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TCA9548A VCC Ramp Rates

Other Parts Discussed in Thread: TCA9548A

Hello,

Our customer use the TCA9548A, have a question about VCC ramp rates.

It is mentioned Recommended Supply Sequencing and Ramp Rates on the DS P22.

I understand there is maximum rate of rise time.

Why is there minimum rate? and Why is there fall time?

I think these rates are no impact on POR.

The customer can not accept the minimum rates especially fall time as 1msec.

Best Regards,

Naoki Aoyama

  • Hello Aoymoa-san,

    If the fall rate or rise rate of the device are not satisfied, it is possible that a POR will be missed. However, the fall rate is not quite as critical as the rise rate (if the voltage goes to 0V). If the voltage is just falling down to VPOR(min), then the fall rate is more of a requirement, because the POR circuitry will be powered the entire time and looks at the fall rate.  The min fall time also is there to ensure that fast transients don't inadvertently put the part in POR. 

    Sincerely,

    -Francis Houde