ESP32-POE-ISO ver. C ESP-EN Signal problem

[A2B]

Hello, I have a ESP32-POE-ISO version C, and when I power by USB the voltage level at pin ESP_EN is above 4 volts (4.2V aprox). When I power by PoE I don`t have this problem, the voltage level at pin ESP_EN is 3V3. Reviewing the schematic, the problem is when RTS# pin of U1 (USB to UART) is at high level, I have current between pin 2 and 3 of Q2 with a voltage drop around 0.5V. This is happening because U1 is powered by 5V. For example, I have checked in ESP32-POE version C and I don`t have this problem. This is because between version C and D of ESP32-POE you change the power supply of U1 from 3V3 to 5V. My question is: Can this be a problem for ESP_EN pin? What is the absolute maximum voltage range for this pin? Thank you

[LubOlimex]

It shouldn't be a problem, there is a resistor but the team is looking into it. At least we have encountered 0 issues so far. But we would definitely look into into it, we might place a diode like at the RX and TX lines in future.

The switch from 3.3V to 5V powering of CH340T was to minimize the power consumption when powered by battery.

[A2B]

Ok, thanks for the reply. I also think that it shouldn't be a problem because I have some boards working like this. My only concern is that the ESP_EN input will not tolerate a voltage value above 3V3 and could end up failing. Any news that you find on this, I would appreciate if you would comment on it here.