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Original question:

TDA4VM: I2C address for GPIO expander 2

TCA6424A: I2C Bus address setting

Alan Chang
Intellectual 2260 points
Part Number: TCA6424A

Hi,

    I have a question about TCA6424A address setting. If VCCP is 1.8V, can we use 3.3V at ADDR pin? From data sheet, "H" level requests 0.7Vccp ~ 5.5V.

Is it OK to set "H" in address? It's a 2nd source replacement question.

  

  • 0
    TI__Guru 63140 points

    Hey Alan,

    I looked under the hood at the address pin for this device and found an ESD cell in series with a CMOS gate. The ESD cell should have no problems with this as long as you don't drive the input of the address pin below GND or above ~7V. The CMOS gate should be okay with this as well as long as you don't violate the absolute maximum conditions.

    -Bobby

  • 0 in reply to BOBBY
    TI__Intellectual 2260 points

    Hi Bobby,

       Another question is ADDR pin pull-high timing. Any timing request? example:

    1. if 3.3V is 1st coming, then VCCP is ready?

    2. if VCCP is ready, then 3.3V is available. 

      When does device detect ADDR pin voltage level and decide address?

  • 0 in reply to Alan Chang
    TI__Guru 63140 points

    "  When does device detect ADDR pin voltage level and decide address?"

    The address pin does not latch upon start up. It can change after power up.

    -Bobby