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TCA9517: I2Cb pulled up to always on 3V3 issue

Gary Jiang
Intellectual 980 points
Part Number: TCA9517

Hi team,

My customer wants to ask the following question, as I2C pulled up supply is a always-on 3.3V supply(VDD3V3), and the VCCB and EN is a powered by a normal 3.3V supply(IO3V3_1) which will be pulled down during sleep mode of the system:

1. When the TCA9517 is powered on, the SCLB and SDAB will be pulled up by always-on supply before the VCCB and EN are pulled up. They want to know if this sequence will influence the operation of the chip;

I don't think this power up sequence will affect the operation of TCA9517, as it's OD I2C I/O, but I'm not 100% sure, so I want to ask you guys about it.

Thank you.

Gary

  • 0
    TI__Guru 72501 points

    Hey Taoran,

    The TCA9517 should be high impedance if VccA and VccB are not both powered up. The same can be said if you have the enable held low. Powering up either supply or while the I2C buses are held high should not affect the device.

    Thanks,

    -Bobby