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TCA9555: Recommended value of Input supply current

Kiranjit Kaur
Intellectual 395 points
Part Number: TCA9555
Other Parts Discussed in Thread: TM4C1292NCPDT,

Hi,

I need to know how much input supply current I can give to the IO expander IC for one channel with respect to VCC 3.3V.

In my circuit, I'm connecting I2C lines of TM4C1292NCPDT microcontroller to this IC with isolator in between.

I gave 3.3V and 500mA to the right side of my isolator which is connected to the IO expander IC, but the supply and GND got shorted.

Please guide on the recommended value of input supply current to be given to TCA9555 IC.

Best Regards,

Kiran

  • 0
    TI__Mastermind 26836 points

    Hi Kiran,

    The current consumption of TCA9555 is dependent upon the outputs. It is recommended to avoid sinking more than 10 mA from any of the device pins when they are output high. So, in theory, you could see 10 mA into VCC for each output high for the device.

    The baseline quiescent current consumption for TCA9555 is usually less than 1 mA.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Intellectual 395 points

    Hi Danny,

    Thanks for your response!!

    What is the significance of below two images:

    Should i apply 3.3 voltage with input current less than 10uA at pin Pin 24 of TCA9555?

    Thanks,

    Kiran

  • 0 in reply to Kiranjit Kaur
    TI__Mastermind 26836 points

    Kiran,

    These plots are typical characteristics plots, which show the general trend of device characteristics and their trends respective to other characteristics. In this case, these are typical characteristics plots that show the general trend of supply current as a function of temperature and supply input voltage in different states.

    Most commonly, users read these to understand the impact of temperature and voltage swings on their entire system. For example, it answers the question "What generally happens to my system when the temperature rises?" or "What happens to my system if my voltage regulator falls out of regulation?"

    These plots are simply typical characteristics, so they shouldn't be treated as maximum or minimum representations on their own. The Electrical Characteristics section of the data sheet gives any applicable bounds to these characteristics across process, voltage, and temperature (in other words, across the Recommended Operating Conditions).

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Intellectual 395 points

    Thanks , Danny for your support!!