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TCA9535: TCA9535

dai_sakamoto
Intellectual 330 points
Part Number: TCA9535

Tool/software:

In the TCA9535, do the SCL and SDA pins have a high-side clamp diode protection? 　"SCL → Diode → VCC" 　

Also, please tell me the absolute maximum rated voltage of the SCL and SDA pins.

I was curious because the data sheet states: "(1) For voltages applied above VCC, an increase in ICC results."

  • 0
    TI__Mastermind 47448 points

    Hi Dai,

    I measured on similar IP. No SDA/SCL diode to VCC present. 

     The abs. max conditions for SDA/SCL are listed in the following table: 

    Where VI <= 6 V for SDA/SCL. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    Intellectual 330 points

    Thank you.

    In this case, Vcc<=Vi.

    Is there a way to calculate how much Icc will increase?

    I'm worried about the IC overheating, etc.

    Vcc is connected to 5V with a load switch.

    Vcc=5.0V - Ron x Icc =4.993V

    Vi(SCL)=5.0V

    Icc = 20mA (maximum value in application)

    Ron＝0.3Ω

  • 0 in reply to dai_sakamoto
    TI__Mastermind 47448 points

    Hi Dai,

    There is not a calculation in the datasheet that can be used to determine excess ICC when VI goes above VCC of the device. 

    For Ron = 0.3 ohm, this is very small resistance. Could also be the difference of a small jumper wire connecting to the TCA9535. I doubt this would increase the current that much as to damage the chip. 

    Is it possible to connect CPU VCC and 10k PU resistor to the node right after the switch? 

    Regards,

    Tyler