CD74AC161 - Texas Instruments

CD74AC161 4-BIT SYNCHRONOUS BINARY COUNTERS

ordering information CD54AC161 . . . F PACKAGE CD74AC161 . . . E OR M PACKAGE (TOP VIEW) CLR 1 CLK 2 A3 B4 C5 D6 ENP 7 GND 8 16 VCC 15 RCO 14 QA 13 QB 12 QC 11 QD 10 ENT 9 LOAD The ’AC161 devices are 4-bit binary counters. These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting These devices are.

Features

e levels of the enable inputs. The clear function is asynchronous. A low level at the clear (CLR) input sets all four of the flip-flop outputs low, regardless of the levels of the CLK, load (LOAD), or enable inputs. The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without additional gating. Instrumental in accomplishing this function are ENP, ENT, and a ripple-carry output (RCO). Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. Enabling RCO produces a high-level pulse while the count is maximum (9 or 15, with QA hi.