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LM2903-Q1: Connecting resistors to input pins in unused channel

Shunsuke Yamamoto
Expert 8521 points
Part Number: LM2903-Q1


Hi team,

My customer plans to use only one channel in LM2903-Q1. In this case, should the input pins of unused channels be connected to resistors or GND directly? Based on the application note, Connecting resistors are recommended.

Best regards,

Shunsuke Yamamoto

  • +1
    TI__Guru 62826 points

    Hello Shunsuk-san,

    For the grounded side, if you can connect the input directly to the GND pin, with copper on the same layer (no vias), then you really do not need the resistor.

    We always recommend  resistors any time connecting directly to VCC

  • 0 in reply to Paul Grohe
    TI__Expert 8521 points

    Hi Paul, 

    Sorry for asking a question after press "solved" button.

    When connecting GND directly to input pins of op amps and GND become positive, the overcurrent condition on Input pins occurs and IC becomes broken. Only 1 channel becomes broken? or 2 channels of IC become broken?

    Best regards,

    Shunsuke Yamamoto

  • 0 in reply to Shunsuke Yamamoto
    TI__Genius 12025 points

    Hi Shunsuke-san,

    Since both channels are on the same die, exceeding the absolute maximum input current on one channel has the potential to destroy the entire device (both channel 1 and channel 2) due to electrical overstress. It's a possibility that only one channel gets destroyed and the other channel remains functional, but it is not a reliable and consistent result.