SN74AS169A

SN54ALS169B, SN54AS169A, SN74ALS169B, SN74AS169A SYNCHRONOUS 4ĆBIT UP/DOWN BINARY COUNTERS Fully Synchronous Operation for Counting and Programming Internal Carry Look-Ahead Circuitry for Fast Counting Carry Output for n-Bit Cascading Fully Independent Clock Circuit Package Options Include Plastic Small-Outline (D) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs description SDAS125B − MARCH 1984 − REVISED DECEMBER 1994 SN54ALS169B, SN54AS169A . . . J PACKAGE SN74ALS169B, SN74AS169A . . . D OR N PACKAGE (TOP VIEW) U/D 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 These synchronous 4-bit up/down binary presettable counters feature an internal carry look-ahead circuitry for cascading in high-speed counting applications. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform. SN54ALS169B, SN54AS169A . . . FK PACKAGE (TOP VIEW) CLK U/D NC VCC RCO 3 2 1 20 19 A4 18 QA B5 17 QB NC 6 16 NC C7 15 QC D 8 14 9 10 11 12 13 QD ENP GND NC LOAD ENT These counters are fully programmable;...