MPQ8626 PGOOD Output low level

Hi MPS team,

Now, I have an issue with PGOOD pin, I have read in MPQ8626 datasheet: “If the input supply fails to power the MPQ8626, PGOOD is clamped low, even though PGOOD is tied to an external DC source through a pullup resistor.” In my case, when VIN has supply voltage (12V) and EN pin is driven Low, the PGOOD pin voltage is about 0.8V.
So, my question is: Is my case considered as “input supply fails to power the MPQ8626, PGOOD is clamped low” ?

Sang Nguyen

Hello Sang,

Yes, if the input supply is insufficient, then it will clamp low.

From your description, it is hard to determine what is the cause of the PGOOD low. A PGOOD of 0.8V can just be from the PGOOD pin being pulled up by a 10kOhm.

Can you let us know your operating conditions?
Can you share any waveforms of this behavior?
Can you check if your supply is current limited?
Can you measure if the current through the PG pin matches the value in figure 5 to confirm?
Can you check if there are issues with the output before failure?

Vinh Tran

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