High Noise Immunity CMOS Driver
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
A driver circuit is proposed with an adjustable hysteresis in its transfer characteristics, allowing an individual setting of the switching threshold for positive and negative input transitions. The output pulse is shaped by a feedback trigger circuit providing steep transitions independently of the slope of the input pulse. A conventional CMOS driver, consisting of two cascaded inverter stages, normally requires a compromise between high noise immunity, which should be about equal for both levels, and good switching characteristics. An improved circuit, as illustrated in the figure, consists of a flip-flop feedback circuit with transistors T1 to T4, which is steered by an input inverter stage with transistors T5 and T6.