Can MMPF0100F0AEP VGEN6 supplies to VIN1?

[satoshishimoda]

Hi community,

I have a question about MMPF100F0AEP.

Actually, our partner consider using MMPF0100F0AEP VGEN6 (3.3V) for VGEN1 supply.

I think VGEN6 output voltage accuracy (+-3%) is good to supply VGEN1 (up to 3.40V input) since 3.3V * 103% = 3.399V.

And I think there is no timing issue since VGEN6 turn-on time is up to 500 us, it is sufficient to supply VGEN1 (SEQ=9) from VGEN6 (SEQ=8).

However, I have concern about start-up overshoot.

VGEN6's start-up overshoot(max) is 2.0%, so in worst case, VGEN6 voltage will be 3.3V * 103%(voltage accuracy) * 102% (start-up overshoot) = 3.47V.

It exceeds VIN1 input voltage (up to 3.4V).

On the other hand, in the case of SW4 which is used for VIN1 supply on SABRE-SD, it also exceeds VIN1 input voltage in worst case as following.

3.15V * 106% (in PWM mode) + 66mV (start-up overshoot) = 3.405V

So I'm confused by these calculation.

[Question]

Can we use VGEN6 to supply VIN1?

How should we judge whether each MMPF0100F0AEP output can supply to VIN1 or not?

Best Regards,

Satoshi Shimoda

[igorpadykov · Accepted solution]

HI Satoshi

one can use VGEN6 to supply VIN1, since

VIN1 is rated up to 3.6V, 3.40V is specified data for permanent

operation.

Best regards

igor

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[satoshishimoda]

Hi Igor,

Thank you for your reply.

OK, I understood it is no problem even though the input voltage exceed 3.40V momentarily.

Best Regards,

Satoshi Shimoda