STM32 GPIO NMOS

[jacklin]

What is the maximum current that the STM32 GPIO can withstand when set to open-drain mode and the NMOS is on without getting damaged?

[Ozone]

I think you need to be more specific here.
First, there is no continuous gate current, at least in theory.But driving at high speed / frequency, the gate capacity needs to be charged / discharged, which might require a substantial current.

Second, many MOSFETs require a gate voltage (Uth) beyond 3.3V the MCU cannot achieve. You would need driver circuitry in this case.

[AScha.3]

Just see ds :

 

 

[jacklin]

In fact, my application is like this：

The GPIO port of ST is configured as open - drain, and the port is connected to a π - type filter, that is, a 104 capacitor + a magnetic bead + a 104 capacitor. When the open - drain port is pulled low, the two 104 capacitors will discharge and the current will flow through the lower transistor inside the MCU NMOS. Will this cause the lower transistor to burn out due to over - current?

[AScha.3]

So simply limit the current with a resistor at the pin to 25mA max : R = Upin /25mA

[Andrew Neil]

As @AScha.3 said, the values are in the datasheet.

Note that there is both a per-pin limit, and a total-chip limit.

[TDK]

You should limit it to 20 mA, not 25 mA. The absolute maximum ratings may degrade performance over time.