The voltage drop is directly related to Rds(on), as the MOSFET behaves like a low-value resistor.estelios:
Rds(on) is not important for me because i will not use battery for Vin.Important is to have the lowest voltage drop possible because the board control dc motors that are rated for 12vdc
If the load current is really 3A, I'd choose something with a higher current rating and lower Rds(on). That device would drop 0.225V and dissipate almost 0.7W at 3A. Unfortunately, I can't see anything better in a SOT-23 (TO-236) package. You could either try an n-channel device with the appropriate circuit or use a p-channel device in a larger package (eg DMP4015SPS-13).estelios:
I want to know if the Vishay SQ2319ES will do the job for me.