HD74AC164

HD74AC164/HD74ACT164 Serial-In, Parallel-Out Shift Register Description The HD74AC164/HD74ACT164 is a high-speed 8-bit serial-in/parallel-out shift register. Serial data is entered through a 2-input AND gate synchronous with the Low-to-High transition of the clock. The device features an asynchronous Master Reset which clears the register, setting all outputs Low independent of the clock. Features Outputs Source/Sink 24 mA HD74ACT164 has TTL-Compatible Inputs Pin Arrangement A 1 B 2 Q0 3 Q1 4 Q2 5 Q3 6 GND 7 (Top view) 14 VCC 13 Q7 12 Q6 11 Q5 10 Q4 9 MR 8 CP HD74AC164/HD74ACT164 Logic Symbol A B CP MR Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Pin Names A, B CP MR Q0 to Q7 Data Inputs Clock Pulse Input (Active Rising Edge) Master Reset Input (Active Low) Outputs Functional Description The HD74AC164/HD74ACT164 is an edge-triggered 8-bit shift register with serial data entry and an output from each of the eight stages. Data is entered serially through one of two inputs (A or B); either of these inputs can be used as an active High Enable for data entry through the other inputs. An unused input must be tied High. Each Low-to-High transition on the Clock (CP) input shifts data one place to the right and enters into Q 0 the logical AND of the two data inputs (AB) that existed before the rising clock edge. A Low level on the Master Reset (MR) input overrides all other inputs and clears the register asynchronously, forcing all Q outputs Low. 2 HD74AC164/HD74ACT164 Mode Select Table In...