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AN804
Vishay Siliconix
P-Channel MOSFETs, the Best Choice for High-Side Switching
Historically, p-channel FETs were not considered as useful as their n-channel counterparts. The higher resistivity of p-type silicon, resulting from its lower carrier mobility, put it at a disadvantage compared to n-type silicon. Getting n-type performance out of p-type FETs has meant larger area geometries with correspondingly higher inter-electrode capacitances. Consequently, a truly complementary pair—a p-channel and an n-channel device that match in all parameters—is impossible. Yet, despite its shortcomings, the p-channel MOSFET performs a vital “high-side” switch task that the n-channel simply cannot equal.
AN804 Datasheet
