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SN74ABT125Q-Q1: SN74ABT125Q-Q1 output-pull up

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Part Number: SN74ABT125Q-Q1

In of our applications we are using the device SN74ABT125 for HFBR-1414Z LED sink operation.


1) The O/P Pin of the device is connected to the Cathode of HFBR-1414Z to the sink the LED current (60mA). In this scenario the O/P pin of the device SN74ABT125 sees a continuous voltage of 3V when LED is not sinking current( HFBR-1414Z LED Anode voltage- LED Drop).Please suggest if we can use this configuration.


2) Can the O/P pins of the device SN74ABT125  tied together for current sharing during the sink operation.

3)Can   Push Pull output pin  be pulled high, so that it will see a voltage on its o/p pin.

  • Hello and Welcome to the forums!

    Please see my responses to your questions below.

    1) If I understand correctly, you need to be able to sink 60 mA from the external device, and when it is not sinking current you want to know if the output is tolerant to 3V. (I think you may have tried to attach an image, but I am not sure).
    If you want the output only to ever sink current, and never source current, then it would be recommended to connect the input of the channel to GND so that when the device is enabled, the output is pulling low. If you leave the input connected low, and simply toggle the OE pin to switch between high impedance and pulling low, then this would be perfectly acceptable for this device.

    2) Yes, you can parallel outputs to share current between channels and get additional sink current capability or a lower VOL voltage.

    3) If you want to source current from the output then you can pull the input high so that the output is high, however if there is always a 3V potential on the output then this would not be recommended, as there will be bus contention and could cause a large current output larger than what the device can manage unless this current is limited to within the ratings of the device.

    Hopefully I answered all of your questions, but please feel free to let me know if anything is not clear or you have additional questions.
    We constantly have product experts monitoring these forums, so please continue to post and we are very happy to help!

    Best,
    Michael

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