CMOS output buffer with pre-drive circuitry to control slew rate of main drive transistors

摘要

A CMOS output buffer comprises an output stage circuit including MOS transistors each having a CMOS structure, for outputting a signal, and an output stage control circuit arranged prior to the output stage circuit. The output stage control circuit includes a pull-up circuit and a pull-down circuit for controlling the gate of the final stage MOS transistor of the MOS transistors so that a speed at which a gate-to-source voltage varies when the final stage MOS transistor is turned on, is slower than a speed at which the gate-to-source voltage varies when the final stage MOS transistor is turned off.