TPS7A91: PG glitch

Hailiang Zhang

Part Number: TPS7A91

Hi Team,

My customer finds that when the PG is pull up to Vout. There is a glitch at the PG. And the peak value is different as different pull up resistor. Below is the schematic and waveform (@100k pull up). Could you pls help analyze?

Regards,
Hailiang

9 months ago

0 Juliette 9 months ago

TI__Mastermind 18466 points

Hey Hailiang,

Does the problem persist if you disconnect C2329, we believe this may be interacting with it.

Also, for future reference, a large FF capacitor can also cause glitches - however, we don't believe that this is what is happening here.

https://www.ti.com/lit/an/sbva042/sbva042.pdf

Best,

Juliette

0 Hailiang Zhang 9 months ago in reply to Juliette

TI__Expert 5575 points

Hi Juliette,

Problem still persist when disconnect C2329。About cff value, could you pls advise？

Hailiang Zhang said:
And the peak value is different as different pull up resistor.

Also, can you explain the impact of R3486 resistance value on PG waveform?

Regards,
Hailiang

0 Juliette 9 months ago in reply to Hailiang Zhang

TI__Mastermind 18466 points

Hello Hailiang,

How does the waveform look when site C2329 is left open?

How does the waveform look if C2477 is increased to .1uF?

Best,

Juliette

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TPS7A91: PG glitch