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TCA9617A Power Supply Recommendations

Al B
Intellectual 2990 points
Other Parts Discussed in Thread: TCA9617A, TCA9517

For my customer...

The Power Supply Recommendations section of the TCA9617A datasheet says VCCB should always be higher than VCCA and that during power-up, VCCB must rise before VCCA. We are considering choosing this part to be an I2C repeater in our design application. We have 3.3V SCL and SDA on the VCCA side and also 3.3V SCL and SDA going to the VCCB side. So VCCA and VCCB are at the same 3.3V level. Will this be a problem? And, since both VCCA and VCCB are at the same voltage level they are also supplied by the same 3.3V source so VCCA and VCCB should come up at the same time during power-up. Will this be a problem? What would the effect be?

 

  • 0
    TI__Expert 5140 points

    Hi Al,

    To go along with this and summarize, there should be no issue with having VCCA = VCCB as this is in our datasheet. The condition for the power supply should actually be VCCA < = VCCB. This also applies to our TCA9517 device. The only reason we spec this, is because our internal circuitry is powered by the VCCB rail and will buffer as soon as VCCB is fully ramped. There is no special sequencing needed otherwise.

    Let me know if there are more questions.

    Thanks,

    Siby