Interface μModule Transceivers

Linear Technology’s Isolator µModule® Technology is a new development platform that allows Linear to reliably integrate inductive/magnetic isolation, discrete components, ICs and power onto a single substrate PCB. This high level of integration results in products that require no external components. All resistors, capacitors, inductors and ICs are onboard.

Any application from signaling to sampling can be supported by the platform, delivering isolation to even non-traditional applications. High power levels (up to 1 W), supported by low ripple regulation, a cored power transformer that reduces radiated emissions, and better-than-average efficiency up to 65%, are available to the application. Not only is the device self-powered, but it also provides external isolated power for other neighboring functions. To achieve greater than 2500VRMS isolation, the technology uses coupled signal inductors embedded in our µModule substrate. This technique ensures consistent ruggedness and reliability. This platform will be certified by safety houses, including UL, CSA and IEC to guarantee the isolation barrier’s effectiveness.


  • LTM2881
  • LTM2882

LTM2881 - Complete Isolated RS485/RS422 μModule Transceiver + Power

The LTM2881 is a complete galvanically isolated full-duplex RS485/RS422 μModule transceiver. No external components are required. A single supply powers both sides of the interface through an integrated, isolated, low noise, efficient 5V output DC/DC converter.

Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems where the ground loop is broken allowing for large common mode voltage variation. Uninterrupted communication is guaranteed for common mode transients greater than 30kV/μs.

Maximum data rates are 20Mbps or 250kbps in slew limited mode. Transmit data, DI and receive data, RO, are implemented with event driven low jitter processing. The receiver has a one-eighth unit load supporting up to 256 nodes per bus. A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply.

Enhanced ESD protection allows this part to withstand up to ±15kV (human body model) on the transceiver interface pins to isolated supplies and ±10kV through the isolation barrier to logic supplies without latch-up or damage.

Features

  • Isolator μModule Technology
  • Isolated RS485/RS422 Transceiver: 2500VRMS
  • Integrated Isolated DC/DC Converter: 1W, 62% Efficiency
  • No External Components Required
  • 20Mbps or Low EMI 250kbps Data Rate
  • High ESD: ±15kV HBM on Transceiver Interface
  • High Common Mode Transient Immunity: 30kV/μs
  • Integrated Selectable 120Ω Termination
  • 3.3V (LTM2881-3) or 5.0V (LTM2881-5) Operation
  • 1.62V to 5.5V Logic Supply Pin for Flexible Digital Interface
  • Common Mode Working Voltage: 560VPEAK
  • High Input Impedance Failsafe RS485 Receiver
  • Current Limited Drivers and Thermal Shutdown
  • Compatible with TIA/EIA-485-A Specification
  • High Impedance Output During Internal Fault Condition
  • Low Current Shutdown Mode (< 10μA)
  • General Purpose CMOS Isolated Channel
  • Small, Low Profile (15mm × 11.25mm × 2.8mm) Surface Mount LGA Package
Digi-Key Part Number Linear Technology P/N Description
LTM2881CV-3#PBF-ND LTM2881CV-3#PBF IC TXRX RS485/RS422 32-LGA
LTM2881IY-5#PBF-ND LTM2881IY-5#PBF IC TXRX RS485/RS422 32BGA
LTM2881IY-3#PBF-ND LTM2881IY-3#PBF IC TXRX RS485/RS422 32BGA

LTM2882 - Dual Isolated RS232 μModule Transceiver + Power

The LTM2882 is a complete galvanically isolated dual RS232 μModule transceiver. No external components are required. A single 3.3V or 5V supply powers both sides of the interface through an integrated, isolated DC/DC converter. A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply.

Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems with different grounds, allowing for large common mode voltages. Uninterrupted communication is guaranteed for common mode transients greater than 30kV/μs.

This part is compatible with the TIA/EIA-232-F standard. Driver outputs are protected from overload and can be shorted to ground or up to ±15V without damage. An auxiliary isolated digital channel is available. This channel allows configuration for half-duplex operation by controlling the DE pin.

Enhanced ESD protection allows this part to withstand up to ±10kV (human body model) on the transceiver interface pins to isolated supplies and across the isolation barrier to logic supplies without latchup or damage.

Features

  • Isolator μModule Technology
  • Isolated Dual RS232 Transceiver: 2500VRMS
  • Integrated Isolated DC/DC Converter:
    1W, 65% Efficiency
  • No External Components Required
  • 1.62V to 5.5V Logic Supply for Flexible Digital Interface
  • High Speed Operation
    1Mbps for 250pF/3kΩ Load
    250kbps for 1nF/3kΩ Load
    100kbps for 2.5nF/3kΩ TIA/EIA-232-F Load
  • 3.3V (LTM2882-3) or 5V (LTM2882-5) Operation
  • No Damage or Latchup to ±10kV ESD HBM on Isolated RS232 Interface or Across Isolation Barrier
  • High Common Mode Transient Immunity: 30kV/μs
  • Common Mode Working Voltage: 560VPEAK
  • True RS232 Compliant Output Levels
  • Small Low Profile (15mm × 11.25mm × 2.8mm) Surface Mount LGA Package
Click here for datasheet

Typical Application

Digi-Key Part Number Manufacturer Part Number Description
LTM2882CV-5#PBF-ND LTM2882CV-5#PBF IC TXRX RS232 32LGA
LTM2882CV-3#PBF-ND LTM2882CV-3#PBF IC TXRX RS232 32LGA
LTM2882IV-5#PBF-ND LTM2882IV-5#PBF IC TXRX RS232 32LGA
LTM2882IV-3#PBF-ND LTM2882IV-3#PBF IC TXRX RS232 32LGA
LTM2882CY-5#PBF-ND LTM2882CY-5#PBF IC TXRX DUAL RS232 32BGA
LTM2882IY-5#PBF-ND LTM2882IY-5#PBF IC TXRX DUAL RS232 32BGA
LTM2882IY-3#PBF-ND LTM2882IY-3#PBF IC TXRX DUAL RS232 32BGA