M74HC191 - STMicroelectronics

M74HC191 4-BIT SYNCHRONOUS UP/DOWN COUNTERS

s The M74HC191 is an high speed CMOS 4-BIT b SYNCHRONOUS UP/DOWN COUNTER O fabricated with silicon gate C2MOS technology. - State changes of the counter are synchronous t(s) with the LOW-to-HIGH transition of the Clock Pulse Input. c An asynchronous parallel load input overrides u counting and loads the data present on the DATA d inputs into the flip-flops, .

Features

91M1R T&R M74HC191RM13TR M74HC191TTR input in multi-stage counters. Control input, Down/ Up, determines whether a circuit counts up or down. A MAX/MIN output and a Ripple Clock output provide overflow/underflow indication and make possible a variety of methods for generating carry/borrow signals in multi-stage counter applications. All inputs are equipped with protection circuits against static discharge and transient excess voltage. Obsolete PIN CONNECTION AND IEC LOGIC SYMBOLS August 2001 1/14 M74HC191 INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION PIN No SYMBOL NAME AND FUNCT.