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TMUX1308: 20mA or 40mA to drive 14 decoders of TMUX1308

daniel lin
Prodigy 220 points
Part Number: TMUX1308

I plan to use 4 GPIOs of MCU to be connected to A0, A1, A2 and _EN of TMUX1308 to decide which input pin will be selected to go through output. Based on the GPIO driving strength (3.3V configurable between 20mA and 40mA), how many numbers of TMUX1308 can be driven in parallel by the GPIO?

I need to have 14 units of TMUX1308 in parallel to be connected with GPIOs of the MCU. For example, a GPIO will need to drive 14 numbers of A0 pin of TMUX1308 at the same time. Do I need to use buffer to increase GPIO's driving strength? If yes, what is the recommendation of the buffer?

  • 0
    Guru 317370 points

    The leakage current of any of the TMUX1308's logic input pins (EN, Ax) is specified as IIL/IIH. It's 1 µA in the worst case (and some nA at normal temperatures). So in theory, you can drive 20000 or 40000 muxes.

  • 0
    TI__Mastermind 35638 points

    Daniel,

    As clemens mentioned, the  IIL/IIH levels are mentioned in the datasheet with worst case being 1uA. While I wouldn't quite recommend attempting to drive 20000-40000 muxes, seeing as how your GPIO driving strength is in the mA's you should be fine with 14 multiplexers.

    Rami