TCPP03 Vgs low with 1.8V EN

[AlexanderDaum]

Hello,

I created a custom board using the TCPP03-M20, based mostly on the NUCLEO H7S3 schematic.

The only differences are:

* My uC is using 1.8V, so the EN pin only gets 1.8V

* VCC_VCONN is supplied with 5V instead of 3.3V

* I use a single power path (using Schottky diodes according to the datasheet)

 

When I measured the Vgs voltage supplied by the TCPP03 to the MOSFET, it is only 3V on my board compared to the 5V on the Nucleo board. According to the datasheet this voltage should always be between 4.5 and 5.5V, correct?

Is there anything wrong with my schematic? I would like to get a Vgs of at least 4.5V, as the MOSFET I'm using is designed for that, not for 3V.

[AlexanderDaum]

I solved the issue. The 5MΩ resistor was connected to GND instead of the MOSFET source pin