0 V
All Pins Except RST 10 µA
RST Pin 0.33 mA
Input Capacitance, CIN 10 pF
DIGITAL OUTPUTS
Output Voltage
High, VOH I
SOURCE = 0.5 mA 2.4 V
Low, VOL I
SINK = 2.0 mA 0.4 V
FLASH MEMORY Endurance5 10000 Cycles
Data Retention6 T
J = 85°C 20 Years
FUNCTIONAL TIMES7 Time until data is available
Power-On Start-Up Time 252 ms
Reset Recovery Time8 GLOB_CMD, Bit 7 = 1 (see Table 113) 193 ms
Factory Calibration Restore GLOB_CMD, Bit 1 = 1 (see Table 113) 142 ms
Flash Memory Backup GLOB_CMD, Bit 3 = 1 (see Table 113) 72 ms
Flash Memory Test Time GLOB_CMD, Bit 4 = 1 (see Table 113) 32 ms
Self Test Time9 GLOB_CMD, Bit 2 = 1 (see Table 113) 14 ms
CONVERSION RATE 2000 SPS
Initial Clock Accuracy 3 %
Sync Input Clock 1.9 2.1 kHz
POWER SUPPLY, VDD Operating voltage range 3.0 3.6 V
Power Supply Current10 Normal mode, VDD = 3.3 V 44 55 mA
1 Bias repeatability provides an estimate for long-term drift in the bias, as observed during 500 hours of high temperature operating life (HTOL) at 105°C.
2 This measurement is based on the deviation from a best fit linear model.
3 All specifications associated with the accelerometers relate to the full-scale range of ±8 g, unless otherwise noted.
4 The digital input/output signals use a 3.3 V system.
5 Endurance is qualified as per JEDEC Standard 22, Method A117, measured at −40°C, +25°C, +85°C, and +125°C.
6 The data retention specification assumes a junction temperature (TJ) of 85°C per JEDEC Standard 22, Method A117. Data retention lifetime decreases with TJ.
7 These times do not include thermal settling and internal filter response times, which may affect overall accuracy.
8 The RST line must be in a low state for at least 10 s to ensure a proper reset initiation and recovery.
9 The self test time can extend when using external clock rates lower than 2000 Hz.
10 Power supply current transients can reach 100 mA during initial startup or reset recovery.
#‘ H +‘ \‘
Data Sheet ADIS16475
Rev. C | Page 5 of 37
TIMING SPECIFICATIONS
TA = 25°C, VDD = 3.3 V, unless otherwise noted.
Table 2.
Parameter Description
Normal Mode Burst Read Mode
Unit Min Typ Max Min1 Typ Max
fSCLK Serial clock 0.1 2 0.1 1 MHz
tSTALL Stall period between data 16 N/A µs
tREADRATE Read rate 24 µs
tCS Chip select to SCLK edge 200 200 ns
tDAV DOUT valid after SCLK edge 25 25 ns
tDSU DIN setup time before SCLK rising edge 25 25 ns
tDHD DIN hold time after SCLK rising edge 50 50 ns
tSCLKR, tSCLKF SCLK rise/fall times 5 12.5 5 12.5 ns
tDR, tDF DOUT rise/fall times 5 12.5 5 12.5 ns
tSFS CS high after SCLK edge 0 0 ns
t1 Input sync positive pulse width; pulse sync mode, MSC_CTRL =
101 (binary, see Table 105)
5 5 µs
tSTDR Input sync to data ready valid transition
Direct sync mode, MSC_CTRL = 001 (binary, see Table 105) 256 256 µs
Pulse sync mode, MSC_CTRL = 101 (binary, see Table 105) 256 256 µs
tNV Data invalid time 20 20 µs
t2 Input sync period2 477 477 µs
1 N/A means not applicable.
2 This specification is rounded up from the cycle time that comes from the maximum input clock frequency (2100 Hz).
Timing Diagrams
CS
SCLK
DOUT
DIN
1 2 3 4 5 6 15 16
R/W A5A6 A4 A3 A2 D2
MSB DB14
D1 LSB
DB13 DB12 DB10DB11 DB2 LSBDB1
t
CS
t
DR
t
SFS
t
DF
t
DAV
t
SCLKR
t
SCLKF
t
DHD
t
DSU
15436-002
Figure 2. SPI Timing and Sequence Diagram
CS
SCLK
t
STALL
t
READRATE
15436-003
Figure 3. Stall Time and Data Rate Timing Diagram
ADIS16475 Data Sheet
Rev. C | Page 6 of 37
SYNC
DR
t
1
t
2
t
NV
t
STDR
15436-004
Figure 4. Input Clock Timing Diagram, Pulse Sync Mode, Register MSC_CTRL, Bits[4:2] = 101 (Binary)
SYNC
DR
t
2
t
NV
t
STDR
t
1
15436-005
Figure 5. Input Clock Timing Diagram, Direct Sync Mode, Register MSC_CTRL, Bits[4:2] = 001 (Binary)
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Data Sheet ADIS16475
Rev. C | Page 7 of 37
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Mechanical Shock Survivability
Any Axis, Unpowered 2000 g
Any Axis, Powered 2000 g
VDD to GND −0.3 V to +3.6 V
Digital Input Voltage to GND −0.3 V to VDD + 0.2 V
Digital Output Voltage to GND −0.3 V to VDD + 0.2 V
Calibration Temperature Range −40°C to +85°C
Operating Temperature Range −40°C to +105°C
Storage Temperature Range1 −65°C to +150°C
Barometric Pressure 2 bar
1 Extended exposure to temperatures that are lower than −20°C or higher
than +85°C can adversely affect the accuracy of the factory calibration.
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
THERMAL RESISTANCE
Thermal performance is directly linked to printed circuit board
(PCB) design and operating environment. Careful attention to
PCB thermal design is required.
The ADIS16475 is a multichip module that includes many
active components. The values in Table 4 identify the thermal
response of the hottest component inside of the ADIS16475,
with respect to the overall power dissipation of the module.
This approach enables a simple method for predicting the
temperature of the hottest junction, based on either ambient or
case temperature.
For example, when the ambient temperature is 70°C, the hottest
junction temperature (TJ) inside of the ADIS16475 is 76.7°C.
TJ = θJA × VDD × IDD + 70°C
TJ = 158.2°C/W × 3.3 V × 0.044 A + 70°C
TJ = 93°C
Table 4. Package Characteristics
Package Type θJA1 θ
JC2 Device Weight
ML-44-13 158.2°C/W 106.1°C/W 1.3 g
1 θJA is the natural convection junction to ambient thermal resistance
measured in a one cubic foot sealed enclosure.
2 θJC is the junction to case thermal resistance.
3 Thermal impedance values come from direct observation of the hottest
temperature inside of the ADIS16475 when it is attached to an FR4-08 PCB
that has two metal layers and has a thickness of 0.063 inches.
ESD CAUTION
00000000 0 0 O O 0 0000000 0 0 0000000 0 O O O 0 000000
ADIS16475 Data Sheet
Rev. C | Page 8 of 37
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
A
1
BCDEFGH J
2
3
4
5
6
7
8
K
15436-006
BOTTOM VIEW OF PACKAGE
ADIS16475
Figure 6. Pin Assignments, Bottom View
PIN A8
PIN A1
PIN K8
15436-007
Figure 7. Pin Assignments, Package Level View
Table 5. Pin Function Descriptions
Pin No. Mnemonic Type Description
A1 GND Supply Power Ground
A2 GND Supply Power Ground
A3 GND Supply Power Ground
A4 GND Supply Power Ground
A5 GND Supply Power Ground
A6 GND Supply Power Ground
A7 GND Supply Power Ground
A8 GND Supply Power Ground
B3 GND Supply Power Ground
B4 GND Supply Power Ground
B5 GND Supply Power Ground
B6 GND Supply Power Ground
C2 GND Supply Power Ground
C3 DNC Not applicable Do Not Connect
C6 GND Supply Power Ground
C7 VDD Supply Power Supply
D3 GND Supply Power Ground
D6 VDD Supply Power Supply
E2 GND Supply Power Ground
E3 VDD Supply Power Supply
E6 GND Supply Power Ground
E7 GND Supply Power Ground
F1 GND Supply Power Ground
F3 RST Input Reset
F6 GND Supply Power Ground
F8 GND Supply Power Ground
G2 GND Supply Power Ground
G3 CS Input SPI, Chip Select
G6 DIN Input SPI, Data Input
G7 GND Supply Power Supply
H1 VDD Supply Power Supply
H3 DOUT Output SPI, Data Output
H6 SCLK Input SPI, Serial Clock
H8 GND Supply Power Ground
Data Sheet ADIS16475
Rev. C | Page 9 of 37
Pin No. Mnemonic Type Description
J2 GND Supply Power Ground
J3 SYNC Input Sync (External Clock)
J4 VDD Supply Power Supply
J5 VDD Supply Power Supply
J6 DR Output Data Ready
J7 GND Supply Power Ground
K1 GND Supply Power Ground
K3 GND Supply Power Ground
K6 VDD Supply Power Supply
K8 GND Supply Power Ground
«nnv «m u
ADIS16475 Data Sheet
Rev. C | Page 10 of 37
TYPICAL PERFORMANCE CHARACTERISTICS
0.001 0.01 0.1 1 10 100 1000 10000 100000
INTEGRATION PERIOD (Seconds)
0.1
1
10
100
1000
ALLAN DEVI
A
TION (Degrees/hour)
X-AXIS
Y-AXIS
Z-AXIS
15436-008
Figure 8. Gyroscope Allan Deviation, TC = 25°C, ADIS16475-1
0.001 0.01 0.1 1 10 100 1000 10000 100000
INTEGRATION PERIOD (Seconds)
0.1
1
10
100
1000
ALLAN DEVI
A
TION (Degrees/hour)
X-AXIS
Y-AXIS
Z-AXIS
15436-009
Figure 9. Gyroscope Allan Deviation vs. TC = 25°C, ADIS16475-2
0.001 0.01 0.1 1 10 100 1000 10000 100000
INTEGRATION PERIOD (Seconds)
0.1
1
10
100
1000
ALLAN DEVIATION (Degrees/hour)
X-AXIS
Y-AXIS
Z-AXIS
15436-010
Figure 10. Gyroscope Allan Deviation, TC = 25°C, ADIS16475-3
0.001 0.01 0.1 1 10 100 1000 10000 100000
INTEGRATION PERIOD (Seconds)
ALLAN DEVI
A
TION (µg)
X-AXIS
Y-AXIS
Z-AXIS
15436-011
Figure 11. Accelerometer Allan Deviation, TC = 25°C
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE SENSITIVITY ERROR (%)
AMBIENT TEMPERATURE C)
15436-112
µ –
µ + 1σ
µ
Figure 12. ADIS16475-1 Gyroscope Sensitivity Error vs. Ambient Temperature
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE SENSITIVITY ERROR (%)
AMBIENT TEMPERATURE C)
µ
15436-113
µ
µ + 1σ
Figure 13. ADIS16475-2 Gyroscope Sensitivity Error vs. Ambient Temperature
Data Sheet ADIS16475
Rev. C | Page 11 of 37
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE SENSITIVITY ERROR (%)
AMBIENT TEMPERATURE (°C)
µ – 1σ
100
15436-114
µ + 1σ
µ
Figure 14. ADIS16475-3 Gyroscope Sensitivity Error vs. Ambient Temperature
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE BIAS ERROR /sec)
AMBIENT TEMPERATURE C)
15436-115
µ 1σ
µ + 1σ
µ
Figure 15. ADIS16475-1 Gyroscope Bias Error vs. Ambient Temperature
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE BIAS ERROR /sec)
AMBIENT TEMPERATURE (°C)
15436-116
µ – 1σ
µ + 1σ
µ
Figure 16. ADIS16475-2 Gyroscope Bias Error vs. Ambient Temperature
0.5
0.4
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
–60 –40 –20 0 20 40 60 80 100
GYROSCOPE BIAS ERROR /sec)
AMBIENT TEMPERATURE (°C)
15436-117
µ – 1σ
µ + 1σ
µ
Figure 17. ADIS16475-3 Gyroscope Bias Error vs. Ambient Temperature
ADIS16475 Data Sheet
Rev. C | Page 12 of 37
THEORY OF OPERATION
INTRODUCTION
When using the factory default configuration for all user
configurable control registers, the ADIS16475 initializes itself
and automatically starts a continuous process of sampling,
processing, and loading calibrated sensor data into its output
registers at a rate of 2000 SPS.
INERTIAL SENSOR SIGNAL CHAIN
Figure 18 provides the basic signal chain for the inertial sensors
in the ADIS16475. This signal chain produces an update rate
of 2000 SPS in the output data registers when it operates in
internal clock mode (default, see Register MSC_CTRL, Bits[4:2]
in Table 105).
OUTPUT
DATA
REGISTERS
AVERAGING
DECIMATING
FILTER
MEMS
SENSORS
15436-014
CALIBRATION
BARTLETT
WINDOW
FIR
FILTER
Figure 18. Signal Processing Diagram, Inertial Sensors
Gyroscope Data Sampling
The three gyroscopes produce angular rate measurements around
three orthogonal axes (x, y, and z). Figure 19 shows the data
sampling plan for each gyroscope when the ADIS16475 operates
in internal clock mode (default, see Register MSC_CTRL,
Bits[4:2] in Table 105). Each gyroscope has an analog-to-digital
converter (ADC) and sample clock (fSG) that drives data sampling
at a rate of 4100 Hz (±5%). The internal processor reads and
processes this data from each gyroscope at a rate of 2000 Hz (fSM).
MEMS
GYROSCOPE
f
SM
= 2000Hz
INTERNAL
DATA
REGISTER
f
SG
= 4100Hz
ADC
15436-015
TO
BARTLETT
WINDOW
FIR FILTER
Figure 19. Gyroscope Data Sampling
Accelerometer Data Sampling
The three accelerometers produce linear acceleration measurements
along the same orthogonal axes (x, y, and z) as the gyroscopes.
Figure 20 shows the data sampling plan for each accelerometer
when the ADIS16475 operates in internal clock mode (default,
see Register MSC_CTRL, Bits[4:2] in Table 105).
MEMS
ACCELEROMETER
2 ×
f
SM = 4000Hz
ADC 1
2
2
n = 1
a(n)
÷2
15436-016
TO
BARTLETT
WINDOW
FIR FILTER
Figure 20. Accelerometer Data Sampling
External Clock Options
The ADIS16475 provides three different modes of operation
that support the device using an external clock to control the
internal processing rate (fSM in Figure 19 and Figure 20) through
the SYNC pin. The MSC_CTRL register (see Table 105)
provides the configuration options for these external clock
modes in Bits[4:2].
Inertial Sensor Calibration
The inertial sensor calibration function for the gyroscopes and the
accelerometers has two components: factory calibration and user
calibration (see Figure 21).
TO
AVERAGING
DECIMATING
FILTER
FACTORY
CALIBRATION
USER
CALIBRATION
FROM
BARTLETT
WINDOW
FIR FILTER
15436-017
Figure 21. Inertial Sensor Calibration Processing
The factory calibration of the gyroscope applies the following
correction formulas to the data of each gyroscope:
ZC
YC
XC
333231
232221
131211
Z
Y
X
Z
Y
X
333231
232221
131211
ZC
YC
XC
a
a
a
lll
lll
lll
b
b
b
ω
ω
ω
mmm
mmm
mmm
ω
ω
ω
where:
ωXC, ωYC, and ωZC are the gyroscope outputs (post calibration).
m11, m12, m13, m21, m22, m23, m31, m32, and m33 provide scale and
alignment correction.
ωX, ωY, and ωZ are the gyroscope outputs (precalibration).
bX, bY, and bZ provide bias correction.
l11, l12, l13, l21, l22, l23, l31, l32, and l33 provide linear g correction
aXC, aYC, and aZC are the accelerometer outputs (post calibration).
All of the correction factors in this relationship come from
direct observation of the response of each gyroscope at multiple
temperatures over the calibration temperature range (−40°C ≤
TC ≤ +85°C). These correction factors are stored in the flash
memory bank, but they are not available for observation or
configuration. Register MSC_CTRL, Bit 7 (see Table 105)
provides the only user configuration option for the factory
calibration of the gyroscopes: an on/off control for the linear g
compensation. See Figure 44 for more details on the user
calibration options available for the gyroscopes.
Data Sheet ADIS16475
Rev. C | Page 13 of 37
The factory calibration of the accelerometer applies the following
correction formulas to the data of each accelerometer:
2
2
2
3231
2321
1312
333231
232221
131211
0
0
0
ZC
YC
XC
Z
Y
X
Z
Y
X
ZC
YC
XC
pp
pp
pp
b
b
b
a
a
a
mmm
mmm
mmm
a
a
a
where:
aXC, aYC, and aZC are the accelerometer outputs (post calibration).
m11, m12, m13, m21, m22, m23, m31, m32, and m33 provide scale and
alignment correction.
aX, aY, and aZ are the accelerometer outputs (precalibration).
bX, bY, and bZ provide bias correction.
p12, p13, p21, p23, p31, and p32 provide a point of percussion
alignment correction (see Figure 47).
ω2XC, ω2YC, and ω2ZC are the square of the gyroscope outputs
(post calibration).
All of the correction factors in this relationship come from
direct observation of the response of each accelerometer at
multiple temperatures over the calibration temperature range
(−40°C ≤ TC ≤ +85°C). These correction factors are stored
in the flash memory bank, but they are not available for
observation or configuration. MSC_CTRL, Bit 6 (see Table 105)
provides the only user configuration option for the factory
calibration of the accelerometers: an on/off control for the point of
percussion, alignment function. See Figure 45 for more details
on the user calibration options available for the accelerometers.
Bartlett Window FIR Filter
The Bartlett window finite impulse response (FIR) filter
(see Figure 22) contains two averaging filter stages in a cascade
configuration. The FILT_CTRL register (see Table 101) provides
the configuration controls for this filter.
FROM
MEMS
SENSOR
TO
FACTORY
CALIBRATION
1
N
N
n = 1
ω(n)
1
N
N
n = 1
ω(n)
15436-018
Figure 22. Bartlett Window FIR Filter Signal Path
Averaging/Decimating Filter
The second digital filter averages multiple samples together to
produce each register update. In this type of filter structure, the
number of samples in the average is equal to the reduction in
the update rate for the output data registers. The DEC_RATE
register (see Table 109) provides the configuration controls for
this filter.
FROM
USER
CALIBRATION ÷N
TO OUTPUT
REGISTERS
Σ
1
N
N
n = 1
ω(n)
15436-019
Figure 23. Averaging/Decimating Filter Diagram
REGISTER STRUCTURE
All communication between the ADIS16475 and an external
processor involves either reading the contents of an output
register or writing configuration/command information to a
control register. The output data registers include the latest
sensor data, error flags, and identification information. The
control registers include sample rate, filtering, calibration, and
diagnostic options. Each user accessible register has two bytes
(upper and lower), each of which has its own unique address.
See Table 8 for a detailed list of all user registers, along with
their addresses.
TRIAXIAL
GYROSCOPE
TEMPERATURE
SENSOR
TRIAXIAL
ACCELLEROMETER
OUTPUT
REGISTERS
CONTROL
REGISTERS
CONTROLLER
SENSOR
SIGNAL
PROCESSING
SPI
15436-020
Figure 24. Basic Operation of the ADIS16475
F53 A HHHHHIHHHHIH HHHHHHHHHHHHHHH 7: 4
ADIS16475 Data Sheet
Rev. C | Page 14 of 37
SERIAL PERIPHERAL INTERFACE (SPI)
The SPI provides access to the user registers (see Table 8). Figure 25
shows the most common connections between the ADIS16475 and
a SPI master device, which is often an embedded processor that
has a SPI-compatible interface. In this example, the SPI master
uses an interrupt service routine to collect data every time the
data ready (DR) signal pulses.
Additional information on the ADIS16475 SPI can be found in
the Serial Port Operation section of this data sheet.
CS
SYSTEM
PROCESSOR
SPI MASTER
VDD
I/O LINES ARE COMPATIBLE WITH
3.3V LOGIC LEVELS
SCLK
DIN
DR
DOUT
SS
SCLK
MOSI
IRQ
MISO
ADIS16475
+3.3V
15436-021
Figure 25. Electrical Connection Diagram
Table 6. Generic SPI Master Pin Names and Functions
Mnemonic Function
SS Slave select
SCLK Serial clock
MOSI Master output, slave input
MISO Master input, slave output
IRQ Interrupt request
Embedded processors typically use control registers to configure
their serial ports for communicating with SPI slave devices such
as the ADIS16475. Table 7 provides a list of settings that describe
the SPI protocol of the ADIS16475. The initialization routine
of the master processor typically establishes these settings using
firmware commands to write them into the control registers.
Table 7. Generic Master Processor SPI Settings
Processor Setting Description
Master ADIS16475 operates as slave
SCLK ≤ 2 MHz1 Maximum serial clock rate
SPI Mode 3 CPOL = 1 (polarity), CPHA = 1 (phase)
MSB First Mode Bit sequence, see Figure 30 for coding
16-Bit Mode Shift register and data length
1 A burst mode read requires this value to be ≤1 MHz (see Table 2 for more
information).
DATA READY (DR)
The factory default configuration provides users with a DR
signal on the DR pin (see Table 5), which pulses when the output
data registers are updating. Connect the DR pin to a pin on the
embedded processor, which triggers data collection, on the second
edge of this pulse. The MSC_CTRL register, Bit 0 (see Table 105),
controls the polarity of this signal. In Figure 26, Register
MSC_CTRL, Bit 0 = 1, which means that data collection must
start on the rising edges of the DR pulses.
DR
ACTIVE INACTIVE
15436-022
Figure 26. Data Ready When Register MSC_CTRL, Bit 0 = 1 (Default)
During the start-up and reset recovery processes, the DR signal
may exhibit some transient behavior before data production
begins. Figure 27 shows an example of the DR behavior during
startup, and Figure 28 and Figure 29 provide examples of the
DR behavior during recovery from reset commands.
VDD
DR
START-UP TIME
TIME THAT VDD > 3V
PULSING INDICATES
DATA PRODUCTION
15436-023
Figure 27. Data Ready Response During Startup
DR
RESET RECOVERY TIME
SOFTWARE RESET COMMAND
GLOB_CMD[7] = 1
DR PULSING
RESUMES
15436-024
Figure 28. Data Ready Response During Reset
(Register GLOB_CMD, Bit 7 = 1) Recovery
DR
RST
RESET RECOVERY TIME
RST PIN
RELEASED
DR PULSING
RESUMES
15436-025
Figure 29. Data Ready Response During Reset (RST = 0) Recovery
*1 r'fi mm a Wflfllflfllfllfllfllflflflflflllflflfllfllflflfllflfllflllflfllfllfllflflfllfllflfllfllfllflflfl 7D 7777777777777777777777 e+ 77777777777 77777777777 m
Data Sheet ADIS16475
Rev. C | Page 15 of 37
R/W R/W
A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0
D0D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15
CS
SCLK
DIN
DOUT
A6 A5
D13D14D15
NOTES
1. DOUT BITS ARE PRODUCED ONLY WHEN THE PREVIOUS 16-BIT DIN SEQUENCE STARTS WITH R/W = 0.
2. WHEN CS IS HIGH, DOUT IS IN A THREE-STATE, HIGH IMPEDANCE MODE, WHICH ALLOWS MULTIFUNCTIONAL USE OF THE LINE
FOR OTHER DEVICES.
15436-026
Figure 30. SPI Communication Bit Sequence
CS 12311
SCLK
DIN
DOUT
0x6800
DIAG_STAT XGYRO_OUT CHECKSUM
15436-027
Figure 31. Burst Read Sequence
CS
SCLK
DIN
DOUT
DIN = 0x7200 = 0111 0010 0000 0000
DOUT = 0100 0000 0101 1011 = 0x405B = 16475 (PROD_ID)
15436-028
HIGH-ZHIGH-Z
Figure 32. SPI Signal Pattern Showing a Read of the PROD_ID Register
READING SENSOR DATA
Reading a single register requires two 16-bit cycles on the SPI:
one to request the contents of a register and another to receive
those contents. The 16-bit command code (see Figure 30) for a
read request on the SPI has three parts: the read bit (R/W = 0),
either address of the register, [A6:A0], and eight dont care bits,
[DC7:DC0]. Figure 33 shows an example that includes two register
reads in succession. This example starts with DIN = 0x0C00 to
request the contents of the Z_GYRO_LOW register, and follows
with 0x0E00 to request the contents of the Z_GYRO_OUT register.
The sequence in Figure 33 also shows full duplex mode of
operation, which means that the ADIS16475 can receive requests
on DIN while also transmitting data out on DOUT within the
same 16-bit SPI cycle.
DIN
DOUT
0x0C00 0x0E00 NEXT
ADDRESS
Z_GYRO_LOW Z_GYRO_OUT
15436-029
Figure 33. SPI Read Example
Figure 32 provides an example of the four SPI signals when reading
the PROD_ID register (see Table 121) in a repeating pattern.
This pattern can be helpful when troubleshooting the SPI
interface setup and communications because the signals are
the same for each 16-bit sequence, except during the first cycle.
Burst Read Function
The burst read function provides a way to read a batch of
output data registers, using a continuous stream of bits, at a rate
of up to 1 MHz (SCLK). This method does not require a stall
time between each 16-bit segment (see Figure 3). As shown in
Figure 31, start this mode by setting DIN = 0x6800, and then
read each of the registers in the sequence out of DOUT while
keeping CS low for the entire 176-bit sequence.
The sequence of registers (and checksum value) in the burst read
response depends on which sample clock mode that the ADIS16475
is operating in (Register MSC_CTRL, Bits[4:2], see Table 105).
In all clock modes, except when operating in scaled sync mode
(Register MSC_CTRL, Bits[4:2] = 010), the burst read response
includes the following registers and value: DIAG_STAT,
X_GYRO_OUT, Y_GYRO_OUT, Z_GYRO_OUT, X_ACCL_
OUT, Y_ACCL_OUT, Z_ACCL_OUT, TEMP_OUT, DATA_
CNTR, and the checksum value. In these cases, use the following
formula to verify the checksum value, treating each byte in the
formula as an independent, unsigned, 8-bit number:
Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +
X_GYRO_OUT, Bits[15:8] + X_GYRO_OUT, Bits[7:0] +
Y_GYRO_OUT, Bits[15:8] + Y_GYRO_OUT, Bits[7:0] +
Z_GYRO_OUT, Bits[15:8] + Z_GYRO_OUT, Bits[7:0] +
X_ACCL_OUT, Bits[15:8] + X_ACCL_OUT, Bits[7:0] +
Y_ACCL_OUT, Bits[15:8] + Y_ACCL_OUT, Bits[7:0] +
Z_ACCL_OUT, Bits[15:8] + Z_ACCL_OUT, Bits[7:0] +
TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] +
DATA_CNTR, Bits[15:8] + DATA_CNTR, Bits[7:0]
ADIS16475 Data Sheet
Rev. C | Page 16 of 37
When operating in scaled sync mode (Register MSC_CTRL,
Bits[4:2] = 010), the burst read response includes the following
registers and value: DIAG_STAT, X_GYRO_OUT, Y_GYRO_OUT,
Z_GYRO_OUT, X_ACCL_OUT, Y_ACCL_OUT, Z_ACCL_OUT,
TEMP_OUT, TIME_STAMP, and the checksum value. In this
case, use the following formula to verify the checksum value,
treating each byte in the formula as an independent, unsigned,
8-bit number.
Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +
X_GYRO_OUT, Bits[15:8] + X_GYRO_OUT, Bits[7:0] +
Y_GYRO_OUT, Bits[15:8] + Y_GYRO_OUT, Bits[7:0] +
Z_GYRO_OUT, Bits[15:8] + Z_GYRO_OUT, Bits[7:0] +
X_ACCL_OUT, Bits[15:8] + X_ACCL_OUT, Bits[7:0] +
Y_ACCL_OUT, Bits[15:8] + Y_ACCL_OUT, Bits[7:0] +
Z_ACCL_OUT, Bits[15:8] + Z_ACCL_OUT, Bits[7:0] +
TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] +
TIME_STAMP, Bits[15:8] + TIME_STAMP, Bits[7:0]
DEVICE CONFIGURATION
Each configuration register contains 16 bits (two bytes). Bits[7:0]
contain the low byte, and Bits[15:8] contain the high byte of
each register. Each byte has its own unique address in the user
register map (see Table 8). Updating the contents of a register
requires writing to both of its bytes in the following sequence:
low byte first, high byte second. There are three parts to coding
a SPI command (see Figure 30) that write a new byte of data to
a register: the write bit (R/W = 1), the address of the byte, [A6:A0],
and the new data for that location, [DC7:DC0]. Figure 34 shows
a coding example for writing 0x0004 to the FILT_CTRL register
(see Table 101). In Figure 34, the 0xDC04 command writes 0x04 to
Address 0x5C (lower byte) and the 0xDD00 command writes
0x00 to Address 0x5D (upper byte).
CS
S
CL
K
DIN 0xDC04 0xDD00
15436-030
Figure 34. SPI Sequence for Writing 0x0004 to FILT_CTRL
Memory Structure
Figure 35 provides a functional diagram for the memory
structure of the ADIS16475. The flash memory bank contains
the operational code, unit specific calibration coefficients, and
user configuration settings. During initialization (power
application or reset recover), this information loads from the
flash memory into the static random access memory (SRAM),
which supports all normal operation, including register access
through the SPI port. Writing to a configuration register using
the SPI updates the SRAM location of the register, but does not
automatically update its settings in the flash memory bank. The
manual flash memory update command (Register GLOB_CMD,
Bit 3, see Table 113) provides a convenient method for saving all
of these settings to the flash memory bank at one time. A yes in
the flash backup column of Table 8 identifies the registers that
have storage support in the flash memory bank.
NONVOLATILE
FLASH MEMORY
(NO SPI ACCESS)
MANUAL
FLASH
BACKUP
START-UP
RESET
VOLATILE
SRAM
SPI ACCESS
15436-031
Figure 35. SRAM and Flash Memory Diagram
Data Sheet ADIS16475
Rev. C | Page 17 of 37
USER REGISTER MEMORY MAP
Table 8. User Register Memory Map (N/A Means Not Applicable)
Name R/W Flash Backup Address Default Register Description
Reserved N/A N/A 0x00, 0x01 N/A Reserved
DIAG_STAT R No 0x02, 0x03 0x0000 Output, system error flags
X_GYRO_LOW R No 0x04, 0x05 N/A Output, x-axis gyroscope, low word
X_GYRO_OUT R No 0x06, 0x07 N/A Output, x-axis gyroscope, high word
Y_GYRO_LOW R No 0x08, 0x09 N/A Output, y-axis gyroscope, low word
Y_GYRO_OUT R No 0x0A, 0x0B N/A Output, y-axis gyroscope, high word
Z_GYRO_LOW R No 0x0C, 0x0D N/A Output, z-axis gyroscope, low word
Z_GYRO_OUT R No 0x0E, 0x0F N/A Output, z-axis gyroscope, high word
X_ACCL_LOW R No 0x10, 0x11 N/A Output, x-axis accelerometer, low word
X_ACCL_OUT R No 0x12, 0x13 N/A Output, x-axis accelerometer, high word
Y_ACCL_LOW R No 0x14, 0x15 N/A Output, y-axis accelerometer, low word
Y_ACCL_OUT R No 0x16, 0x17 N/A Output, y-axis accelerometer, high word
Z_ACCL_LOW R No 0x18, 0x19 N/A Output, z-axis accelerometer, low word
Z_ACCL_OUT R No 0x1A, 0x1B N/A Output, z-axis accelerometer, high word
TEMP_OUT R No 0x1C, 0x1D N/A Output, temperature
TIME_STAMP R No 0x1E, 0x1F N/A Output, time stamp
Reserved N/A N/A 0x20, 0x21 N/A Reserved
DATA_CNTR R No 0x22, 0x23 N/A New data counter
X_DELTANG_LOW R No 0x24, 0x25 N/A Output, x-axis delta angle, low word
X_DELTANG_OUT R No 0x26, 0x27 N/A Output, x-axis delta angle, high word
Y_DELTANG_LOW R No 0x28, 0x29 N/A Output, y-axis delta angle, low word
Y_DELTANG_OUT R No 0x2A, 0x2B N/A Output, y-axis delta angle, high word
Z_DELTANG_LOW R No 0x2C, 0x2D N/A Output, z-axis delta angle, low word
Z_DELTANG_OUT R No 0x2E, 0x2F N/A Output, z-axis delta angle, high word
X_DELTVEL_LOW R No 0x30, 0x31 N/A Output, x-axis delta velocity, low word
X_DELTVEL_OUT R No 0x32, 0x33 N/A Output, x-axis delta velocity, high word
Y_DELTVEL_LOW R No 0x34, 0x35 N/A Output, y-axis delta velocity, low word
Y_DELTVEL_OUT R No 0x36, 0x37 N/A Output, y-axis delta velocity, high word
Z_DELTVEL_LOW R No 0x38, 0x39 N/A Output, z-axis delta velocity, low word
Z_DELTVEL_OUT R No 0x3A, 0x3B N/A Output, z-axis delta velocity, high word
Reserved N/A N/A 0x3C to 0x3F N/A Reserved
XG_BIAS_LOW R/W Yes 0x40, 0x41 0x0000 Calibration, offset, gyroscope, x-axis, low word
XG_BIAS_HIGH R/W Yes 0x42, 0x43 0x0000 Calibration, offset, gyroscope, x-axis, high word
YG_BIAS_LOW R/W Yes 0x44, 0x45 0x0000 Calibration, offset, gyroscope, y-axis, low word
YG_BIAS_HIGH R/W Yes 0x46, 0x47 0x0000 Calibration, offset, gyroscope, y-axis, high word
ZG_BIAS_LOW R/W Yes 0x48, 0x49 0x0000 Calibration, offset, gyroscope, z-axis, low word
ZG_BIAS_HIGH R/W Yes 0x4A, 0x4B 0x0000 Calibration, offset, gyroscope, z-axis, high word
XA_BIAS_LOW R/W Yes 0x4C, 0x4D 0x0000 Calibration, offset, accelerometer, x-axis, low word
XA_BIAS_HIGH R/W Yes 0x4E, 0x4F 0x0000 Calibration, offset, accelerometer, x-axis, high word
YA_BIAS_LOW R/W Yes 0x50, 0x51 0x0000 Calibration, offset, accelerometer, y-axis, low word
YA_BIAS_HIGH R/W Yes 0x52, 0x53 0x0000 Calibration, offset, accelerometer, y-axis, high word
ZA_BIAS_LOW R/W Yes 0x54, 0x55 0x0000 Calibration, offset, accelerometer, z-axis, low word
ZA_BIAS_HIGH R/W Yes 0x56, 0x57 0x0000 Calibration, offset, accelerometer, z-axis, high word
Reserved N/A N/A 0x58 to 0x5B N/A Reserved
FILT_CTRL R/W Yes 0x5C, 0x5D 0x0000 Control, Bartlett window FIR filter
RANG_MDL R No 0x5E, 0x5F N/A1 Measurement range (model specific) identifier
MSC_CTRL R/W Yes 0x60, 0x61 0x00C1 Control, input/output and other miscellaneous options
UP_SCALE R/W Yes 0x62, 0x63 0x07D0
Control, scale factor for input clock, pulse per second (PPS)
mode
DEC_RATE R/W Yes 0x64, 0x65 0x0000 Control, decimation filter (output data rate)
ADIS16475 Data Sheet
Rev. C | Page 18 of 37
Name R/W Flash Backup Address Default Register Description
NULL_CNFG R/W Yes 0x66, 0x67 0x070A Control, bias estimation period
GLOB_CMD W No 0x68, 0x69 N/A Control, global commands
Reserved N/A N/A 0x6A to 0x6B N/A Reserved
FIRM_REV R No 0x6C, 0x6D N/A Identification, firmware revision
FIRM_DM R No 0x6E, 0x6F N/A Identification, date code, day and month
FIRM_Y R No 0x70, 0x71 N/A Identification, date code, year
PROD_ID R No 0x72, 0x73 0x405B Identification, device number
SERIAL_NUM R No 0x74, 0x75 N/A Identification, serial number
USER_SCR_1 R/W Yes 0x76, 0x77 N/A User Scratch Register 1
USER_SCR_2 R/W Yes 0x78, 0x79 N/A User Scratch Register 2
USER_SCR_3 R/W Yes 0x7A, 0x7B N/A User Scratch Register 3
FLSHCNT_LOW R No 0x7C, 0x7D N/A Output, flash memory write cycle counter, lower word
FLSHCNT_HIGH R No 0x7E, 0x7E N/A Output, flash memory write cycle counter, upper word
1 See Table 102 for the default value in this register, which is model specific.
Data Sheet ADIS16475
Rev. C | Page 19 of 37
USER REGISTER DEFINTIONS
Status/Error Flag Indicators (DIAG_STAT)
Table 9. DIAG_STAT Register Definition
Addresses Default Access Flash Backup
0x02, 0x03 0x0000 R No
Table 10. DIAG_STAT Bit Assignments
Bits Description
[15:8] Reserved.
7 Clock error. A 1 indicates that the internal data sampling
clock (fSM, see Figure 19 and Figure 20) does not
synchronize with the external clock, which only applies
when using scaled sync mode (Register MSC_CTRL,
Bits[4:2] = 010, see Table 105). When this error occurs,
adjust the frequency of the clock signal on the SYNC pin
to operate within the appropriate range.
6 Memory failure. A 1 indicates a failure in the flash memory
test (Register GLOB_CMD, Bit 4, see Table 113), which
involves a comparison between a cyclic redundancy
check (CRC) calculation of the present flash memory and
a CRC calculation from the same memory locations at
the time of initial programming (during the production
process). If this error occurs, repeat the same test. If this
error persists, replace the ADIS16475 device.
5 Sensor failure. A 1 indicates failure of at least one sensor,
at the conclusion of the self test (Register GLOB_CMD,
Bit 2, see Table 113). If this error occurs, repeat the same
test. If this error persists, replace the ADIS16475. Motion
during the execution of this test can cause a false failure.
4 Standby mode. A 1 indicates that the voltage across
VDD and GND is <2.8 V, which causes data processing to
stop. When VDD ≥ 2.8 V for 250 ms, the ADIS16475
reinitializes itself and starts producing data again.
3 SPI communication error. A 1 indicates that the total
number of SCLK cycles is not equal to an integer
multiple of 16. When this error occurs, repeat the
previous communication sequence. Persistence in this
error may indicate a weakness in the SPI service that the
ADIS16475 is receiving from the system it is supporting.
2 Flash memory update failure. A 1 indicates that the most
recent flash memory update (Register GLOB_CMD, Bit 3, see
Table 113) failed. If this error occurs, ensure that VDD ≥ 3 V
and repeat the update attempt. If this error persists,
replace the ADIS16475.
1 Data path overrun. A 1 indicates that one of the data
paths experienced an overrun condition. If this error
occurs, initiate a reset using the RST pin (see Table 5,
Pin F3) or Register GLOB_CMD, Bit 7 (see Table 113). See
the Serial Port Operation section for more details on
conditions that may cause this bit to be set to 1.
0 Reserved.
The DIAG_STAT register (see Table 9 and Table 10) provides
error flags for monitoring the integrity and operation of the
ADIS16475. Reading this register causes all of its bits to return
to 0. The error flags in DIAG_STAT are sticky, meaning that,
when they raise to a 1, they remain there until a read request
clears them. If an error condition persists, the flag (bit)
automatically returns to an alarm value of 1.
GYROSCOPE DATA
The gyroscopes in the ADIS16475 measure the angular rate of
rotation around three orthogonal axes (x, y, and z). Figure 36
shows the orientation of each gyroscope axis, along with the
direction of rotation that produces a positive response in each
of their measurements.
ω
Z
ω
Y
Y
ω
X
Z
X
PIN A8 PIN K1
15436-032
Figure 36. Gyroscope Axis and Polarity Assignments
Each gyroscope has two output data registers. Figure 37 shows
how these two registers combine to support a 32-bit, twos
complement data format for the x-axis gyroscope measurements.
This format also applies to the y- and z-axes.
Additional information on the precision and resolution of the
accelerometers can be found in the Digital Resolution of
Gyroscopes and Accelerometers section of this data sheet.
X-AXIS GYROSCOPE DATA
X_GYRO_OUT X_GYRO_LOW
15436-033
BIT0 BIT15BIT 15 BIT 0
Figure 37. Gyroscope Output Data Structure
Gyroscope Measurement Range/Scale Factor
Table 11 provides the measurement range (±ωMAX) and scale
factor (KG) for the gyroscope in each ADIS16475 model.
Table 11. Gyroscope Measurement Range and Scale Factors
Model
Range, ±ωMAX
(°/sec)
Scale Factor, KG
(LSB/°/sec)
ADIS16475-1 ±125 160
ADIS16475-2 ±500 40
ADIS16475-3 ±2000 10
Gyroscope Data Formatting
Table 12 and Table 13 offer various numerical examples that
demonstrate the format of the rotation rate data in both 16-bit
and 32-bit formats.
Table 12. 16-Bit Gyroscope Data Format Examples
Rotation Rate Decimal Hex Binary
MAX +20,000 0x4E20 0100 1110 0010 0000
+2/KG +2 0x0002 0000 0000 0000 0010
+1/KG +1 0x0001 0000 0000 0000 0001
0°/sec 0 0x0000 0000 0000 0000 0000
−1/KG −1 0xFFFF 1111 1111 1111 1111
−2/KG −2 0xFFFE 1111 1111 1111 1110
−ωMAX −20,000 0xB1E0 1011 0001 1110 0000
ADIS16475 Data Sheet
Rev. C | Page 20 of 37
Table 13. 32-Bit Gyroscope Data Format Examples
Rotation Rate (°/sec) Decimal Hex
MAX +1,310,720,000 0x4E200000
+2/(KG × 216) +2 0x00000002
+1/(KG × 216) +1 0x00000001
0 0 0x0000000
−1/(KG × 216) −1 0xFFFFFFFF
−2/(KG × 216) −2 0xFFFFFFFE
−ωMAX −1,310,720,000 0xB1E00000
X-Axis Gyroscope (X_GYRO_LOW and X_GYRO_OUT)
Table 14. X_GYRO_LOW Register Definition
Addresses Default Access Flash Backup
0x04, 0x05 Not applicable R No
Table 15. X_GYRO_LOW Bit Definitions
Bits Description
[15:0] X-axis gyroscope data; additional resolution bits
Table 16. X_GYRO_OUT Register Definition
Addresses Default Access Flash Backup
0x06, 0x07 Not applicable R No
Table 17. X_GYRO_OUT Bit Definitions
Bits Description
[15:0] X-axis gyroscope data; high word; twos complement,
0°/sec = 0x0000, 1 LSB = 1/KG (See Table 11 for KG)
The X_GYRO_LOW (see Table 14 and Table 15) and X_GYRO_
OUT (see Table 16 and Table 17) registers contain the gyroscope
data for the x-axis.
Y-Axis Gyroscope (Y_GYRO_LOW and Y_GYRO_OUT)
Table 18. Y_GYRO_LOW Register Definition
Addresses Default Access Flash Backup
0x08, 0x09 Not applicable R No
Table 19. Y_GYRO_LOW Bit Definitions
Bits Description
[15:0] Y-axis gyroscope data; additional resolution bits
Table 20. Y_GYRO_OUT Register Definition
Addresses Default Access Flash Backup
0x0A, 0x0B Not applicable R No
Table 21. Y_GYRO_OUT Bit Definitions
Bits Description
[15:0] Y-axis gyroscope data; high word; twos complement,
0°/sec = 0x0000, 1 LSB = 1/KG (see Table 11 for KG)
The Y_GYRO_LOW (see Table 18 and Table 19) and Y_GYRO_
OUT (see Table 20 and Table 21) registers contain the gyroscope
data for the y-axis.
Z-Axis Gyroscope (Z_GYRO_LOW and Z_GYRO_OUT)
Table 22. Z_GYRO_LOW Register Definition
Addresses Default Access Flash Backup
0x0C, 0x0D Not applicable R No
Table 23. Z_GYRO_LOW Bit Definitions
Bits Description
[15:0] Z-axis gyroscope data; additional resolution bits
Table 24. Z_GYRO_OUT Register Definition
Addresses Default Access Flash Backup
0x0E, 0x0F Not applicable R No
Table 25. Z_GYRO_OUT Bit Definitions
Bits Description
[15:0] Z-axis gyroscope data; high word; twos complement,
0°/sec = 0x0000, 1 LSB = 1/KG (see Table 11 for KG)
The Z_GYRO_LOW (see Table 22 and Table 23) and Z_GYRO_
OUT (see Table 24 and Table 25) registers contain the gyroscope
data for the z-axis.
Acceleration Data
The accelerometers in the ADIS16475 measure both dynamic
and static (response to gravity) acceleration along the same three
orthogonal axes that define the axes of rotation for the gyroscopes
(x, y, and z). Figure 38 shows the orientation of each accelerometer
axis, along with the direction of acceleration that produces a
positive response in each of their measurements.
a
z
a
x
a
y
Z
X
Y
PIN A8 PIN K1
15436-034
Figure 38. Accelerometer Axis and Polarity Assignments
Each accelerometer has two output data registers. Figure 39
shows how these two registers combine to support a 32-bit,
twos complement data format for the x-axis accelerometer
measurements. This format also applies to the y- and z-axes.
Additional information on the precision and resolution of the
accelerometers can be found in the Digital Resolution of
Gyroscopes and Accelerometers section of this data sheet.
X-AXIS ACCELEROMETER DATA
X_ACCL_OUT X_ACCL_LOW
15436-035
BIT0 BIT15BIT 15 BIT 0
Figure 39. Accelerometer Output Data Structure
Data Sheet ADIS16475
Rev. C | Page 21 of 37
Accelerometer Data Formatting
Table 26 and Table 27 offer various numerical examples that
demonstrate the format of the linear acceleration data in both
16-bit and 32-bit formats.
Table 26. 16-Bit Accelerometer Data Format Examples
Acceleration Decimal Hex Binary
+8 g +32,000 0x7D00 0111 1101 0000 0000
+0.5 mg +2 0x0002 0000 0000 0000 0010
+0.25 mg +1 0x0001 0000 0000 0000 0001
0 mg 0 0x0000 0000 0000 0000 0000
−0.25 mg −1 0xFFFF 1111 1111 1111 1111
−0.5 mg −2 0xFFFE 1111 1111 1111 1110
−8 g −32,000 0x8300 1000 0011 0000 0000
Table 27. 32-Bit Accelerometer Data Format Examples
Acceleration Decimal Hex
+8 g +2,097,152,000 0x7D000000
+0.25/215 mg +2 0x00000002
+0.25/216 mg +1 0x00000001
0 0 0x00000000
−0.25/216 mg −1 0xFFFFFFFF
−0.25/215 mg −2 0xFFFFFFFE
−8 g −2,097,152,000 0x83000000
X-Axis Accelerometer (X_ACCL_LOW and X_ACCL_OUT)
Table 28. X_ACCL_LOW Register Definition
Addresses Default Access Flash Backup
0x10, 0x11 Not applicable R No
Table 29. X_ACCL_LOW Bit Definitions
Bits Description
[15:0] X-axis accelerometer data; additional resolution bits
Table 30. X_ACCL_OUT Register Definition
Addresses Default Access Flash Backup
0x12, 0x13 Not applicable R No
Table 31. X_ACCL_OUT Bit Definitions
Bits Description
[15:0] X-axis accelerometer data, high word; twos
complement, ±8 g range; 0 g = 0x0000, 1 LSB = 0.25 mg
The X_ACCL_LOW (see Table 28 and Table 29) and X_ACCL_
OUT (see Table 30 and Table 31) registers contain the
accelerometer data for the x-axis.
Y-Axis Accelerometer (Y_ACCL_LOW and Y_ACCL_OUT)
Table 32. Y_ACCL_LOW Register Definition
Addresses Default Access Flash Backup
0x14, 0x15 Not applicable R No
Table 33. Y_ACCL_LOW Bit Definitions
Bits Description
[15:0] Y-axis accelerometer data; additional resolution bits
Table 34. Y_ACCL_OUT Register Definition
Addresses Default Access Flash Backup
0x16, 0x17 Not applicable R No
Table 35. Y_ACCL_OUT Bit Definitions
Bits Description
[15:0] Y-axis accelerometer data, high word; twos
complement, ±8 g range; 0 g = 0x0000, 1 LSB = 0.25 mg
The Y_ACCL_LOW (see Table 32 and Table 33) and Y_ACCL_
OUT (see Table 34 and Table 35) registers contain the
accelerometer data for the y-axis.
Z-Axis Accelerometer (Z_ACCL_LOW and Z_ACCL_OUT)
Table 36. Z_ACCL_LOW Register Definition
Addresses Default Access Flash Backup
0x18, 0x19 Not applicable R No
Table 37. Z_ACCL_LOW Bit Definitions
Bits Description
[15:0] Z-axis accelerometer data; additional resolution bits
Table 38. Z_ACCL_OUT Register Definition
Addresses Default Access Flash Backup
0x1A, 0x1B Not applicable R No
Table 39. Z_ACCL_OUT Bit Definitions
Bits Description
[15:0] Z-axis accelerometer data, high word; twos
complement, ±8 g range; 0 g = 0x0000, 1 LSB = 0.25 mg
The Z_ACCL_LOW (see Table 36 and Table 37) and Z_ACCL_
OUT (see Table 38 and Table 39) registers contain the
accelerometer data for the z-axis.
ADIS16475 Data Sheet
Rev. C | Page 22 of 37
Internal Temperature (TEMP_OUT)
Table 40. TEMP_OUT Register Definition
Addresses Default Access Flash Backup
0x1C, 0x1D Not applicable R No
Table 41. TEMP_OUT Bit Definitions
Bits Description
[15:0] Temperature data; twos complement, 1 LSB = 0.1°C, 0°C =
0x0000
The TEMP_OUT register (see Table 40 and Table 41) provides a
coarse measurement of the temperature inside of the ADIS16475.
This data is most useful for monitoring relative changes in the
thermal environment.
Table 42. TEMP_OUT Data Format Examples
Temperature (°C) Decimal Hex Binary
+105 +1050 0x041A 0000 0100 0001 1010
+25 +250 0x00FA 0000 0000 1111 1010
+0.2 +2 0x0002 0000 0000 0000 0010
+0.1 +1 0x0001 0000 0000 0000 0001
+0 0 0x0000 0000 0000 0000 0000
+0.1 −1 0xFFFF 1111 1111 1111 1111
+0.2 −2 0xFFFE 1111 1111 1111 1110
−40 −400 0xFE70 1111 1110 0111 0000
Time Stamp (TIME_STAMP)
Table 43. TIME_STAMP Register Definition
Addresses Default Access Flash Backup
0x1E, 0x1F Not applicable R No
Table 44. TIME_STAMP Bit Definitions
Bits Description
[15:0] Time from the last pulse on the SYNC pin; offset binary
format, 1 LSB = 49.02 µs
The TIME_STAMP register (see Table 43 and Table 44) works
in conjunction with scaled sync mode (Register MSC_CTRL,
Bits[4:2] = 010, see Table 105). The 16-bit number in TIME_
STAMP contains the time associated with the last sample in
each data update relative to the most recent edge of the clock
signal in the SYNC pin. For example, when the value in the
UP_SCALE register (see Table 107) represents a scale factor of
20, DEC_RATE = 0, and the external SYNC rate = 100 Hz, the
following time stamp sequence results: 0 LSB, 10 LSB, 21 LSB,
31 LSB, 41 LSB, 51 LSB, 61 LSB, 72 LSB, …, 194 LSB for the 20th
sample, which translates to 0 μs, 490 μs, …, 9510 μs, the time
from the first SYNC edge.
Data Update Counter (DATA_CNTR)
Table 45. DATA_CNTR Register Definition
Addresses Default Access Flash Backup
0x22, 0x23 Not applicable R No
Table 46. DATA_CNTR Bit Definitions
Bits Description
[15:0] Data update counter, offset binary format
When the ADIS16475 goes through its power-on sequence or
when it recovers from a reset command, DATA_CNTR (see
Table 45 and Table 46) starts with a value of 0x0000 and
increments every time new data loads into the output registers.
When the DATA_CNTR value reaches 0xFFFF, the next data
update causes it to wrap back around to 0x0000, where it continues
to increment every time new data loads into the output registers.
DELTA ANGLES
In addition to the angular rate of rotation (gyroscope)
measurements around each axis (x, y, and z), the ADIS16475 also
provides delta angle measurements that represent a calculation of
angular displacement between each sample update.
Δθ
Z
Δθ
Y
Y
Δθ
X
Z
X
PIN A8 PIN K1
15436-036
Figure 40. Delta Angle Axis and Polarity Assignments
The delta angle outputs represent an integration of the gyroscope
measurements and use the following formula for all three axes
(x-axis displayed):
1
0
1,,
,2
1D
d
dDnxdDnx
S
Dnx f
where:
D is the decimation rate (DEC_RATE + 1, see Table 109).
fS is the sample rate.
d is the incremental variable in the summation formula.
ωX is the x-axis rate of rotation (gyroscope).
n is the sample time, prior to the decimation filter.
When using the internal sample clock, fS is equal to a nominal
rate of 2000 SPS. For better precision in this measurement,
measure the internal sample rate (fS) using the data ready signal
on the DR pin (DEC_RATE = 0x0000, see Table 108), divide
each delta angle result (from the delta angle output registers) by
the data ready frequency, and multiply it by 2000. Each axis of
the delta angle measurements has two output data registers.
Figure 41 shows how these two registers combine to support a
32-bit, twos complement data format for the x-axis delta angle
measurements. This format also applies to the y- and z-axes.
Data Sheet ADIS16475
Rev. C | Page 23 of 37
X-AXIS DELTA ANGLE DATA
X_DELTANG_OUT X_DELTANG_LOW
15436-037
BIT0 BIT15BIT 15 BIT 0
Figure 41. Delta Angle Output Data Structure
Delta Angle Measurement Range
Table 47 shows the measurement range and scale factor for each
ADIS16475 model.
Table 47. Delta Angle Measurement Range and Scale Factor
Model Measurement Range, ±ΔΘMAX (°)
ADIS16475-1BMLZ ±360
ADIS16475-2BMLZ ±720
ADIS16475-3BMLZ ±2160
X-Axis Delta Angle (X_DELTANG_LOW and
X_DELTANG_OUT)
Table 48. X_DELTANG_LOW Register Definitions
Addresses Default Access Flash Backup
0x24, 0x25 Not applicable R No
Table 49. X_DELTANG_LOW Bit Definitions
Bits Description
[15:0] X-axis delta angle data; low word
Table 50. X_DELTANG_OUT Register Definitions
Addresses Default Access Flash Backup
0x26, 0x27 Not applicable R No
Table 51. X_DELTANG_OUT Bit Definitions
Bits Description
[15:0] X-axis delta angle data; twos complement, 0° = 0x0000,
1 LSB = ∆θMAX/215 (see Table 47 for ∆θMAX)
The X_DELTANG_LOW (see Table 48 and Table 49) and
X_DELTANG_OUT (see Table 50 and Table 51) registers
contain the delta angle data for the x-axis.
Y-Axis Delta Angle (Y_DELTANG_LOW and
Y_DELTANG_OUT)
Table 52. Y_DELTANG_LOW Register Definitions
Addresses Default Access Flash Backup
0x28, 0x29 Not applicable R No
Table 53. Y_DELTANG_LOW Bit Definitions
Bits Description
[15:0] Y-axis delta angle data; low word
Table 54. Y_DELTANG_OUT Register Definitions
Addresses Default Access Flash Backup
0x2A, 0x2B Not applicable R No
Table 55. Y_DELTANG_OUT Bit Definitions
Bits Description
[15:0] Y-axis delta angle data; twos complement, 0° = 0x0000,
1 LSB = ∆θMAX/215 (see Table 47 for ∆θMAX)
The Y_DELTANG_LOW (see Table 52 and Table 53) and
Y_DELTANG_OUT (see Table 54 and Table 55) registers
contain the delta angle data for the y-axis.
Z-Axis Delta Angle (Z_DELTANG_LOW and
Z_DELTANG_OUT)
Table 56. Z_DELTANG_LOW Register Definitions
Addresses Default Access Flash Backup
0x2C, 0x2D Not applicable R No
Table 57. Z_DELTANG_LOW Bit Definitions
Bits Description
[15:0] Z-axis delta angle data; low word
Table 58. Z_DELTANG_OUT Register Definitions
Addresses Default Access Flash Backup
0x2E, 0x2F Not applicable R No
Table 59. Z_DELTANG_OUT Bit Definitions
Bits Description
[15:0] Z-axis delta angle data; twos complement, 0° = 0x0000,
1 LSB = ∆θMAX/215 (see Table 47 for ∆θMAX)
The Z_DELTANG_LOW (see Table 56 and Table 57) and
Z_DELTANG_OUT (see Table 58 and Table 59) registers
contain the delta angle data for the z-axis.
Delta Angle Resolution
Table 60 and Table 61 show various numerical examples that
demonstrate the format of the delta angle data in both 16-bit
and 32-bit formats.
Table 60. 16-Bit Delta Angle Data Format Examples
Delta Angle (°) Decimal Hex Binary
∆θMAX × (215−1)/215 +32,767 0x7FFF 0111 1111 1110 1111
+∆θMAX/214 +2 0x0002 0000 0000 0000 0010
+∆θMAX/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−∆θMAX/215 −1 0xFFFF 1111 1111 1111 1111
−∆θMAX/214 −2 0xFFFE 1111 1111 1111 1110
−∆θMAX −32,768 0x8000 1000 0000 0000 0000
Table 61. 32-Bit Delta Angle Data Format Examples
Delta Angle (°) Decimal Hex
+∆θMAX × (231 − 1)/231 +2,147,483,647 0x7FFFFFFF
+∆θMAX/230 +2 0x00000002
+∆θMAX/231 +1 0x00000001
0 0 0x00000000
−∆θMAX/231 −1 0xFFFFFFFF
−∆θMAX/230 −2 0xFFFFFFFE
−∆θMAX −2,147,483,648 0x80000000
DELTA VELOCITY
In addition to the linear acceleration measurements along each
axis (x, y, and z), the ADIS16475 also provides delta velocity
measurements that represent a calculation of linear velocity
change between each sample update.
ADIS16475 Data Sheet
Rev. C | Page 24 of 37
Z
X
Y
PIN A8 PIN K1
ΔV
Z
ΔV
X
ΔV
Y
15436-038
Figure 42. Delta Velocity Axis and Polarity Assignments
The delta velocity outputs represent an integration of the
acceleration measurements and use the following formula for all
three axes (x-axis displayed):

1
0
1,,
,2
1D
d
dDnxdDnx
S
Dnx aa
f
V
where:
x is the x-axis.
n is the sample time, prior to the decimation filter.
D is the decimation rate (DEC_RATE + 1, see Table 109).
fS is the sample rate.
d is the incremental variable in the summation formula.
aX is the x-axis acceleration.
When using the internal sample clock, fS is equal to a nominal
rate of 2000 SPS. For better precision in this measurement,
measure the internal sample rate (fS) using the data ready signal
on the DR pin (DEC_RATE = 0x0000, see Table 108), divide
each delta angle result (from the delta angle output registers) by
the data ready frequency, and multiply it by 2000. Each axis of
the delta velocity measurements has two output data registers.
Figure 43 shows how these two registers combine to support
32-bit, twos complement data format for the delta velocity
measurements along the x-axis. This format also applies to the
y- and z-axes.
X-AXIS DELTA VELOCITY DATA
X_ DELTVEL_OUT X_ DELTVEL_LOW
15436-039
BIT 0 BIT 15BIT 15 BIT 0
Figure 43. Delta Angle Output Data Structure
X-Axis Delta Velocity (X_DELTVEL_LOW and
X_DELTVEL_OUT)
Table 62. X_DELTVEL_LOW Register Definition
Addresses Default Access Flash Backup
0x30, 0x31 Not applicable R No
Table 63. X_DELTVEL_LOW Bit Definitions
Bits Description
[15:0] X-axis delta velocity data; additional resolution bits
Table 64. X_DELTVEL_OUT Register Definition
Addresses Default Access Flash Backup
0x32, 0x33 Not applicable R No
Table 65. X_DELTVEL_OUT Bit Definitions
Bits Description
[15:0] X-axis delta velocity data; twos complement,
±100 m/sec range, 0 m/sec = 0x0000;
1 LSB = 100 m/sec ÷ 215 = ~0.003052 m/sec
The X_DELTVEL_LOW (see Table 62 and Table 63) and
X_DELTVEL_OUT (see Table 64 and Table 65) registers
contain the delta velocity data for the x-axis.
Y-Axis Delta Velocity (Y_DELTVEL_LOW and
Y_DELTVEL_OUT)
Table 66. Y_DELTVEL_LOW Register Definition
Addresses Default Access Flash Backup
0x34, 0x35 Not applicable R No
Table 67. Y_DELTVEL_LOW Bit Definitions
Bits Description
[15:0] Y-axis delta velocity data; additional resolution bits
Table 68. Y_DELTVEL_OUT Register Definition
Addresses Default Access Flash Backup
0x36, 0x37 Not applicable R No
Table 69. Y_DELTVEL_OUT Bit Definitions
Bits Description
[15:0] Y-axis delta velocity data; twos complement,
±100 m/sec range, 0 m/sec = 0x0000;
1 LSB = 100 m/sec ÷ 215 = ~0.003052 m/sec
The Y_DELTVEL_LOW (see Table 66 and Table 67) and
Y_DELTVEL_OUT (see Table 68 and Table 69) registers
contain the delta velocity data for the y-axis.
Z-Axis Delta Velocity (Z_DELTVEL_LOW and
Z_DELTVEL_OUT)
Table 70. Z_DELTVEL_LOW Register Definition
Addresses Default Access Flash Backup
0x38, 0x39 Not applicable R No
Table 71. Z_DELTVEL_LOW Bit Definitions
Bits Description
[15:0] Z-axis delta velocity data; additional resolution bits
Table 72. Z_DELTVEL_OUT Register Definition
Addresses Default Access Flash Backup
0x3A, 0x3B Not applicable R No
Table 73. Z_DELTVEL_OUT Bit Definitions
Bits Description
[15:0] Z-axis delta velocity data; twos complement,
±100 m/sec range, 0 m/sec = 0x0000;
1 LSB = 100 m/sec ÷ 215 = ~0.003052 m/sec
The Z_DELTVEL_LOW (see Table 70 and Table 71) and
Z_DELTVEL_OUT (see Table 72 and Table 73) registers
contain the delta velocity data for the z-axis.
Data Sheet ADIS16475
Rev. C | Page 25 of 37
Delta Velocity Resolution
Table 74 and Table 75 offer various numerical examples that
demonstrate the format of the delta velocity data in both 16-bit
and 32-bit formats.
Table 74. 16-Bit Delta Velocity Data Format Examples
Velocity (m/sec) Decimal Hex Binary
+100 × (215 − 1)/215 +32,767 0x7FFF 0111 1111 1111 1111
+100/214 +2 0x0002 0000 0000 0000 0010
+100/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−100/215 −1 0xFFFF 1111 1111 1111 1111
−100/214 −2 0xFFFE 1111 1111 1111 1110
−100 −32,768 0x8000 1000 0000 0000 0000
Table 75. 32-Bit Delta Velocity Data Format Examples
Velocity (m/sec) Decimal Hex
+100 × (2311)/231 +2,147,483,647 0x7FFFFFFF
+100/230 +2 0x00000002
+100/231 +1 0x00000001
0 0 0x00000000
−100/231 −1 0xFFFFFFFF
−100/230 −2 0xFFFFFFFE
−100 +2,147,483,648 0x80000000
CALIBRATION
The signal chain of each inertial sensor (accelerometers and
gyroscopes) includes the application of unique correction
formulas, which are derived from extensive characterization of
bias, sensitivity, alignment, response to linear acceleration
(gyroscopes), and point of percussion (accelerometer location)
over a temperature range of −40°C to +8C, for each ADIS16475.
These correction formulas are not accessible, but users do have
the opportunity to adjust the bias for each sensor individually
through user accessible registers. These correction factors
follow immediately after the factory derived correction formulas
in the signal chain, which processes at a rate of 2000 Hz when
using the internal sample clock.
Calibration, Gyroscope Bias (XG_BIAS_LOW and
XG_BIAS_HIGH)
Table 76. XG_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x40, 0x41 0x0000 R/W Yes
Table 77. XG_BIAS_LOW Bit Definitions
Bits Description
[15:0] X-axis gyroscope offset correction; lower word
Table 78. XG_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x42, 0x43 0x0000 R/W Yes
Table 79. XG_BIAS_HIGH Bit Definitions
Bits Description
[15:0] X-axis gyroscope offset correction factor, upper word
The XG_BIAS_LOW (see Table 76 and Table 77) and XG_BIAS_
HIGH (see Table 78 and Table 79) registers combine to allow
users to adjust the bias of the x-axis gyroscopes. The data format
examples in Table 12 also apply to the XG_BIAS_HIGH register,
and the data format examples in Table 13 apply to the 32-bit
combination of the XG_BIAS_LOW and XG_BIAS_HIGH
registers. See Figure 44 for an illustration of how these two
registers combine and influence the x-axis gyroscope
measurements.
X-AXIS
GYRO
FACTORY
CALIBRATION
AND
FILTERING
X_GYRO_OUT X_GYRO_LOW
XG_BIAS_HIGH XG_BIAS_LOW
15436-040
Figure 44. User Calibration Signal Path, Gyroscopes
Calibration, Gyroscope Bias (YG_BIAS_LOW and
YG_BIAS_HIGH)
Table 80. YG_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x44, 0x45 0x0000 R/W Yes
Table 81. YG_BIAS_LOW Bit Definitions
Bits Description
[15:0] Y-axis gyroscope offset correction; lower word
Table 82. YG_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x46, 0x47 0x0000 R/W Yes
Table 83. YG_BIAS_HIGH Bit Definitions
Bits Description
[15:0] Y-axis gyroscope offset correction factor, upper word
The YG_BIAS_LOW (see Table 80 and Table 81) and YG_BIAS_
HIGH (see Table 82 and Table 83) registers combine to allow
users to adjust the bias of the y-axis gyroscopes. The data format
examples in Table 12 also apply to the YG_BIAS_HIGH register,
and the data format examples in Table 13 apply to the 32-bit
combination of the YG_BIAS_LOW and YG_BIAS_HIGH
registers. These registers influence the y-axis gyroscope
measurements in the same manner that the XG_BIAS_LOW
and XG_BIAS_HIGH registers influence the x-axis gyroscope
measurements (see Figure 44).
Calibration, Gyroscope Bias (ZG_BIAS_LOW and
ZG_BIAS_HIGH)
Table 84. ZG_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x48, 0x49 0x0000 R/W Yes
Table 85. ZG_BIAS_LOW Bit Definitions
Bits Description
[15:0] Z-axis gyroscope offset correction; lower word
Table 86. ZG_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x4A, 0x4B 0x0000 R/W Yes
ADIS16475 Data Sheet
Rev. C | Page 26 of 37
Table 87. ZG_BIAS_HIGH Bit Definitions
Bits Description
[15:0] Z-axis gyroscope offset correction factor, upper word
Th e Z G_ BIA S_ LOW ( se e Tabl e 84 and Table 85) and ZG_BIAS_
HIGH (see Table 86 and Table 87) registers combine to allow
users to adjust the bias of the z-axis gyroscopes. The data
format examples in Table 12 also apply to the ZG_BIAS_HIGH
register, and the data format examples in Table 13 apply to the
32-bit combination of the ZG_BIAS_LOW and ZG_BIAS_HIGH
registers. These registers influence the z-axis gyroscope
measurements in the same manner that the XG_BIAS_LOW
and XG_BIAS_HIGH registers influence the x-axis gyroscope
measurements (see Figure 44).
Calibration, Accelerometer Bias (XA_BIAS_LOW and
XA_BIAS_HIGH)
Table 88. XA_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x4C, 0x4D 0x0000 R/W Yes
Table 89. XA_BIAS_LOW Bit Definitions
Bits Description
[15:0] X-axis accelerometer offset correction; lower word
Table 90. XA_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x4E, 0x4F 0x0000 R/W Yes
Table 91. XA_BIAS_HIGH Bit Definitions
Bits Description
[15:0] X-axis accelerometer offset correction, upper word
Th e X A _B IAS _L O W ( see Table 88 and Table 89) an d X A_BIAS_
HIGH (see Table 90 and Table 91) registers combine to allow
users to adjust the bias of the x-axis accelerometers. The data
format examples in Table 26 also apply to the XA_BIAS_HIGH
register and the data format examples in Table 27 apply to the 32-
bit combination of the XA_BIAS_LOW and XA_BIAS_HIGH
registers. See Figure 45 for an illustration of how these two registers
combine and influence the x-axis accelerometer measurements.
X-AXIS
ACCL
FACTORY
CALIBRATION
AND
FILTERING
X_ACCL_OUT X_ACCL_LOW
XA_BIAS_HIGH XA_BIAS_LOW
15436-041
Figure 45. User Calibration Signal Path, Accelerometers
Calibration, Accelerometer Bias (YA_BIAS_LOW and
YA_BIAS_HIGH)
Table 92. YA_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x50, 0x51 0x0000 R/W Yes
Table 93. YA_BIAS_LOW Bit Definitions
Bits Description
[15:0] Y-axis accelerometer offset correction; lower word
Table 94. YA_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x52, 0x53 0x0000 R/W Yes
Table 95. YA_BIAS_HIGH Bit Definitions
Bits Description
[15:0] Y-axis accelerometer offset correction, upper word
The YA_BIAS_LOW (see Table 92 and Table 93) and
YA_BIAS_HIGH (see Table 94 and Table 95) registers combine to
allow users to adjust the bias of the y-axis accelerometers. The data
format examples in Table 26 also apply to the YA_BIAS_HIGH
register, and the data format examples in Table 27 apply to the 32-
bit combination of the YA_BIAS_LOW and YA_BIAS_HIGH
registers. These registers influence the y-axis accelerometer
measurements in the same manner that the XA_BIAS_LOW and
XA_BIAS_HIGH registers influence the x-axis accelerometer
measurements (see Figure 45).
Calibration, Accelerometer Bias (ZA_BIAS_LOW and
ZA_BIAS_HIGH)
Table 96. ZA_BIAS_LOW Register Definition
Addresses Default Access Flash Backup
0x54, 0x55 0x0000 R/W Yes
Table 97. ZA_BIAS_LOW Bit Definitions
Bits Description
[15:0] Z-axis accelerometer offset correction; lower word
Table 98. ZA_BIAS_HIGH Register Definition
Addresses Default Access Flash Backup
0x56, 0x57 0x0000 R/W Yes
Table 99. ZA_BIAS_HIGH Bit Definitions
Bits Description
[15:0] Z-axis accelerometer offset correction, upper word
The ZA_BIAS_LOW (see Table 96 and Table 97) and ZA_BIAS_
HIGH (see Table 98 and Table 99) registers combine to allow
users to adjust the bias of the z-axis accelerometers. The data
format examples in Table 26 also apply to the ZA_BIAS_HIGH
register and the data format examples in Table 27 apply to the
32-bit combination of the ZA_BIAS_LOW and ZA_BIAS_HIGH
registers. These registers influence the z-axis accelerometer
measurements in the same manner that the XA_BIAS_LOW
and XA_BIAS_HIGH registers influence the x-axis accelerometer
measurements (see Figure 45).
Filter Control Register (FILT_CTRL)
Table 100. FILT_CTRL Register Definition
Addresses Default Access Flash Backup
0x5C, 0x5D 0x0000 R/W Yes
Table 101. FILT_CTRL Bit Definitions
Bits Description
[15:3] Not used
[2:0] Filter Size Variable B; number of taps in each stage; N = 2B
Data Sheet ADIS16475
Rev. C | Page 27 of 37
The FILT_CTRL register (see Table 100 and Table 101) provides
user controls for the Bartlett window FIR filter (see Figure 22),
which contains two cascaded averaging filters. For example, use
the following sequence to set Register FILT_CTRL, Bits[2:0] =
100, which sets each stage to have 16 taps: 0xCC04 and 0xCD00.
Figure 46 provides the frequency response for several settings in
the FILT_CTRL register.
0
–20
–40
–60
–80
–100
–120
–140
0.001 0.01 0.1 1
MAGNITUDE (dB)
FREQUENCY (
f
/
f
S
N = 2
N = 4
N = 16
N = 64
15436-042
Figure 46. Bartlett Window, FIR Filter Frequency Response
(Phase Delay = N Samples)
Range Identifier (RANG_MDL)
Table 102. RANG_MDL Register Definition
Addresses Default Access Flash Backup
0x5E, 0x5F Not applicable R No
Table 103. RANG_MDL Bit Definitions
Bits Description
[15:3] Not used
[3:2] Gyroscope measurement range
00 = ±125°/sec (ADIS16475-1BMLZ)
01 = ±500°/sec (ADIS16475-2BMLZ)
10 = reserved
11 = ±2000°/sec (ADIS16475-3BMLZ)
[1:0] Reserved, binary value = 11
Miscellaneous Control Register (MSC_CTRL)
Table 104. MSC_CTRL Register Definition
Addresses Default Access Flash Backup
0x60, 0x61 0x00C1 R/W Yes
Table 105. MSC_CTRL Bit Definitions
Bits Description
[15:8] Not used
7 Linear g compensation for gyroscopes (1 = enabled)
6 Point of percussion alignment (1 = enabled)
5 Not used, always set to zero
[4:2] SYNC function setting
111 = reserved (do not use)
110 = reserved (do not use)
101 = pulse sync mode
Bits Description
100 = reserved (do not use)
011 = output sync mode
010 = scaled sync mode
001 = direct sync mode
000 = internal clock mode (default)
1 SYNC polarity (input or output)
1 = rising edge triggers sampling
0 = falling edge triggers sampling
0 DR polarity
1 = active high when data is valid
0 = active low when data is valid
Point of Percussion
Register MSC_CTRL, Bit 6 (see Table 105) offers an on/off control
for the point of percussion alignment function, which maps the
accelerometer sensors to the corner of the package that is closest to
Pin A1 (see Figure 47). The factory default setting in the MSC_
CTRL register activates this function. To turn this function off
while retaining the rest of the factory default settings in the
MSC_CTRL register, set Register MSC_CTRL, Bit 6 = 0, using
the following command sequence on the DIN pin: 0xE081, then
0xE100.
PIN A8
POINT OF
PERCUSSION
PIN A1
15436-043
Figure 47. Point of Percussion Reference Point
Linear Acceleration Effect on Gyroscope Bias
Register MSC_CTRL, Bit 7 (see Table 105) provides an on/off
control for the linear g compensation in the signal calibration
routines of the gyroscope. The factory default contents in the
MSC_CTRL register enable this compensation. To turn the
compensation off, set Register MSC_CTRL, Bit 7 = 0, using
the following sequence on the DIN pin: 0xE041, 0xEF00.
Internal Clock Mode
Register MSC_CTRL, Bits[4:2] (see Table 105), provide five
different configuration options for controlling the clock (fSM;
see Figure 19 and Figure 20), which controls data acquisition
and processing for the inertial sensors. The default setting for
Register MSC_CTRL, Bits[4:2] is 000 (binary), which places the
ADIS16475 in the internal clock mode. In this mode, an internal
clock controls inertial sensor data acquisition and processing at a
nominal rate of 2000 Hz. In this mode, each accelerometer data
update comes from an average of two data samples (sample rate =
4000 Hz).
Output Sync Mode
When Register MSC_CTRL, Bits[4:2] = 011, the ADIS16475
operates in output sync mode, which is the same as internal
ADIS16475 Data Sheet
Rev. C | Page 28 of 37
clock mode with one exception, the SYNC pin pulses when
the internal processor collects data from the inertial sensors.
Figure 48 provides an example of this signal.
SYNC
250µs
500µs
GYROSCOPE AND
ACCELEROMETER
DATA ACQUISITION
ACCELEROMETER
DATA ACQUISITION
15436-044
Figure 48. Sync Output Signal, Register MSC_CTRL, Bits[4:2] = 011
Direct Sync Mode
When Register MSC_CTRL, Bits[4:2] = 001, the ADIS16475
operates in direct sync mode. The signal on the SYNC pin
directly controls the sample clock. In this mode, the internal
processor collects gyroscope data samples on the rising edge of
the clock signal (SYNC pin) and it collects accelerometer data
samples on both rising and falling edges of the clock signal. The
internal processor averages both accelerometer samples (from
rising and falling edges of the clock signal) together to produce
a single data sample. When using this mode, the input clock
signal requires a 50% duty cycle. Therefore, when operating the
ADIS16475 in this mode, the clock signal (SYNC pin) must
have a duty cycle of 50% and a frequency that is within the
range of 1900 Hz to 2100 Hz. The ADIS16475 is capable of
operating when the clock frequency (SYNC pin) is less than
1900 Hz, but with risk of performance degradation, especially
when tracking dynamic inertial conditions (including vibration).
Pulse Sync Mode
When operating in pulse sync mode (Register MSC_CTRL,
Bits[4:2] = 101), the internal processor only collects accelerometer
samples on the leading edge of the clock signal, which enables
the use of a narrow pulse width (see Table 2) in the clock signal on
the SYNC pin. Using pulse sync mode also lowers the bandwidth
on the inertial sensors to 370 Hz. When operating in pulse sync
mode, the ADIS16475 provides the best performance when the
frequency of the clock signal (SYNC pin) is within the range of
1000 Hz to 2100 Hz. The ADIS16475 is capable of operating
when the clock frequency (SYNC pin) is less than 1000 Hz, but
with risk of performance degradation, especially when tracking
dynamic inertial conditions (including vibration).
Scaled Sync Mode
When Register MSC_CTRL, Bits[4:2] = 010, the ADIS16475
operates in scaled sync mode that supports a frequency range of
1 Hz to 128 Hz for the clock signal on the SYNC pin. This mode
of operation is particularly useful when synchronizing the data
processing with a PPS signal from a global positioning system
(GPS) receiver or with a synchronization signal from a video
processing system. When operating in scaled sync mode, the
frequency of the sample clock is equal to the product of the
external clock scale factor, KECSF (from the UP_SCALE register,
see Table 106 and Table 107), and the frequency of the clock
signal on the SYNC pin.
For example, when using a 1 Hz input signal, set UP_SCALE =
0x07D0 (KECSF = 2000 (decimal)) to establish a sample rate of
2000 SPS for the inertial sensors and their signal processing.
Use the following sequence on the DIN pin to configure
UP_SCALE for this scenario: 0xE2D0, then 0xE307.
Table 106. UP_SCALE Register Definition
Addresses Default Access Flash Backup
0x62, 0x63 0x07D0 R/W Yes
Table 107. UP_SCALE Bit Definitions
Bits Description
[15:0] KECSF; binary format
Decimation Filter (DEC_RATE)
Table 108. DEC_RATE Register Definition
Addresses Default Access Flash Backup
0x64, 0x65 0x0000 R/W Yes
Table 109. DEC_RATE Bit Definitions
Bits Description
[15:11] Don’t care
[10:0] Decimation rate, binary format, maximum = 1999
The DEC_RATE register (see Table 108 and Table 109) provides
user control for the averaging decimating filter, which averages and
decimates the gyroscope and accelerometer data; it also extends
the time that the delta angle and the delta velocity track between
each update. When the ADIS16475 operates in internal clock
mode (see Register MSC_CTRL, Bits [4:2], in Table 105), the
nominal output data rate is equal to 2000/(DEC_RATE + 1).
For example, set DEC_RATE = 0x0013 to reduce the output
sample rate to 100 SPS (2000 ÷ 20), using the following DIN pin
sequence: 0xE413, then 0xE500.
Data Update Rate in External Sync Modes
When using the input sync option, in scaled sync mode
(Register MSC_CTRL, Bits[4:2] = 010, see Table 105), the
output data rate is equal to
(fSYNC × KECSF)/(DEC_RATE + 1)
where:
fSYNC is the frequency of the clock signal on the SYNC pin.
KESCF is the value from the UP_SCALE register (see Table 107).
When using direct sync mode and pulse sync mode, KESCF = 1.
Continuous Bias Estimation (NULL_CNFG)
Table 110. NULL_CNFG Register Definition
Addresses Default Access Flash Backup
0x66, 0x67 0x070A R/W Yes
Table 111. NULL_CNFG Bit Definitions
Bits Description
[15:14] Not used
13 Z-axis accelerometer bias correction enable (1 = enabled)
12 Y-axis accelerometer bias correction enable (1 = enabled)
Data Sheet ADIS16475
Rev. C | Page 29 of 37
Bits Description
11 X-axis accelerometer bias correction enable (1 = enabled)
10 Z-axis gyroscope bias correction enable (1 = enabled)
9 Y-axis gyroscope bias correction enable (1 = enabled)
8 X-axis gyroscope bias correction enable (1 = enabled)
[7:4] Not used
[3:0] Time base control (TBC), range: 0 to 12 (default = 10);
tB = 2TBC/2000, time base; tA = 64 × tB, average time
The NULL_CNFG register (see Table 110 and Table 111) provides
the configuration controls for the continuous bias estimator (CBE),
which associates with the bias correction update command in
Register GLOB_CMD, Bit 0 (see Table 113). Register NULL_
CNFG, Bits[3:0], establishes the total average time (tA) for the bias
estimates and Register NULL_CNFG, Bits[13:8], provide the on/off
controls for each sensor. The factory default configuration for the
NULL_CNFG register enables the bias null command for the
gyroscopes, disables the bias null command for the accelerometers,
and sets the average time to ~32 sec.
Global Commands (GLOB_CMD)
Table 112. GLOB_CMD Register Definition
Addresses Default Access Flash Backup
0x68, 0x69 Not applicable W No
Table 113. GLOB_CMD Bit Definitions
Bits Description
[15:8] Not used
7 Software reset
[6:5] Not used
4 Flash memory test
3 Flash memory update
2 Sensor self test
1 Factory calibration restore
0 Bias correction update
The GLOB_CMD register (see Table 112 and Table 113)
provides trigger bits for several operations. Write a 1 to the
appropriate bit in GLOB_CMD to start a particular function.
During the execution of these commands, data production
stops, pulsing stops on the DR pin, and the SPI interface does
not respond to requests. Table 1 provides the execution time for
each GLOB_CMD command.
Software Reset
Use the following DIN sequence to set Register GLOB_CMD,
Bit 7 = 1, which triggers a reset: 0xE880, then 0xE900. This reset
clears all data, and then restarts data sampling and processing.
This function provides a firmware alternative to toggling the
RST pin (see Table 5, Pin F3).
Flash Memory Test
Use the following DIN sequence to set Register GLOB_CMD,
Bit 4 = 1, which tests the flash memory: 0xE810, then 0xE900.
The command performs a CRC computation on the flash memory
(excluding user register locations) and compares it to the original
CRC value, which comes from the factory configuration process. If
the current CRC value does not match the original CRC value,
Register DIAG_STAT, Bit 6 (see Table 10), rises to 1, indicating a
failing result.
Flash Memory Update
Use the following DIN sequence to set Register GLOB_CMD,
Bit 3 = 1, which triggers a backup of all user configurable registers
in the flash memory: 0xE808, then 0xE900. Register DIAG_
STAT, Bit 2 (see Table 10), identifies success (0) or failure (1) in
completing this process.
Sensor Self Test
Use the following DIN sequence to set Register GLOB_CMD,
Bit 2 = 1, which triggers the self test routine for the inertial sensors:
0xE804 and 0xE900. The self test routine uses the following steps
to validate the integrity of each inertial sensor:
1. Measure the output on each sensor.
2. Activate an internal stimulus on the mechanical elements of
each sensor to move them in a predictable manner and
create an observable response in the sensors.
3. Measure the output response on each sensor.
4. Deactivate the internal stimulus on each sensor.
5. Calculate the difference between the sensor measurements
from Step 1 (stimulus is off) and from Step 3 (stimulus is on).
6. Compare the difference with internal pass and fail criteria.
7. Report the pass and fail result to Register DIAG_STAT, Bit 5
(see Table 10).
Motion during the execution of this test can indicate a false
failure.
Factory Calibration Restore
Use the following DIN sequence to set Register GLOB_CMD,
Bit 1 = 1, to restore the factory default settings for the MSC_
CTRL, DEC_RATE, and FILT_CTRL registers and to clear all
user configurable bias correction settings: 0xE802, then 0xE900.
Executing this command results in writing 0x0000 to the
following registers: XG_BIAS_LOW, XG_BIAS_HIGH,
YG_BIAS_LOW, YG_BIAS_HIGH, ZG_BIAS_LOW, ZG_BIAS_
HIGH, XA_BIAS_LOW, XA_BIAS_HIGH, YA_BIAS_LOW,
YA_BIAS_HIGH, ZA_BIAS_LOW, and ZA_BIAS_HIGH.
Bias Correction Update
Use the following DIN pin sequence to set Register GLOB_CMD,
Bit 0 = 1, to trigger a bias correction, using the correction
factors from the CBE (see Table 111): 0xE801, then 0xE900.
Firmware Revision (FIRM_REV)
Table 114. FIRM_REV Register Definition
Addresses Default Access Flash Backup
0x6C, 0x6D Not applicable R No
Table 115. FIRM_REV Bit Definitions
Bits Description
[15:0] Firmware revision, binary coded decimal (BCD) format
ADIS16475 Data Sheet
Rev. C | Page 30 of 37
The FIRM_REV register (see Table 114 and Table 115) provides
the firmware revision for the internal firmware. This register
uses a BCD format, where each nibble represents a digit. For
example, if FIRM_REV = 0x0104, the firmware revision is 1.04.
Firmware Revision Day and Month (FIRM_DM)
Table 116. FIRM_DM Register Definition
Addresses Default Access Flash Backup
0x6E, 0x6F Not applicable R No
Table 117. FIRM_DM Bit Definitions
Bits Description
[15:8] Factory configuration month, BCD format
[7:0] Factory configuration day, BCD format
The FIRM_DM register (see Table 116 and Table 117)
contains the month and day of the factory configuration date.
Register FIRM_DM, Bits[15:8], contain digits that represent the
month of the factory configuration. For example, November is the
11th month in a year and is represented by Register FIRM_DM,
Bits[15:8] = 0x11. Register FIRM_DM, Bits[7:0], contain the
day of factory configuration. For example, the 27th day of the
month is represented by Register FIRM_DM, Bits[7:0] = 0x27.
Firmware Revision Year (FIRM_Y)
Table 118. FIRM_Y Register Definition
Addresses Default Access Flash Backup
0x70, 0x71 Not applicable R No
Table 119. FIRM_Y Bit Definitions
Bits Description
[15:0] Factory configuration year, BCD format
The FIRM_Y register (see Table 118 and Table 119) contains the
year of the factory configuration date. For example, the year,
2017, is represented by FIRM_Y = 0x2017.
Product Identification (PROD_ID)
Table 120. PROD_ID Register Definition
Addresses Default Access Flash Backup
0x72, 0x73 0x405B R No
Table 121. PROD_ID Bit Definitions
Bits Description
[15:0] Product identification = 0x405B
The PROD_ID register (see Table 120 and Table 121) contains
the numerical portion of the device number (16,475). See Figure 32
for an example of how to use a looping read of this register to
validate the integrity of the communication.
Serial Number (SERIAL_NUM)
Table 122. SERIAL_NUM Register Definition
Addresses Default Access Flash Backup
0x74, 0x75 Not applicable R No
Table 123. SERIAL_NUM Bit Definitions
Bits Description
[15:0] Lot specific serial number
Scratch Registers (USER_SCR_1 to USER_SCR_3)
Table 124. USER_SCR_1 Register Definition
Addresses Default Access Flash Backup
0x76, 0x77 Not applicable R/W Yes
Table 125. USER_SCR_1 Bit Definitions
Bits Description
[15:0] User defined
Table 126. USER_SCR_2 Register Definition
Addresses Default Access Flash Backup
0x78, 0x79 Not applicable R/W Yes
Table 127. USER_SCR_2 Bit Definitions
Bits Description
[15:0] User defined
Table 128. USER_SCR_3 Register Definition
Addresses Default Access Flash Backup
0x7A, 0x7B Not applicable R/W Yes
Table 129. USER_SCR_3 Bit Definitions
Bits Description
[15:0] User defined
The USER_SCR_1 (see Table 124 and Table 125), USER_SCR_2
(see Table 126 and Table 127), and USER_SCR_3 (see Table 128
and Table 129) registers provide three locations for the user to
store information. For nonvolatile storage, use the manual flash
memory update command (Register GLOB_CMD, Bit 3, see
Table 113), after writing information to these registers.
Data Sheet ADIS16475
Rev. C | Page 31 of 37
Flash Memory Endurance Counter (FLSHCNT_LOW and
FLSHCNT_HIGH)
Table 130. FLSHCNT_LOW Register Definition
Addresses Default Access Flash Backup
0x7C, 0x7D Not applicable R No
Table 131. FLSHCNT_LOW Bit Definitions
Bits Description
[15:0] Flash memory write counter, low word
Table 132. FLSHCNT_HIGH Register Definition
Addresses Default Access Flash Backup
0x7E, 0x7F Not applicable R No
Table 133. FLSHCNT_HIGH Bit Definitions
Bits Description
[15:0] Flash memory write counter, high word
The FLSHCNT_LOW (see Table 130 and Table 131) and
FLSHCNT_HIGH (see Table 132 and Table 133) registers
combine to provide a 32-bit, binary counter that tracks the
number of flash memory write cycles. In addition to the
number of write cycles, the flash memory has a finite service
lifetime, which depends on the junction temperature. Figure 49
provides guidance for estimating the retention life for the flash
memory at specific junction temperatures. The junction
temperature is approximately 7°C above the case temperature.
600
450
300
150
030 40
RETENTION (Years)
JUNCTION TEMPERATURE (°C)
55 70 85 100 125 135 150
15436-045
Figure 49. Flash Memory Retention
(D ‘9 @ ‘9 {was 000000 0 O O O 03 GO 0 O O 0 Q0 00 Q G * DO DO @009 00000000 ++
ADIS16475 Data Sheet
Rev. C | Page 32 of 37
APPLICATIONS INFORMATION
ASSEMBLY AND HANDLING TIPS
Package Attributes
The ADIS16475 is a multichip module package that has a
44-ball BGA interface. This package has three basic attributes
that influence its handling and assembly to the PCB of the
system: the lid, the substrate, and the BGA pattern. The
material of the lid is a liquid crystal polymer (LCP), and
its nominal thickness is 0.5 mm. The substrate is a laminate
composition that has a nominal thickness of 1.57 mm. The
solder ball material is SAC305, and each ball has a nominal
diameter of 0.75 mm (±0.15 mm). The BGA pattern follows an
8 × 10 array, with 36 unpopulated positions, which simplifies
the escape pattern for the power, ground, and signal traces on
the system PCB.
Assembly Tips
When developing a process to attach the ADIS16475 to a PCB,
consider the following guidelines and insights:
The ADIS16475 is capable of supporting solder reflow
attachment processes, which are in accordance with
J-STD-020E.
Limit device exposure to one pass through the solder
reflow process (no rework).
The hole in the top of the lid (see Figure 50) provides
venting and pressure relief during the assembly process of
the ADIS16475. Keep this hole clear of obstruction while
attaching the ADIS16475 to a PCB.
OPENING IN
PACKAGE LID
15436-046
Figure 50. Pressure Relief Hole
Use no clean flux to avoid exposing the device to cleaning
solvents, which can penetrate the inside of the ADIS16475
through the hole in the lid and be difficult to remove.
When the assembly process requires the use of liquids that
can reach the hole in the lid, use a temporary seal to
prevent entrapment of those liquids inside the cavity.
Manage moisture exposure prior to the solder reflow
processing, in accordance with J-STD-033, Moisture
Sensitivity Level 5.
Avoid exposing the ADIS16475 to mechanical shock
survivability that exceeds the maximum rating of 2000 g
(see Table 3). In standard PCB processing, high speed
handling equipment and panel separation processes often
present the most risk of introducing harmful levels of
mechanical shock survivability.
PCB Layout Suggestions
Figure 51 shows an example of the pad design and layout for the
ADIS16475 on a PCB. This example uses a solder mask opening,
with a diameter of 0.73 mm, around a metal pad that has a
diameter of 0.56 mm. When using a material for the system PCB,
which has similar thermal expansion properties as the substrate
material of the ADIS16475, the system PCB can also use the
solder mask to define the pads that support attachment to the
balls of the ADIS16475. The coefficient of thermal expansion
(CTE) in the substrate of the ADIS16475 is approximately
14 ppm/°C.
ALL DIMENSIONS IN MILLIMETERS
1.27
1.27
0.73
(MASK OPENING)
0.56
(COPPER PAD)
15436-047
Figure 51. Recommend PCB Pattern, Solder Mask Defined Pads
Underfill
Underfill can be a useful technique in managing certain threats
to the integrity of the solder joints of the ADIS16475, including
peeling stress and extended exposure to vibration. When selecting
underfill material and developing an application and curing
process, ensure that the material fills the gap between each surface
(the ADIS16475 substrate and system PCB) and adheres to both
surfaces. The ADIS16475 does not require the use of underfill
materials in applications that do not anticipate exposure to these
types of mechanical stresses and when the CTE of the system
PCB is close to the same value as the CTE of the substrate of the
ADIS16475 (~14 ppm/°C).
Process Validation and Control
These guidelines provide a starting point for developing a process
for attaching the ADIS16475 to a system PCB. Because each
system and situation may present unique requirements for this
attachment process, ensure that the process supports optimal
solder joint integrity, verify that the final system meets all
environmental test requirements, and establish observation and
control strategies for all key process attributes (for example, peak
temperatures, dwell times, and ramp rates).
Data Sheet ADIS16475
Rev. C | Page 33 of 37
POWER SUPPLY CONSIDERATIONS
The ADIS16475 contains 6 μF of decoupling capacitance across
the VDD and GND pins. When the VDD voltage rises from 0 V
to 3.3 V, the charging current for this capacitor bank imposes
the following current profile (in amperes):
 
dt
tdVDD
dt
dVDD
CtIDD 6
106
where:
IDD(t) is the current demand on the VDD pin during the initial
power supply ramp, with respect to time.
C is the internal capacitance across the VDD and GND pins (6 μF).
VDD(t) is the voltage on the VDD pin, with respect to time.
For example, if VDD follows a linear ramp from 0 V to 3.3 V, in
66 μs, the charging current is 300 mA for that timeframe. The
ADIS16475 also contains embedded processing functions that
present transient current demands during initialization or reset
recovery operations. During these processes, the peak current
demand reaches 250 mA and occurs at a time that is approximately
40 ms after VDD reaches 3.0 V (or ~40 ms after initiating a
reset sequence).
SERIAL PORT OPERATION
Maximum Throughput
When operating with the maximum output data (DEC_RATE =
0x0000, as described in Table 109), the maximum SCLK rate
(defined in Table 2), and minimum stall time, the SPI port can
support up to 12, 16-bit register reads in between each pulse of
the data ready signal. Attempting to read more than 12 registers
can result in a datapath overrun error in the DIAG_STAT
register (see Table 10). The serial port stall time (tSTALL) to meet
these requirements must be no more than 10% greater than the
minimum specification for tSTALL in Table 2.
The number of allowable registers reads between each pulse on
the data ready line increases proportionally with the decimation
rate (set by the DEC_RATE register, see Table 109). For example,
when the decimation rate equals 3 (DEC_RATE = 0x0002), the
SPI is able to support up to 36 register reads, assuming
maximum SCLK rate and minimum stall times in the protocol.
Decreasing the SCLK rate and increasing the stall time lowers
the total number of register reads supported by the ADIS16465
before a datapath overrun error occurs.
This limitation of reading 12, 16-bit registers does not impact
the ability of the user to access the full precision of the
gyroscopes and accelerometers if the factory default settings of
DEC_RATE = 0x0000 and FILT_CTRL = 0x0000 are used. In
this case, the data width for the gyroscope and accelerometer
data is 16 bits, and application processors can acquire all
relevant information through the X_GYRO_OUT,
Y_GYRO_OUT, Z_GYRO_OUT, X_ACCEL_OUT,
Y_ACCEL_OUT, and Z_ACCEL_OUT registers. Thirty-two bit
reads of the sensor data do not provide additional precision in
this case. See the Gyroscope Data Width (Digital Resolution)
section and the Accelerometer Data Width (Digital Resolution)
section for more information.
Serial Port SCLK Underrun/Overrun Conditions
The serial port operates in 16-bit segments, and it is critical that
the number of SCLK cycles be equal to an integer multiple of 16
when the CS pin is low. Failure to meet this condition causes the
serial port controller inside of the ADIS16465 to be unable to
correctly receive and respond to new requests.
If too many SCLK cycles are received before the CS pin is
deasserted, the user can recover serial port operation by
asserting CS, providing 17 rising edges on the SCLK line,
deasserting CS, and then attempting to correctly read the
PROD_ID (or other read-only) register on the ADIS16475. The
user should repeat these steps up to a maximum of 15 times
until the correct data is read.
If CS is deasserted before enough SCLK cycles are received, the
user must either power cycle or issue a hard reset (using the
RST pin) to regain SPI port access.
DIGITAL RESOLUTION OF GYROSCOPES AND
ACCELEROMETERS
Gyroscope Data Width (Digital Resolution)
The decimation filter (DEC_RATE register, see Table 109) and
Bartlett window filter (FILT_CTRL register, see Table 101) have
direct influence over the total number of bits in the output data
registers, which contain relevant information. When using the
factory default settings (DEC_RATE = 0x0000, FILT_CTRL =
0x0000) for these filters, the gyroscope data width is 16 bits, which
means that application processors can acquire all relevant
information through the X_GYRO_OUT, Y_GYRO_OUT, and
Z_GYRO_OUT registers.
The X_GYRO_LOW, Y_GYRO_LOW, and Z_GYRO_LOW
registers capture the bit growth that comes from each
accumulation operation in the decimation and Bartlett window
filters. When using these filters (DEC_RATE ≠ 0x0000 and/or
FILT_CTRL ≠ 0x0000), the data width increases by one bit
every time the number of summations (in a filter stage) increases
by a factor of two. For example, when DEC_RATE = 0x0007,
the decimation filter adds eight (7 + 1 = 8, see Table 109)
successive samples together, which causes the data width to
increase by 3 bits (log28 = 3). When FILT_CTRL = 0x0002, both
stages in the Bartlett window filter use four (22 = 4, see Table 101)
summation operations, which increases the data width by two
bits (log24 = 2). When using both DEC_RATE = 0x0007 and
FILT_CTRL = 0x0002, the total bit growth is 7 bits, which
increases the overall data width to 23 bits.
Accelerometer Data Width (Digital Resolution)
The decimation filter (DEC_RATE register, see Table 109) and
Bartlett window filter (FILT_CTRL register, see Table 101) have
direct influence over the total number of bits in the output data
registers, which contain relevant information. When using the
factory default settings (DEC_RATE = 0x0000, FILT_CTRL =
ADIS16475 Data Sheet
Rev. C | Page 34 of 37
0x0000) for these filters, the accelerometer data width is 20 bits.
The X_ACCL_OUT, Y_ACCL_OUT, and Z_ACCL_OUT
registers contain the most significant 16 bits of this data, while
the remaining (least significant) bits are in the upper 4 bits of
the X_ACCL_LOW, Y_ACCL_LOW, and Z_ACCL_LOW
registers. Since the total noise (0.6 mg rms, see Table 1) in the
accelerometer data (DEC_RATE = 0x0000, FILT_CTRL =
0x0000) is greater than the 16-bit quantization noise (0.25 mg ÷
120.5 = 0.072 mg), application processors can acquire all relevant
information through the X_ACCL_OUT, Y_ACCL_OUT, and
Z_ACCL_OUT registers. This enables applications to preserve
optimal performance, while using the burst read (see Figure 31),
which only provides 16-bit data for the accelerometers.
The X_ACCL_LOW, Y_ACCL_LOW, and Z_ACCL_LOW
registers also capture the bit growth that comes from each
accumulation operation in the decimation and Bartlett window
filters. When using these filters (DEC_RATE ≠ 0x0000 and/or
FILT_CTRL ≠ 0x0000), the data width increases by one bit
every time the number of summations (in a filter stage) increases
by a factor of two. For example, when DEC_RATE = 0x0001,
the decimation filter adds two (1 + 1 = 2, see Table 109) successive
samples together, which causes the data width to increase by 1
bit (log22 = 1). When FILT_CTRL = 0x0001, both stages in the
Bartlett window filter add two (21 = 2, see Table 101) successive
samples together, which increases the data width by 1 bit (log22
= 1) as well. When using both DEC_RATE = 0x0001 and
FILT_CTRL = 0x0001, the total bit growth is 3 bits, which
increases the overall data width to 23 bits.
EVALUATION TOOLS
Breakout Boards
The ADIS16475 has three difference breakout boards, which
provide a simple way to connect an ADIS16475 model and an
existing embedded processor platform. Table 134 provides a list
of the model numbers for each breakout board, along with the
ADIS16475 model that is on each breakout board.
Table 134. Breakout Board Models
Breakout Board Model ADIS16475 Model
ADIS16475-1/PCBZ ADIS16475-1BMLZ
ADIS16475-2/PCBZ ADIS16475-2BMLZ
ADIS16475-3/PCBZ ADIS16475-3BMLZ
The electrical interface (J1) on each breakout board comes from
a dual row, 2 mm pitch, 16-pin interface, which supports standard
ribbon cabling (1 mm pitch). Table 135 provides the J1 pin assign-
ments, which support direct connection with an embedded
processor board using standard ribbon cables. Although each
case may present its own set of sensitivities (such as electromag-
netic interference (EMI)), these boards can typically support
reliable communication over ribbon cables up to 20 cm in length.
Table 135. J1 Pin Assignments, Breakout Board
J1 Pin Number Signal Function
1 RST Reset
2 SCLK SPI
3 CS SPI
4 DOUT SPI
5 NC No connect
6 DIN SPI
7 GND Ground
8 GND Ground
9 GND Ground
10 VDD Power, 3.3 V
11 VDD Power, 3.3 V
12 VDD Power, 3.3 V
13 DR Data ready
14 SYNC Input clock
15 NC No connect
16 NC No connect
Figure 52 provides a top level view of the breakout board, including
dimensional locations for all the key mechanical features, such
as the mounting holes and the 16-pin header. Figure 53 provides
an electrical schematic for this breakout board. For additional
information, refer to the ADIS1647x/PCB Wiki Guide.
R a 4; SEGE‘ES TI |._ -*‘ F—
Data Sheet ADIS16475
Rev. C | Page 35 of 37
ADIS1647X/PCB
BREAKOUT BOARD
08-045113rA
J1
TFD2
ML/BEL 11/14/16 TFD1
*
5.125mm
5.125mm
3.625mm
6.03mm
33.25mm
16.99mm
16.26mm
30.07mm
15436-048
Figure 52. Top Level View of the Breakout Board
VDD
VDD
VDD
C7
D6
H1
K6
J5
J4
VDD
VDD
ADIS16475AMLZ
DUT1
VDD
VDD
NCGNDGND
GND SCLK SCLK
GND
RST VDD VDD
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
A1
A2
A3
A4
A5
A6
A7
A8
B8
B3
B4
B5
B6
J6
J3
H3
H6
E3
C3
G3
G6
F6
F3
D3
K8
K3
K1
J7
J2
H8
G7
G2
F8
F1
E7
E6
E2
C6
C2
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
DIN DOUT DOUTDIN
CS DR DR
SYNC SYNC
CS
RST
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
GND
VDD
J1
SCLK
DOUT
CS
DIN
GND
DR
NC
GND
VDD
SYNC
RST
HIROSE
A3-16-PA-2SV(71)
15436-049
Figure 53. Breakout Board Schematic
ADIS16475 Data Sheet
Rev. C | Page 36 of 37
PC-Based Evaluation, EVAL-ADIS2
In addition to supporting quick prototype connections between
the ADIS16475 and an embedded processing system, J1 on the
breakout boards also connects directly to J1 on the EVAL-ADIS2
evaluation system. When used in conjunction with the IMU
Evaluation Software for the EVAL-ADISX Platforms, the EVAL-
ADIS2 provides a simple, functional test platform that allows
users to configure and collect data from the ADIS16475 models.
TRAY DRAWING
The ADIS16475 parts are shipped in the tray shown in Figure 54.
15436-100
NOTES:
1. MATERIAL IS MPPO.
2.
TOLERANCES ARE
x.x =
± 0.25
x.xx
= ± 0.13
UNLESS OTHE RWISE SPECITIED.
3. ESD
SURFACE RESISTIVIT Y
10
5
TO 10
11
Ω/SQ.
322.60 REF
11.95 BSC
22.00 BSC
16.00
BSC
315.00
255.30
2.54
34.30 25.40
17.90
21.40
135.90
92.10
12.70
112.25
112.00
111.75
272.05
271.80
271.55
TOP VIEW
SIDE VIEW
14.50 BSC
DETAIL A
DETAIL A
A
A
B
B
7.90
11.10
SECTION A-A
15.43
15.35
15.27
SECTION B-B
11.43
11.35
11.27
DETAIL B
DETAIL C
DETAIL C
DETAIL B
30°
±
3.50
2.00
1.30
2.50 3.80
0.76
R 4.75
C 3.00 × 0.45°
Figure 54. Drawing of Shipping Tray
I: ANALOG DEVICES
Data Sheet ADIS16475
Rev. C | Page 37 of 37
PACKAGING AND ORDERING INFORMATION
OUTLINE DIMENSIONS
0
6-22-2017-B
PKG-005267
A1 BALL
CORNER INDICATOR
*Including Lable
Thickness
SEATING
PLANE
TOP VIEW
END VIEW
BOTTOM VIEW
11.25
11.00
10.75
15.25
15.00
14.75
11.350
11.000
*10.475
1.055
BSC
1.785
BSC
1.270
BSC
1.270
BSC
0.900
Ø0.750
0.600
0.90
MAX
Figure 55. 44-Ball Ball Grid Array Module [BGA]
(ML-44-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option
ADIS16475-1BMLZ −40°C to +105°C 44-Ball Ball Grid Array Module [BGA] ML-44-1
ADIS16475-2BMLZ −40°C to +105°C 44-Ball Ball Grid Array Module [BGA] ML-44-1
ADIS16475-3BMLZ −40°C to +105°C 44-Ball Ball Grid Array Module [BGA] ML-44-1
ADIS16475-1/PCBZ ADIS16475-1 Breakout Board
ADIS16475-2/PCBZ ADIS16475-2 Breakout Board
ADIS16475-3/PCBZ ADIS16475-3 Breakout Board
1 Z = RoHS Compliant Part.
©2017–2019 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D15436-0-4/19(C) www.analog.com/ADIS16475

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