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TCA9535: TCA9535 - Default state of IO ports at poweron

vijayavani raju
Prodigy 220 points
Part Number: TCA9535

Hi Team,

Its stated in datasheet that at power on all IO all IO act as inputs.

If I use IO expander's IO as output to sink a LED driven from supply. In such case to prevent LED being lit at poweron, should I need a pullup resistor at the IO PIN.

Please clarify

  • 0
    TI__Guru 62920 points

    Hello,

    I wouldn't expect you to need a pullup resistance. When a port is configured as an input it will be high-Z and source/sink minimal currents. As such, the LEDs should not illuminate. That said, a pullup resistance may be useful in reducing the current consumption of the device at startup since current consumption is lowest when inputs are fully biased to either VCC or GND.

    Max