PI33xx-x1 Datasheet by Vicor Corporation

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fl VICOR VICDR
8V to 36VIN, 15A Cool-Power ZVS Buck Regulator
Cool-Power®
ZVS Switching Regulators
PI33xx-x1
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 1 of 27 11/2016
Product Description
The PI33xx-x1 is a family of high efficiency, wide input range DC-
DC ZVS-Buck regulators integrating controller, power switches,
and support components all within a high density System-in-
Package (SiP). The integration of a high performance Zero-
Voltage Switching (ZVS) topology, within the PI33xx-x1 series
increases point of load performance providing best in class power
efficiency. The PI33xx-x1 requires only an external inductor and
minimal capacitors to form a complete DC-DC switching mode
Buck Regulator.
The ZVS architecture also enables high frequency operation while
minimizing switching losses and maximizing efficiency. The high
switching frequency operation reduces the size of the external
filtering components, improves power density, and enables very
fast dynamic response to line and load transients. The PI33xx-x1
series sustains high switching frequency all the way up to the
rated input voltage without sacrificing efficiency and, with its
20ns minimum on-time, supports large step down conversions
up to 36VIN.
Features & Benefits
High Efficiency ZVS-Buck Topology
Wide input voltage range of 8V to 36V
Very-Fast transient response
High accuracy pre-trimmed output voltage
User adjustable soft-start & tracking
Power-up into pre-biased load (select versions)
Parallel capable with single wire current sharing
Input Over / Undervoltage Lockout (OVLO/UVLO)
Output Overvoltage Protection (OVP)
Overtemperature Protection (OTP)
Fast and slow current limits
-40°C to 125°C operating range (TJ)
Optional I2C* functionality & programmability:
VOUT margining
Fault reporting
Enable and SYNCI pin polarity
Phase delay (interleaving multiple regulators)
Applications
High efficiency systems
Computing, Communications, Industrial,
Automotive Equipment
High voltage battery operation
Package Information
10mm x 14mm x 2.6mm LGA SiP
Device Output Voltage IOUT Max
Set Range
PI3311-x1-LGIZ 1.0V 1.0 to 1.4V 15A
PI3318-x1-LGIZ 1.8V 1.4 to 2.0V 15A
PI3312-x1-LGIZ 2.5V 2.0 to 3.1V 15A
PI3301-x1-LGIZ 3.3V 2.3 to 4.1V 15A
Table 1 – PI33xx-x1 portfolio
* I2C is a trademark of NXP Semiconductors
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 2 of 27 11/2016
PI33xx-x1
Contents
Order Information 3
Absolute Maximum Ratings 4
Functional Block Diagram 4
Pin Description 5
Package Pin-Out 5
PI3311-x1-LGIZ (1.0VOUT) Electrical Characteristics 6
PI3318-x1-LGIZ (1.8VOUT) Electrical Characteristics 9
PI3312-x1-LGIZ (2.5VOUT) Electrical Characteristics 12
PI3301-x1-LGIZ (3.3VOUT) Electrical Characteristics 15
Functional Description 18
ENABLE (EN) 18
Remote Sensing 18
Switching Frequency Synchronization 18
Soft-Start 18
Output Voltage Trim 18
Output Current Limit Protection 19
Input Undervoltage Lockout 19
Input Overvoltage Lockout 19
Output Overvoltage Protection 19
Overtemperature Protection 19
Pulse Skip Mode (PSM) 19
Variable Frequency Operation 19
Parallel Operation 20
I2C Interface Operation 20
Application Description 21
Output Voltage Trim 21
Soft-Start Adjust and Tracking 22
Inductor Pairing 22
Layout Guidelines 23
Recommended PCB Footprint and Stencil 24
LGIZ Package Drawing 25
Revision History 26
Product Warranty 27
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 3 of 27 11/2016
PI33xx-x1
Order Information
Cool-Power Output Range IOUT Max Package Transport
Media
Set Range
PI3311-01-LGIZ 1.0V 1.0 to 1.4V 15A 10mm x 14mm 123-pin LGA TRAY
PI3318-01-LGIZ 1.8V 1.4 to 2.0V 15A 10mm x 14mm 123-pin LGA TRAY
PI3312-01-LGIZ 2.5V 2.0 to 3.1V 15A 10mm x 14mm 123-pin LGA TRAY
PI3301-01-LGIZ 3.3V 2.3 to 4.1V 15A 10mm x 14mm 123-pin LGA TRAY
I2C Functionality & Programmability
Cool-Power Output Range IOUT Max Package Transport
Media
Set Range
PI3311-21-LGIZ 1.0V 1.0 to 1.4V 15A 10mm x 14mm 123-pin LGA TRAY
PI3318-21-LGIZ 1.8V 1.4 to 2.0V 15A 10mm x 14mm 123-pin LGA TRAY
PI3312-21-LGIZ 2.5V 2.0 to 3.1V 15A 10mm x 14mm 123-pin LGA TRAY
PI3301-21-LGIZ 3.3V 2.3 to 4.1V 15A 10mm x 14mm 123-pin LGA TRAY
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 4 of 27 11/2016
PI33xx-x1
Absolute Maximum Ratings
Functional Block Diagram
PGND
SGND
SYNCO
PGD
Q1 Q2
ADR0
SDA
VCC
ADR1
EN
SYNCI
TRK
EAO
ADJ
VS1
Power
Control
InterfaceMemory
+
-
VOUT
REM
SCL
R4
R2
VOUT
R1
ZVS Control
1V
VIN
VIN
Notes: At 25°C ambient temperature. Stresses beyond these limits may cause permanent damage to the device. Operation at these conditions or condi-
tions beyond those listed in the Electrical Specifications table is not guaranteed. All voltage nodes are referenced to PGND unless otherwise noted.
Test conditions are per the specifications within the individual product electrical characteristics.
Simplified Block Diagram (I2C pins SCL, SDA, ADR0, and ADR1 only active for PI33xx-21 device versions)
Name Rating
VIN -0.7V to 36V
VS1 -0.7V to 36VDC
SGND 100mA
PGD, SYNCO, SYNCI, EN, EAO, ADJ, TRK, ADR1, ADR2, SCL, SDA -0.3V to 5.5V / 5mA
VOUT , REM
PI3311-x1-LGIZ -0.3V to 5.5V
PI3318-x1-LGIZ -0.5V to 9V
PI3312-x1-LGIZ -0.8V to 13V
PI3301-x1-LGIZ -1.0V to 18V
Storage Temperature -65°C to 150°C
Operating Junction Temperature -40°C to 125°C
Soldering Temperature for 20 seconds 245°C
ESD Rating 2kV HBM
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 5 of 27 11/2016
PI33xx-x1
Package Pin-Out
Pin Description
PGD
EAO
EN
REM
VS1
Block 4
VIN
Block 3
PGND
Block 2
SYNCI
SYNCO
VDR
SGND
ADJ
TRK
SDA
SCL
ADR0
ADR1
K
J
H
G
F
E
D
C
B
A
13125431 14210987611
SGND
Block 1
VOUT
Block 5
NC
Block 1: B2-4, C2-4, D2-3, E2-3, F1-3, G2-3, H2-3, J1-3, K1-2
Block 2: A8-10, B8-10, C8-10, D8-10, E4-10,
F4-10, G4-10, H4-10, J4-10, K6-10
Block 3: G12-14, H12-14, J12-14, K12-14
Block 4: A12-14, B12-14, C12-14, D12-14, E12-14
Block 5: A6-7, B6-7, C6-7, D6-7
Pin Name Number Description
SGND Block 1 Signal Ground: Internal logic ground for EA, TRK, SYNCI, SYNCO, ADJ and I2C (options) communication
returns. SGND and PGND are star connected within the regulator package.
PGND Block 2 Power Ground: VIN and VOUT power returns.
VIN Block 3 Input Voltage: and sense for UVLO, OVLO and feed forward ramp.
VOUT Block 5 Output Voltage: and sense for power switches and feed-forward ramp.
VS1 Block 4 Switching Node: and ZVS sense for power switches.
PGD A1 Parallel Good: Used for parallel timing management intended for lead regulator.
EAO A2 Error Amp Output: External connection for additional compensation and current sharing.
EN A3 Enable Input: Regulator enable control. Asserted high or left floating – regulator enabled;
Asserted low, regulator output disabled. Polarity is programmable via I2C interface.
REM A5 Remote Sense: High side connection. Connect to output regulation point.
ADJ B1 Adjust Input: An external resistor may be connected between ADJ pin and SGND or VOUT
to trim the output voltage up or down.
TRK C1 Soft-start and Track Input: An external capacitor may be connected between TRK pin
and SGND to decrease the rate of rise during soft-start.
NC A4 No Connect: Leave pins floating.
VDR K3 VDR can only be used for ADR0 and ADR1 pull up reference voltage.
No other external loading is permitted.
SYNCO K4 Synchronization Output: Outputs a low signal for ½ of the minimum period for
synchronization of other converters.
SYNCI K5 Synchronization Input: Synchronize to the falling edge of external clock frequency.
SYNCI is a high impedance digital input node and should always be connected to SGND when not in use.
SDA D1 Data Line: Connect to SGND for PI33xx-01 and PI33xx-11. For use with PI33xx-21 only.
SCL E1 Clock Line: Connect to SGND for PI33xx-01. For use with PI33xx-21 only.
ADR1 H1 Tri-state Address: No connect for PI33xx-01. For use with PI33xx-21 only.
ADR0 G1 Tri-state Address: No connect for PI33xx-01. For use with PI33xx-21 only.
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 6 of 27 11/2016
PI33xx-x1
PI3311-x1-LGIZ (1.0VOUT) Electrical Characteristics
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 85nH [1]
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
Parameter Symbol Conditions Min Typ Max Unit
Input Specifications
Input Voltage VIN_DC Minimum 1mA load required 8 24 36 V
Input Current IIN_DC VIN = 24V, TC = 25°C, IOUT =15A 740 mA
Input Current At Output Short
(fault condition duty cycle) IIN_Short [2] 25 mA
Input Quiescent Current IQ_VIN
Disabled 2.0 mA
Enabled (no load) 2.5 mA
Input Voltage Slew Rate VIN_SR 1 V/μs
Output Specifications
Output Voltage Total Regulation VOUT_DC [2] 0.987 1.0 1.013 V
Output Voltage Trim Range VOUT_DC [3] 1.0 1.4 V
Line Regulation VOUT (VIN) @25°C, 8V < VIN < 36V 0.10 %
Load Regulation VOUT (IOUT) @25°C, 0.5A < IOUT < 15A 0.10 %
Output Voltage Ripple VOUT_AC IOUT = 5A, COUT = 8 x 100μF, 20MHz BW [4] 45 mVp-p
Continuous Output
Current Range IOUT_DC [5] 0.001 15 A
Current Limit IOUT_CL 18.0 A
Protection
VIN UVLO Start Threshold VUVLO_START 7.10 7.60 8.00 V
VIN UVLO Stop Threshold VUVLO_STOP 6.80 7.25 7.60 V
VIN UVLO Hysteresis VUVLO_HYS 0.35 V
VIN OVLO Start Threshold VOVLO_START 36.1 37.6 V
VIN OVLO Stop Threshold VOVLO_STOP 37.0 38.4 V
VIN OVLO Hysteresis VOVLO_HYS 0.8 V
VIN UVLO/OVLO Fault Delay Time tf_DLY Number of the switching frequency cycles 128 Cycles
VIN UVLO/OVLO Response Time tf500 ns
Output Overvoltage Protection VOVP Above VOUT 20 %
Overtemperature
Fault Threshold TOTP [2] 130 135 140 °C
Overtemperature
Restart Hysteresis TOTP_HYS 30 °C
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 7 of 27 11/2016
PI33xx-x1
PI3311-x1-LGIZ (1.0VOUT) Electrical Characteristics (Cont.)
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 85nH [1]
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
Parameter Symbol Conditions Min Typ Max Unit
Timing
Switching Frequency fS[6] 500 kHz
Fault Restart Delay tFR_DLY 30 ms
Sync In (SYNCI)
Synchronization Frequency
Range fSYNCI Relative to set switching frequency [3] 50 110 %
SYNCI Threshold VSYNCI 2.5 V
Sync Out (SYNCO)
SYNCO High VSYNCO_HI Source 1mA 4.5 V
SYNCO Low VSYNCO_LO Sink 1mA 0.5 V
SYNCO Rise Time tSYNCO_RT 20pF load 10 ns
SYNCO Fall Time tSYNCO_FT 20pF load 10 ns
Soft-Start And Tracking
TRK Active Input Range VTRK Internal reference tracking range 0 1.04 V
TRK Max Output Voltage VTRK_MAX 1.2 V
TRK Disable Threshold VTRK_OV 20 40 60 mV
Charge Current (Soft-Start) ITRK -70 -50 -30 μA
Discharge Current (Fault) ITRK_DIS 6.8 mA
Soft-Start Time tSS CTRK = 0μF 2.2 ms
Enable
High Threshold VEN_HI 0.9 1 1.1 V
Low Threshold VEN_LO 0.7 0.8 0.9 V
Threshold Hysteresis VEN_HYS 100 200 300 mV
Enable Pull-Up Voltage
(floating, unfaulted) VEN_PU With positive logic EN polarity 2 V
Enable Pull-Down Voltage
(floating, faulted) VEN_PD With negative logic EN polarity 0 V
Source Current IEN_SO With positive logic EN polarity -50 μA
Sink Current IEN_SK With negative logic EN polarity 50 μA
CH2 ; CH3 CH2 VOL”: 1DDmV/div Tlmebase' mops/div CH3 IO“: 5A1div l CH2 ? CH2 VouT? SODmVIdiv Tlmebase 2ms/div CH2 Vow: SOmVIdiv Turnebase: ans/div CH4 II". SOOmA/div l \ x... \ : \§S§ CH2 : CH2 Vow: SOmVIdiv 'l'Imebase: Zysldiv VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
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PI33xx-x1
Figure 2 — Short Circuit Test
Figure 1 — Efficiency at 25°C
Figure 3 — Switching Frequency vs. Load Current
Figure 4 — Transient Response 7.5A to 15A, at 5A/µs;
24VIN to 1.0VOUT, COUT = 8 x 100µF Ceramic
Figure 6 — Output Ripple 24VIN, 1.0VOUT at 7A;
COUT = 8 x 100µF Ceramic
Figure 5 — Output Ripple 24VIN, 1.0VOUT at 15A;
COUT = 8 x 100µF Ceramic
PI3311-x1-LGIZ (1.0VOUT) Electrical Characteristics (Cont.)
Load Current (A)
Frequency (kHz)
VIN = 12VVIN = 8V
2
0
100
200
300
400
500
600
3456789101213141511
VIN = 24VV
IN = 36V
Load Current (A)
Efficiency (%)
VIN = 12VVIN = 8V
50
55
65
75
85
95
60
70
80
90
100
012345678910 11 12 13 14 15
VIN = 24VV
IN = 36V
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 9 of 27 11/2016
PI33xx-x1
PI3318-x1-LGIZ (1.8VOUT) Electrical Characteristics
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 125nH [1]
Parameter Symbol Conditions Min Typ Max Unit
Input Specifications
Input Voltage VIN_DC 8 24 36 V
Input Current IIN_DC VIN = 24V, TC = 25°C, IOUT =10A 835 A
Input Current At Output Short
(fault condition duty cycle) IIN_Short [2] 20 mA
Input Quiescent Current IQ_VIN
Disabled 2.0 mA
Enabled (no load) 2.5
Input Voltage Slew Rate VIN_SR [2] 1 V / μs
Output Specifications
Output Voltage Total Regulation VOUT_DC [2] 1.773 1.8 1.827 V
Output Voltage Trim Range VOUT_DC [3] 1.4 2.0 V
Line Regulation VOUT (VIN) @25°C, 8V < VIN < 36V 0.10 %
Load Regulation VOUT (IOUT) @25°C, 0.5A < IOUT < 15A 0.10 %
Output Voltage Ripple VOUT_AC IOUT = 5A, COUT = 6 x 100μF, 20MHz BW [4] 30 mVp-p
Continuous Output
Current Range IOUT_DC [5] 0 15 A
Current Limit IOUT_CL 18.0 A
Protection
VIN UVLO Start Threshold VUVLO_START 7.10 7.60 8.00 V
VIN UVLO Stop Threshold VUVLO_STOP 6.80 7.25 7.60 V
VIN UVLO Hysteresis VUVLO_HYS 0.35 V
VIN OVLO Start Threshold VOVLO_START 36.1 37.6 V
VIN OVLO Stop Threshold VOVLO_STOP 37.0 38.4 V
VIN OVLO Hysteresis VOVLO_HYS 0.8 V
VIN UVLO/OVLO Fault Delay Time tf_DLY Number of the switching frequency cycles 128 Cycles
VIN UVLO/OVLO Response Time tf500 ns
Output Overvoltage Protection VOVP Above VOUT 20 %
Overtemperature
Fault Threshold TOTP [2] 130 135 140 °C
Overtemperature
Restart Hysteresis TOTP_HYS 30 °C
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 10 of 27 11/2016
PI33xx-x1
PI3318-x1-LGIZ (1.8VOUT) Electrical Characteristics (Cont.)
Unless otherwise specified: -40°C < TJ < 125°C, VIN =24V, L1 = 125nH [1]
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
Parameter Symbol Conditions Min Typ Max Unit
Timing
Switching Frequency fS[6] 550 kHz
Fault Restart Delay tFR_DLY 30 ms
Sync In (SYNCI)
Synchronization Frequency
Range fSYNCI Relative to set switching frequency [3] 50 110 %
SYNCI Threshold VSYNCI 2.5 V
Sync Out (SYNCO)
SYNCO High VSYNCO_HI Source 1mA 4.5 V
SYNCO Low VSYNCO_LO Sink 1mA 0.5 V
SYNCO Rise Time tSYNCO_RT 20pF load 10 ns
SYNCO Fall Time tSYNCO_FT 20pF load 10 ns
Soft-Start And Tracking
TRK Active Input Range VTRK Internal reference tracking range 0 1.04 V
TRK Max Output Voltage VTRK_MAX 1.2 V
TRK Disable Threshold VTRK_OV 20 40 60 mV
Charge Current (Soft-Start) ITRK -70 -50 -30 μA
Discharge Current (Fault) ITRK_DIS 6.8 mA
Soft-Start Time tSS CTRK = 0μF 2.2 ms
Enable
High Threshold VEN_HI 0.9 1 1.1 V
Low Threshold VEN_LO 0.7 0.8 0.9 V
Threshold Hysteresis VEN_HYS 100 200 300 mV
Enable Pull-Up Voltage
(floating, unfaulted) VEN_PU 2 V
Enable Pull-Down Voltage
(floating, faulted) VEN_PD 0 V
Source Current IEN_SO -50 μA
Sink Current IEN_SK 50 μA
CH3 CH2 fl — CH3 VOL": 1DDmV/div CH2 Io“; IDA/div Timebase: aoysldiv CH3 VOL": 500mV/div CH2 II". 1Aldiv Tlmebasa 1ms/div CH3 Vow: 20mV/div Timebase: 2ysldiv / / // // CH3 \WNW'NL’VW‘XRRM CH3 Vow: 20mV/div Tlmebase: Zysldiv VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
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PI33xx-x1
Figure 8 — Short Circuit Test
Figure 7 — Efficiency at 25°C
Figure 9 — Switching Frequency vs. Load Current
Figure 10 — Transient Response 7A to 15A, at 5A/µs;
24VIN to 1.8VOUT, COUT = 8 x 100µF Ceramic
Figure 12 — Output Ripple 24VIN, 1.8VOUT at 7.5A;
COUT = 8 x 100µF Ceramic
Figure 11 — Output Ripple 24VIN, 1.8VOUT at 15A;
COUT = 8 x 100µF Ceramic
PI3318-x1-LGIZ (1.8VOUT) Electrical Characteristics (Cont.)
Load Current (A)
Frequency (kHz)
VIN = 12VVIN = 8V
21
0
100
200
300
400
500
600
3456789101213141511
VIN = 24VV
IN = 36V
Load Current (A)
Efficiency (%)
VIN = 12VVIN = 8V
50
55
65
75
85
95
60
70
80
90
100
012345678910 11 12 13 14 15
VIN = 24VV
IN = 36V
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 12 of 27 11/2016
PI33xx-x1
PI3312-x1-LGIZ (2.5VOUT) Electrical Characteristics
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 125nH [1]
Parameter Symbol Conditions Min Typ Max Unit
Input Specifications
Input Voltage VIN_DC [7] 8 24 36 V
Input Current IIN_DC VIN = 24V, TC = 25°C, IOUT = 15A 1.7 A
Input Current At Output Short
(fault condition duty cycle) IIN_Short [2] 60 mA
Input Quiescent Current IQ_VIN
Disabled 2.0 mA
Enabled (no load) 2.5
Input Voltage Slew Rate VIN_SR 1 V / μs
Output Specifications
Output Voltage Total Regulation VOUT_DC [2] 2.465 2.500 2.535 V
Output Voltage Trim Range VOUT_DC [3] [7] 2.0 2.5 3.1 V
Line Regulation VOUT (VIN) @25°C, 8V < VIN < 36V 0.10 %
Load Regulation VOUT (IOUT) @25°C, 0.5A < IOUT < 15A 0.10 %
Output Voltage Ripple VOUT_AC IOUT = 5A, COUT = 4 x 100μF, 20MHz BW [4] 28 mVp-p
Continuous Output
Current Range IOUT_DC [5] [7] 0 15 A
Current Limit IOUT_CL 18.0 A
Protection
VIN UVLO Start Threshold VUVLO_START 7.10 7.60 8.00 V
VIN UVLO Stop Threshold VUVLO_STOP 6.80 7.25 7.60 V
VIN UVLO Hysteresis VUVLO_HYS 0.35 V
VIN OVLO Start Threshold VOVLO_START 36.1 37.6 V
VIN OVLO Stop Threshold VOVLO_STOP 37.0 38.4 V
VIN OVLO Hysteresis VOVLO_HYS 0.8 V
VIN UVLO/OVLO Fault Delay Time tf_DLY Number of the switching frequency cycles 128 Cycles
VIN UVLO/OVLO Response Time tf500 ns
Output Overvoltage Protection VOVP Above VOUT 20 %
Overtemperature
Fault Threshold TOTP [2] 130 135 140 °C
Overtemperature
Restart Hysteresis TOTP_HYS 30 °C
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
[7] Minimum 5V between VIN–VOUT must be maintained or a minimum load of 1mA required.
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 13 of 27 11/2016
PI33xx-x1
PI3312-x1-LGIZ (2.5VOUT) Electrical Characteristics (Cont.)
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 125nH [1]
Parameter Symbol Conditions Min Typ Max Unit
Timing
Switching Frequency fS[6] 650 kHz
Fault Restart Delay tFR_DLY 30 ms
Sync In (SYNCI)
Synchronization Frequency
Range fSYNCI Relative to set switching frequency [3] 50 110 %
SYNCI Threshold VSYNCI 2.5 V
Sync Out (SYNCO)
SYNCO High VSYNCO_HI Source 1mA 4.5 V
SYNCO Low VSYNCO_LO Sink 1mA 0.5 V
SYNCO Rise Time tSYNCO_RT 20pF load 10 ns
SYNCO Fall Time tSYNCO_FT 20pF load 10 ns
Soft-Start And Tracking
TRK Active Input Range VTRK Internal reference tracking range 0 1.04 V
TRK Max Output Voltage VTRK_MAX 1.2 V
TRK Disable Threshold VTRK_OV 20 40 60 mV
Charge Current (Soft-Start) ITRK -70 -50 -30 μA
Discharge Current (Fault) ITRK_DIS 6.8 mA
Soft-Start Time tSS CTRK = 0μF 2.2 ms
Enable
High Threshold VEN_HI 0.9 1 1.1 V
Low Threshold VEN_LO 0.7 0.8 0.9 V
Threshold Hysteresis VEN_HYS 100 200 300 mV
Enable Pull-Up Voltage
(floating, unfaulted) VEN_PU 2 V
Enable Pull-Down Voltage
(floating, faulted) VEN_PD 0 V
Source Current IEN_SO -50 μA
Sink Current IEN_SK 50 μA
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
[7] Minimum 5V between VIN–VOUT must be maintained or a minimum load of 1mA required.
CHI —— CH4 _ . .— .— _ _ _ _ CH1 vom- zcumwdiv nmenase megs/aw CH4 low' 5A1d|v o "- CH1 —— 1 ' CHI . Bab—— WW CH4 4 — CH1 Vom' 1V/div Tlmebase sows/aw CH1 Vour' somwdiv Tlmebase lays/div CH4I.N-1A/dw 3 CH! WMAWAMWMA CH1 vour- 50mV/div Tlmebase 4ysldlv VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 14 of 27 11/2016
PI33xx-x1
Figure 14 — Short Circuit Test
Figure 13 — Efficiency at 25°C
Figure 15 — Switching Frequency vs. Load Current
Figure 16 — Transient Response 7.5A to 15A, at 5A/µs;
24VIN to 2.5VOUT, COUT = 8 x 100µF Ceramic
Figure 18 — Output Ripple 24VIN, 2.5VOUT at 7.5A
COUT = 8 x 100µF Ceramic
Figure 17 — Output Ripple 24VIN, 2.5VOUT at 15A
COUT = 8 x 100µF Ceramic
PI3312-x1-LGIZ (2.5VOUT) Electrical Characteristics (Cont.)
Load Current (A)
Frequency (kHz)
VIN = 12VVIN = 8V
21
0
100
200
300
400
500
600
700
3456789101213141511
VIN = 24VV
IN = 36V
Load Curent (A)
Efficiency (%)
VIN = 12VVIN = 8V
50
55
65
75
85
95
60
70
80
90
100
012345678910 11 12 13 14 15
VIN = 24VV
IN = 36V
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 15 of 27 11/2016
PI33xx-x1
PI3301-x1-LGIZ (3.3VOUT) Electrical Characteristics
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 155nH [1]
Parameter Symbol Conditions Min Typ Max Unit
Input Specifications
Input Voltage VIN_DC [7] 8 24 36 V
Input Current IIN_DC VIN = 24V, TC = 25°C, IOUT =15A 2.25 A
Input Current At Output Short
(fault condition duty cycle) IIN_Short [2] 75 mA
Input Quiescent Current IQ_VIN
Disabled 2.0 mA
Enabled (no load) 2.5
Input Voltage Slew Rate VIN_SR 1 V / μs
Output Specifications
Output Voltage Total Regulation VOUT_DC [2] 3.25 3.30 3.36 V
Output Voltage Trim Range VOUT_DC [3] [7] 2.3 3.3 4.1 V
Line Regulation VOUT (VIN) @25°C, 8V < VIN < 36V 0.10 %
Load Regulation VOUT (IOUT) @25°C, 0.5A < IOUT < 15A 0.10 %
Output Voltage Ripple VOUT_AC IOUT = 5A, COUT = 4 x 100μF, 20MHz BW [4] 37.5 mVp-p
Continuous Output
Current Range IOUT_DC [5] [7] 015 A
Current Limit IOUT_CL 18.0 A
Protection
VIN UVLO Start Threshold VUVLO_START 7.10 7.60 8.00 V
VIN UVLO Stop Threshold VUVLO_STOP 6.80 7.25 7.60 V
VIN UVLO Hysteresis VUVLO_HYS 0.35 V
VIN OVLO Start Threshold VOVLO_START 36.1 37.6 V
VIN OVLO Stop Threshold VOVLO_STOP 37.0 38.4 V
VIN OVLO Hysteresis VOVLO_HYS 0.8 V
VIN UVLO/OVLO Fault Delay Time tf_DLY Number of the switching frequency cycles 128 Cycles
VIN UVLO/OVLO Response Time tf500 ns
Output Overvoltage Protection VOVP Above VOUT 20 %
Overtemperature
Fault Threshold TOTP [2] 130 135 140 °C
Overtemperature
Restart Hysteresis TOTP_HYS 30 °C
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
[7] Minimum 5V between VIN–VOUT must be maintained or a minimum load of 1mA required.
VICOR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 16 of 27 11/2016
PI33xx-x1
PI3301-x1-LGIZ (3.3VOUT) Electrical Characteristics (Cont.)
Unless otherwise specified: -40°C < TJ < 125°C, VIN = 24V, L1 = 155nH [1]
Parameter Symbol Conditions Min Typ Max Unit
Timing
Switching Frequency fS[6] 650 kHz
Fault Restart Delay tFR_DLY 30 ms
Sync In (SYNCI)
Synchronization Frequency
Range fSYNCI Relative to set switching frequency [3] 50 110 %
SYNCI Threshold VSYNCI 2.5 V
Sync Out (SYNCO)
SYNCO High VSYNCO_HI Source 1mA 4.5 V
SYNCO Low VSYNCO_LO Sink 1mA 0.5 V
SYNCO Rise Time tSYNCO_RT 20pF load 10 ns
SYNCO Fall Time tSYNCO_FT 20pF load 10 ns
Soft-Start And Tracking
TRK Active Input Range VTRK Internal reference tracking range 0 1.04 V
TRK Max Output Voltage VTRK_MAX 1.2 V
TRK Disable Threshold VTRK_OV 20 40 60 mV
Charge Current (Soft-Start) ITRK -70 -50 -30 μA
Discharge Current (Fault) ITRK_DIS 6.8 mA
Soft-Start Time tSS CTRK = 0μF 2.2 ms
Enable
High Threshold VEN_HI 0.9 1 1.1 V
Low Threshold VEN_LO 0.7 0.8 0.9 V
Threshold Hysteresis VEN_HYS 100 200 300 mV
Enable Pull-Up Voltage
(floating, unfaulted) VEN_PU 2 V
Enable Pull-Down Voltage
(floating, faulted) VEN_PD 0 V
Source Current IEN_SO -50 μA
Sink Current IEN_SK 50 μA
[1] All parameters reflect regulator and inductor system performance. Measurements were made using a standard PI33xx evaluation board with 3x4”
dimensions and 4 layer, 2oz copper. Refer to inductor pairing table within Application Description section for specific inductor manufacturer and value.
[2] Regulator is assured to meet performance specifications by design, test correlation, characterization, and/or statistical process control.
[3] Output current capability may be limited and other performance may vary from electrical characteristics when switching frequency or VOUT is modified.
[4] Refer to Output Ripple plots.
[5] Refer to Load Current vs. Ambient Temperature curves.
[6] Refer to Switching Frequency vs. Load current curves.
[7] Minimum 5V between VIN–VOUT must be maintained or a minimum load of 1mA required.
CH4 . CH1 vom- zoumwdiv ‘I'Imehase mugs/aw CH4 low' 5A1d|v CH1 CH1 vom- 1V/div CH4|.N'1A/dlv Tlmebase SODps/dlv CH1 vom- 50mV/div Tlrnebase 2ps/dlv CH! CH1 Vour' 50mV/div Tlmebase Zusldlv VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 17 of 27 11/2016
PI33xx-x1
Figure 20 — Short Circuit Test
Figure 19 — Efficiency at 25°C
Figure 21 — Switching Frequency vs. Load Current
Figure 22 — Transient Response 7.5A to 15A, at 5A/µs
24VIN to 3.3VOUT, COUT = 8 x 100µF Ceramic
Figure 24 — Output Ripple 24VIN, 3.3VOUT at 7.5A
COUT = 8 x 100µF Ceramic
Figure 23 — Output Ripple 24VIN, 3.3VOUT at 15A
COUT = 8 x 100µF Ceramic
PI3301-x0-LGIZ (3.3VOUT) Electrical Characteristics (Cont.)
Load Current (A)
Frequency (kHz)
VIN = 12VVIN = 8V
21
0
100
200
300
400
500
600
700
800
3456789101213141511
VIN = 24VV
IN = 36V
Load Current (A)
Efficiency (%)
VIN = 12VVIN = 8V
50
55
65
75
85
95
60
70
80
90
100
012345678910 11 12 13 14 15
VIN = 24VV
IN = 36V
> f’fl Ml “Hi VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 18 of 27 11/2016
PI33xx-x1
Functional Description
The PI33xx-x1 is a family of highly integrated ZVS-Buck regulators.
The PI33xx-x1 has a set output voltage that is trimmable within a
prescribed range shown in Table 2. Performance and maximum
output current are characterized with a specific external power
inductor (see Table 5).
For basic operation, Figure 25 shows the connections and
components required. No additional design or settings
are required.
ENABLE (EN)
EN is the enable pin of the converter. The EN Pin is referenced
to SGND and permits the user to turn the regulator on or off.
The EN default polarity is a positive logic assertion. If the EN pin
is left floating or asserted high, the converter output is enabled.
Pulling EN pin below 0.8VDC with respect to SGND will disable the
regulator output.
The EN input polarity can be programmed (PI33xx-21 device
versions only) via the I2C data bus. When the EN pin polarity is
programmed for negative logic assertion; and if the EN pin is left
floating, the regulator output is enabled. Pulling the EN pin above
1.0VDC with respect to SGND will disable the regulator output.
Remote Sensing
An internal 100Ω resistor is connected between REM pin and
VOUT pin to provide regulation when the REM connection is
broken. Referring to Figure 25, it is important to note that L1 and
COUT are the output filter and the local sense point for the power
supply output. As such, the REM pin should be connected at COUT
as the default local sense connection unless remote sensing to
compensate additional distribution losses in the system. The REM
pin should not be left floating.
Switching Frequency Synchronization
The SYNCI input allows the user to synchronize the controller
switching frequency by an external clock referenced to SGND.
The external clock can synchronize the unit between 50% and
110% of the preset switching frequency (fS). For PI33xx-21 device
versions only, the phase delay can be programmed via I2C bus
with respect to the clock applied at SYNCI pin. Phase delay
allows PI33xx-21 regulators to be paralleled and operate in an
interleaving mode.
The PI33xx-x1 default for SYNCI is to sync with respect to the
falling edge of the applied clock providing 180° phase shift from
SYNCO. This allows for the paralleling of two PI33xx-x1 devices
without the need for further user programming or external sync
clock circuitry. The user can change the SYNCI polarity to sync
with the external clock rising edge via the I2C data bus (PI33xx-21
device versions only).
When using the internal oscillator, the SYNCO pin provides a
5V clock that can be used to sync other regulators. Therefore,
one PI33xx-x1 can act as the lead regulator and have additional
PI33xx-x1s running in parallel and interleaved.
Soft-Start
The PI33xx-x1 includes an internal soft-start capacitor to ramp the
output voltage in 2ms from 0V to full output voltage. Connecting
an external capacitor from the TRK pin to SGND will increase the
start-up ramp period. See “Soft Start Adjustment and Track,” in
the Applications Description section for more details.
Output Voltage Trim
The PI33xx-x1 output voltage can be trimmed up from the preset
output by connecting a resistor from ADJ pin to SGND and can
be trimmed down by connecting a resistor from ADJ pin to VOUT.
Table 2 defines the voltage ranges for the PI33xx-x1 family.
EN
SGND
V
IN
VIN
VOUT
SYNCI
VS1
V
OUT
PGND
SYNCO
REM
TRK
ADJ
EAO
PI33xx
C
IN
C
OUT
L1
Table 2 — PI33xx-x1 family output voltage range
Figure 25 — ZVS-Buck with required components
Device Output Voltage
Set Range
PI3311-x1-LGIZ 1.0V 1.0 to 1.4V
PI3318-x1-LGIZ 1.8V 1.4 to 2.0V
PI3312-x1-LGIZ 2.5V 2.0 to 3.1V
PI3301-x1-LGIZ 3.3V 2.3 to 4.1V
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 19 of 27 11/2016
PI33xx-x1
Output Current Limit Protection
PI33xx-x1 has two methods implemented to protect from output
short or over current condition.
Slow Current Limit protection: prevents the output load from
sourcing current higher than the regulator’s maximum rated
current. If the output current exceeds the Current Limit (IOUT_CL)
for 102s, a slow current limit fault is initiated and the regulator
is shut down which eliminates output current flow. After Fault
Restart Delay (tF R _DLY ), a soft-start cycle is initiated. This restart
cycle will be repeated indefinitely until the excessive load
is removed.
Fast Current Limit protection: PI33xx-x1 monitors the regulator
inductor current pulse-by-pulse to prevent the output from
supplying very high current due to sudden low impedance short.
If the regulator senses a high inductor current pulse, it will initiate
a fault and stop switching until Fault Restart Delay ends and then
initiate a soft-start cycle.
Both the Fast and Slow current limit faults are stored in a Fault
Register and can be read and cleared (PI33xx-21 device versions
only) via I2C data bus.
Input Undervoltage Lockout
If VIN falls below the input Undervoltage Lockout (UVLO)
threshold, the regulator will enter a low power state and
initiate a fault. The system will restart once the input voltage is
reestablished and after the Fault Restart Delay. A UVLO fault is
stored in a Fault Register and can be read and cleared (PI33xx-21
device versions only) via I2C data bus.
Input Overvoltage Lockout
If VIN exceeds the input Overvoltage Lockout (OVLO) threshold
(VOVLO), while the regulator is running, the PI33xx-x1 will complete
the current cycle and stop switching. The system will resume
operation after the Fault Restart Delay. The OVLO fault is stored
in a Fault Register and can be read and cleared (PI33xx-21 device
versions only) via I2C data bus.
Output Overvoltage Protection
The PI33xx-x1 family is equipped with output Overvoltage
Protection (OVP) to prevent damage to input voltage sensitive
devices. If the output voltage exceeds 20% of its set regulated
value, the regulator will complete the current cycle, stop switching
and issue an OVP fault. The system will resume operation once
the output voltage falls below the OVP threshold and after Fault
Restart Delay. The OVP fault is stored in a Fault Register and can
be read and cleared (PI33xx-21 device versions only) via I2C data
bus.
Overtemperature Protection
The internal package temperature is monitored to prevent internal
components from reaching their thermal maximum. If the Over
Temperature Protection Threshold (OTP) is exceeded (TOTP), the
regulator will complete the current switching cycle, enter a low
power mode, set a fault flag, and will soft-start when the internal
temperature falls below Overtemperature Restart Hysteresis
(TOTP_HYS). The OTP fault is stored in a Fault Register and can be
read and cleared (PI33xx-21 device versions only) via I2C data bus.
Pulse Skip Mode (PSM)
PI33xx-x1 features a PSM to achieve high efficiency at light loads.
The regulators are setup to skip pulses if EAO falls below a PSM
threshold. Depending on conditions and component values, this
may result in single pulses or several consecutive pulses followed
by skipped pulses. Skipping cycles significantly reduces gate drive
power and improves light load efficiency. The regulator will leave
PSM once the EAO rises above the Skip Mode threshold.
Variable Frequency Operation
Each PI33xx-x1 is preprogrammed to a base operating frequency,
with respect to the power stage inductor (see Table 5), to
operate at peak efficiency across line and load variations. At
low line and high load applications, the base frequency will
decrease to accommodate these extreme operating ranges.
By stretching the frequency, the ZVS operation is preserved
throughout the total input line voltage range therefore
maintaining optimum efficiency.
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Cool-Power® ZVS Switching Regulators Rev 1.4
Page 20 of 27 11/2016
PI33xx-x1
Parallel Operation
Paralleling modules can be used to increase the output current
capability of a single power rail and reduce output voltage ripple.
By connecting the EAO pins and SGND pins of each module
together the units will share the current equally. When the TRK
pins of each unit are connected together, the units will track each
other during soft-start and all unit EN pins have to be released to
allow the units to start (See Figure 26). Also, any fault event in any
regulator will disable the other regulators. The two regulators will
be out of phase with each other reducing output ripple (refer to
Switching Frequency Synchronization).
To provide synchronization between regulators over the entire
operational frequency range, the Parallel Good (PGD) pin must be
connected to the lead regulator’s (#1) SYNCI pin and a
2.5kΩ Resistor, R1, must be placed between SYNCO (#2) return
and the lead regulator’s SYNCI (#1) pin, as shown in Figure 26. In
this configuration, at system soft-start, the PGD pin pulls SYNCI
low forcing the lead regulator to initialize the open-loop startup
synchronization. Once the regulators reach regulation, SYNCI is
released and the system is now synchronized in a closed-loop
configuration which allows the system to adjust, on the fly, when
any of the individual regulators begin to enter variable frequency
mode in the loop.
Multi-phasing three regulators is possible (PI33xx-21 only)
with no change to the basic single-phase design. For more
information about how to program phase delays within the
regulator, please refer to Picor application note
PI33xx-2x Multi-Phase Design Guide.
I2C Interface Operation
PI33xx-21 devices provide an I2C digital interface that enables the
user to program the EN pin polarity (from high to low assertion)
and switching frequency synchronization phase/delay. These are
one time programmable options to the device.
Also, the PI33xx-21 devices allow for dynamic VOUT margining via
I2C that is useful during development (settings stored in volatile
memory only and not retained by the device). The PI33xx-21 also
have the option for fault telemetry including:
Overtemperature protection
Fast / Slow current limit
Output voltage high
Input overvoltage
Input undervoltage
For more information about how to utilize the I2C interface
please refer to Picor application note PI33xx-2x I2C Digital
Interface Guide.
SGND
VS1
PGND
REM
TRK
EAO
(#1)
SGND
VS1
PGND
REM
(#2)
EN
EAO (#2)
TRK(#2)
EN (#2)
PGD
SYNCI
SYNCO
SYNCI (#2)
SYNCO(#2)
R1
TRK
EAO
EN
EAO (#1)
TRK(#1)
EN (#1)
PGD
SYNCI
SYNCO
SYNCI (#1)
SYNCO (#1)
V
IN
VIN
VOUT
V
OUT
C
IN
C
OUT
L1
L1
V
IN
VIN
VOUT
C
IN
C
OUT
PI33xx
PI33xx
Figure 26 — PI33xx-x1 parallel operation
R1 R1( ) R1 VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 21 of 27 11/2016
PI33xx-x1
Application Description
Output Voltage Trim
The PI33xx-x1 family of Buck Regulators provides seven common
output voltages: 1.0V, 1.8V, 2.5V, and 3.3V. A post-package
trim step is implemented to offset any resistor divider network
errors ensuring maximum output accuracy. With a single resistor
connected from the ADJ pin to SGND or REM, each device’s
output can be varied above or below the nominal set voltage
(with the exception of the PI3311-X1 which can only be above the
set voltage of 1V).
The remote pin (REM) should always be connected to the VOUT
pin, if not used, to prevent an output voltage offset. Figure 27
shows the internal feedback voltage divider network.
R1, R2, and R4 are all internal 1.0% resistors and Rlow and Rhigh
are external resistors for which the designer can add to modify
VOUT to a desired output. The internal resistor value for each
regulator is listed below in Table 4.
By choosing an output voltage value within the ranges stated in
Table 3, VOUT can simply be adjusted up or down by selecting the
proper Rhigh or Rlow value, respectively. The following equations
can be used to calculate Rhigh and Rlow values:
If, for example, a 4.0V output is needed, the user should choose
the regulator with a trim range covering 4.0V from Table 3. For
this example, the PI3301 is selected (3.3V set voltage). First step
would be to use Equation (1) to calculate Rhigh since the required
output voltage is higher than the regulator set voltage. The
resistor-divider network values for the PI3301 are can be found
in Table 4 and are R1 = 2.61kΩ and R2 = 1.13kΩ. Inserting these
values in to Equation (1), Rhigh is calculated as follows:
Resistor Rhigh should be connected as shown in Figure 27 to
achieve the desired 4.0V regulator output. No external Rlow
resistor is need in this design example since the trim is above the
regulator set voltage.
The PI3311-x1 output voltage can only be trimmed higher than
the factory 1V setting. The following Equation (4) can be used
calculate Rhigh values for the PI3311-x1 regulators.
Device Output Voltage
Set Range
PI3311-x1-LGIZ 1.0V 1.0 to 1.4V
PI3318-x1-LGIZ 1.8V 1.4 to 2.0V
PI3312-x1-LGIZ 2.5V 2.0 to 3.1V
PI3301-x1-LGIZ 3.3V 2.3 to 4.1V
+
-ADJ
REM
V
OUT
R2
R1
R4
SGND
R
low
R
high
1.0V
DC
Figure 27 — Internal resistor divider network
Table 3 — PI33xx-x1 family output voltage range
Table 4 — PI33xx-x1 Internal divider values
Device R1 R2 R4
PI3311-x1-LGIZ 1k Open 100
PI3318-x1-LGIZ 0.806k 1.0k 100
PI3312-x1-LGIZ 1.5k 1.0k 100
PI3301-x1-LGIZ 2.61k 1.13k 100
1
Rhigh
R1
(
)
VOUT 11
R2
=
(
)
(1)
1
Rlow
R1
(
)
VOUT 1
1
R1
=
(
)
1(2)
1
3.78k
(
)
4.0 1 1
1.13k
=
(
)
2.61k
(3)
1
R
high (1V)
R1
(
)
VOUT 1
= (4)
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 22 of 27 11/2016
PI33xx-x1
Soft-Start Adjust and Tracking
The TRK pin offers a means to increase the regulator’s soft-start
time or to track with additional regulators. The soft-start slope is
controlled by an internal capacitor and a fixed charge current to
provide a Soft-Start Time tSS for all PI33xx-x1 regulators. By adding
an additional external capacitor to the TRK pin, the soft-start time
can be increased further. The following equation can be used to
calculate the proper capacitor for a desired soft-start times:
Where, tTRK is the soft-start time and ITRK is a 50μA internal
charge current (see Electrical Characteristics for limits).
There is typically either proportional or direct tracking
implemented within a design. For proportional tracking
between several regulators at startup, simply connect all
devices’ TRK pins together. This type of tracking will force all
connected regulators to startup and reach regulation at the
same time (see Figure 28(a)).
For Direct Tracking, choose the regulator with the highest output
voltage as the master and connect the master to the TRK pin of
the other regulators through a divider (Figure 29) with the same
ratio as the slave’s feedback divider (see Table 4 for values).
All connected regulators’ soft-start slopes will track with this
method. Direct tracking timing is demonstrated in Figure 28(b). All
tracking regulators should have their Enable (EN) pins connected
together to work properly.
Inductor Pairing
The PI33xx-x1 utilizes an external inductor. This inductor has been
optimized for maximum efficiency performance. Table 5 details
the specific inductor value and part number utilized for each
PI33xx-x1 device which are manufactured by Eaton. Data sheets
are available at:
http://www.cooperindustries.com
VOUT 1
VOUT 2
Master VOUT
VOUT 2
(a)
(b)
t
Figure 28 — PI33xx-x1 tracking methods
Master V
OUT
R1
R2
SGND
TRK
PI33xx
Slave
Figure 29 — Voltage divider connections for direct tracking
Table 5 — PI33xx-x1 Inductor pairing
Device Inductor
[nH]
Inductor
Part Number Manufacturer
PI3311-x1 85 FPV1006-85-R Eaton
PI3318-x1 125 FPV1006-125-R Eaton
PI3312-x1 125 FPV1006-125-R Eaton
PI3301-x1 150 FPV1006-150-R Eaton
CTRK = (5)tTRK • ITRK 100 • 10 -9
()
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 23 of 27 11/2016
PI33xx-x1
Layout Guidelines
To optimize maximum efficiency and low noise performance from
a PI33xx-x1 design, layout considerations are necessary. Reducing
trace resistance and minimizing high current loop returns along
with proper component placement will contribute to
optimized performance.
A typical buck converter circuit is shown in Figure 30. The
potential areas of high parasitic inductance and resistance are the
circuit return paths, shown as LR below.
The path between the COUT and CIN capacitors is of particular
importance since the AC currents are flowing through both of
them when Q1 is turned on.
Figure 31, schematically, shows the reduced trace length
between input and output capacitors. The shorter path lessens
the effects that copper trace parasitics can have on the
PI33xx-x1 performance.
When Q1 is on and Q2 is off, the majority of CINs current is used
to satisfy the output load and to recharge the COUT capacitors.
When Q1 is off and Q2 is on, the load current is supplied by the
inductor and the COUT capacitor as shown in Figure 32. During this
period CIN is also being recharged by the VIN. Minimizing CIN loop
inductance is important to reduce peak voltage excursions when
Q1 turns off. Also, the difference in area between the CIN loop
and COUT loop is vital to minimize switching and GND noise.
The recommended component placement, shown in Figure 33,
illustrates the tight path between CIN and COUT (and VIN and VOUT)
for the high AC return current. This optimized layout is used on
the PI33xx-x1 evaluation board.
COUT
CIN
VIN
Figure 30 — Typical Buck Converter
COUT
VIN CIN
Q2
Q1
IND
Figure 31 — Current flow: Q1 closed
COUT
VIN CIN
Figure 32 — Current flow: Q2 closed
COUT
CIN
VIN
VOUT
GND
GND
VSW
Figure 33 — Recommended component placement and
metal routing
‘ Outline of 10mm x 14mm SIP package. / All pads are an 1mm square grid. 0.55mm f I155mm (GDP) Detail A - Recommended snide/mask openings. CDP = Copper defined pads. VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 24 of 27 11/2016
PI33xx-x1
Figure 34 — Recommended Receiving PCB footprint
Recommended PCB Footprint and Stencil
Figure 34 details the recommended receiving footprint for PI33xx-x1 10mm x 14mm package. All pads should have a final copper size of
0.55mm x 0.55mm, whether they are solder-mask defined or copper defined, on a 1mm x 1mm grid. All stencil openings are 0.45mm when
using a 6mil stencil.
\Iwb SI FIN 1 INDEX mp vIEw man A \V ‘ \ Pm 1 INDEX ’ SIDE VIEW Em « DE DE LILJLILHJLILI LILILILI LILIILILI DD‘EID uuu‘uu DDDD‘EID DDDDDD DDDDDD DECK DUDE EDD EDD DEBAJ BOTTOM vIEw ng EXPOSED FAD " DETAIL A METAL/ZED FAD EW’USED ”AD , (4) DETAIL B Nair: . M®©®® 'e' REPRESENTS THE BASIC TERMINAL PITCH. SPECIFIES THE TIIUE EEOMEIIIIC PDSITIDN OF THE TERMINAL AXIS. DIMENSION 'b'APPLIES m METALLIZEI) TERMINAL AND Is MEASURED BE1WE£N Lqumm ANDII.25mm FROM I'EIIMINAL w. DIMENSION 'A' INCLUDES PACKAGE WAKPAEE. EXPDSED METALLIZED PADSAIIE CU PADS WITH SURFACE FINISH FRCITELTIDN. ALL DIMENSIONS ARE IN MILLIMETEAs. VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 25 of 27 11/2016
PI33xx-x1
LGIZ Package Drawing
DIMESIONAL REFERENCES
NOMMINREF. MAX
A
A1
A2
b
L
D1
D
E
E1
e
L1
aaa
bbb
ccc
ddd
eee 0.08
2.562.50 2.62
0.05
2.57
14.00 BSC
0.550.50 0.60
10.00 BSC
13.00 BSC
9.00 BSC
1.00 BSC
0.150.10 0.20
0.10
0.10
0.08
0.10
0.550.50 0.60
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 26 of 27 11/2016
PI33xx-x1
Revision History
Revision Date Description Page Number(s)
1.3 09/15/16 Last release in old format n/a
1.4 11/21/16
Reformatted in new template
Clarified VS1 rating in Absolute Maximum Ratings Table
Updated pin description table and package pin-out labels
to show VDR capability
all
4
5
VICDR
Cool-Power® ZVS Switching Regulators Rev 1.4
Page 27 of 27 11/2016
PI33xx-x1
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