Power Good (PG) pin implementation is out of spec for TPS82140SILR

[GadgetMan-Matt]

Spec sheet for TPS82140SILR specifies PG pin at max 7v and 10mA. As implemented it is exposed to 12v rail via R4 which when pulled low is in excess of 20mA. The sample circuit in the spec sheet suggests it’s driven from Vout which would put it at 5v max.

[FOSV]

Thank you for your feedback on the Power Good circuit of the TPS82140SILR. I’ve reviewed the design and made an adjustment: by using a 1.2k Ω resistor instead of a 500 Ω resistor, the circuit now limits the current on the PG pin to 7.5 mA, which is well within the datasheet’s maximum of 10 mA. The voltage at the PG node remains stable at 3V, ensuring the LED operates correctly while respecting the PG pin’s voltage limit of 7V.

That said, I agree with your observation that it would make more sense to position the Power Good LED on the converter’s output (Vout) instead. This setup would allow for easier troubleshooting by distinguishing between a fault in the DC-DC converter and issues downstream. For now, though, I will keep the current configuration, as it is both functional and compliant with the specifications.