I’m planning to use the an EPC GaN FET to sink around 30A for a period of around 3 microseconds. The data sheet mentions that the current limit for a 300 microsecond pulse is around 17A. I was wondering if sinking 30A for 1 microsecond would be safe if these pulses happen only once every couple hundred milliseconds.
This will not work. The 17A datasheet number is a test parameter to verify the minimum transconductance limit of the FET in production. In other words, we do not guarantee the FET will support any drain currents higher than 17A regardless of the time duration. The channel will saturate and begin to limit the current above 17A. You need to choose a FET with a pulse rating of 30Amp or greater just to support the current. The SOA curve will limit the power.