PMOS or pMOS logic is a family of digital circuits based on p-channel, enhancement mode metal–oxide–semiconductor field-effect transistors (MOSFETs). In the late 1960s and early 1970s, PMOS logic was the dominant semiconductor technology for large-scale integrated circuits before being superseded by NMOS and CMOS devices.
PMOS clock IC, 1974
The metal–oxide–semiconductor field-effect transistor is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. The term metal–insulator–semiconductor field-effect transistor (MISFET) is almost synonymous with MOSFET. Another near-synonym is insulated-gate field-effect transistor (IGFET).
Two power MOSFETs in D2PAK surface-mount packages. Operating as switches, each of these components can sustain a blocking voltage of 120 V in the off state, and can conduct a continuous current of 30 A in the on state, dissipating up to about 100 W and controlling a load of over 2000 W. A matchstick is pictured for scale.
Photomicrograph of two metal-gate MOSFETs in a test pattern. Probe pads for two gates and three source/drain nodes are labeled.
