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TCA9534A: TCA9534A application and spec clarification

Kevin Jiang1
Prodigy 60 points
Part Number: TCA9534A
Other Parts Discussed in Thread: TCA9554A

1) We expected to use IO 0-7 to control LED, which part is suggested by TI?

     TCA9534A or TCA9554A

2) Does TI suggest that I/O port connect to LED directly?

3) Check datasheet, TCA9554A embedded weak pull up (100K ohm) on I/O port. 

    It means there is a pull up resistor individually on ID0 to ID7 ? 

  • 0
    TI__Mastermind 49040 points

    Hey Kevin,

    "1) We expected to use IO 0-7 to control LED, which part is suggested by TI?"

    Devices both look the same to me, the major difference I see is that 9554 is has internal pull ups on the I/O ports.

    I would probably use the 9554 because the internal pull ups help you reference the device's input pins when the device is turned on but not initialized.

    "2) Does TI suggest that I/O port connect to LED directly?"

    I would drive the LED on by driving the I/O low. The I/O port can sink more current than it can source.

    "

    3) Check datasheet, TCA9554A embedded weak pull up (100K ohm) on I/O port. 

        It means there is a pull up resistor individually on ID0 to ID7 ?"

    Yes.

    Thanks,

    -Bobby