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SN65LBC173A: G and G/ enable question

Part Number: SN65LBC173A

I am using the line receiver to take in differential signals from an encoder and output single ended signals to a NI module. I have Vcc supplied at 5V and am using the 4 lines in and out. I have not connected anything to pins G and G/

However I don't seem to be receiving proper signals at the NI card. am I missing a connection to the G and G/ pins?

I am uncertain of the meaning of the statement below found in the datasheet.

The G and G/ inputs provide enable control logic for either positive- or negative-logic enabling all four drivers. When disabled or powered off, the receiver inputs present a high-impedance to the bus for reduced system loading.

  • Derek,

    It may make things a little clearer if you refer to the "Function Table" in the datasheet. For the Y output to properly reflect the differential input on the A and B pins, you need to either pull G high or pull /G low. Leaving them both floating would put the device in a disabled state in which the Y output is high impedance.

    Please let me know if you have any additional questions or if this doesn't fix your issue.

    Regards,
    Max