AM6548: Confirmation on slew rate

Michael

Part Number: AM6548
Other Parts Discussed in Thread: TPS22919-Q1

Per the datasheet for the AM6548, the maximum slew rate is recommended to be less than 100 mV/µs for supplies in general, and less than 40 mV/µs for the VDDA_1P8_SERDES0 supplies. Alternatively, the slew time must be greater than the supply value x 10µs, and greater than supply value x 25µs, respectively.

Just to confirm, this slew rate does apply for both rise and fall times?

4 months ago

0 Michael 4 months ago

Intellectual 325 points

Additional context:

The recommended power solution for the AM6548 uses the PMIC (TPS65941319-Q1) along with several load switches (TPS22919-Q1).

These load switches feature a Quick Output Discharge pin to set the output fall time. Since these are enabled by the PMIC, I was wondering whether it would be appropriate to simply short the load switches' R_QOD to VOUT.

+1 peaves 4 months ago in reply to Michael

TI__Guru 63865 points

I'm able to answer your first question. I will let the person assigned to this thread answer your second question.

The max power supply slew rates requirement defined in the datasheet only applies when the power rails are ramping up. The ESD circuits implemented on the power rails may false trigger, clamping the power rails to VSS if the power rails ramp too fast.

Regards,
Paul

0 Michael 4 months ago in reply to peaves

Intellectual 325 points

Hi Paul,

Are there any requirements on the slew rate for fall times?

Thank you,

Michael

+1 peaves 4 months ago in reply to Michael

TI__Guru 63865 points

No.

0 Michael 4 months ago in reply to peaves

Intellectual 325 points

Thank you

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AM6548: Confirmation on slew rate