While looking at datasheets of various STM32s and AN4899 (STM32 GPIO Application Note) I was trying to determine the GPIO absolute ratings. There is a consistent value of 25 mA per pin in Absolute Maximum Ratings in all datasheets, but no maximum capacitive load rating. In the AN4899 there is a formula for dynamic current consumption. Judging from the formula (I_dynamic = f_switching * VDD * C_load) I guess it is permitted to connect a capacitive load directly to GPIO as long as the average dynamic current is kept under 25 mA? With capacitive load the GPIO will definitely see spikes of current larger than 25 mA. So the 25mA limit seems to be an average current limit, but it isn't described as such anywhere - only as an absolute maximum rating.
I'd like to drive a MOSFET with about 2-3 nC of gate charge with 100kHz PWM and I'd like to not use any external driver due to limited PCB space. I need to know if I can drive it without any series resistor. According to formula from AN4899 is (way) below 25 mA.
Can anyone guide me to a hard, clearly written description of maximum capacitive load and/or maximum peak current of GPIO in STM32 family?
The exact MCU is not chosen yet, as this question needs an answer before I decide to use STM32 in the project.
