ABSTRACT
CMOS logic, which uses complementary n-channel and p-channel MOS transistors, is by far the most important logic family today because of its low standby power, high packing density, and high speed. CMOS is used extensively in high-performance, portable (battery-operated) products such as notebook computers and wireless handheld devices. This chapter shows some basic logic gates with their CMOS circuit realizations. CMOS gates use all enhancement-type transistors for low standby dissipation. In the logic one output state, the transistors of the pull-up branch are conducting but those of the pull-down branch are not. The chapter also presents detailed descriptions of the electrical characteristics for the inverter, and then extends these descriptions to NAND, NOR, and AND-OR-INVERT circuits. Consideration of the voltage-based rules for determining the modes of operation for the two devices reveals that there are five regimes in the voltage transfer characteristic.
