Hello everyone,
My team has experienced strange behavior of TPS53353 in design of 12V -> 3V3 power supply.. We use power good signal (PG) from the 12V -> 5V DC-DC to enable 3V3 stage as presented in the image below.
When we get (PG) signal from the 5V power supply we can measure 5.14V on R745 (EN pin of TPS53353) while we have 4.98V on 5V rail (R484). This problem is observed on several boards (TPS53353 chips).
I removed R745 (connecting 5V PG and 3V3 EN) and in that case PG signal is slightly lower than voltage on 5V rail (as expected). So I thik that this is caused by TPS53353. Other that this 3V3 power supply is working as expected.
Does anyone have any explanation for this?
Design of 3V3 power supply:
