These synchronous, presettable, 8-bit up/down counters feature 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 coincidentally 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 eight flip-flops on the rising (positive going) edge of the clock waveform.
• Fully Programmable With Synchronous Counting and Loading
• SN74ALS867A and ′AS867 Have Asynchronous Clear; SN74ALS869 and ′AS869 Have Synchronous Clear
• Fully Independent Clock Circuit Simplifies Use
• Ripple-Carry Output for n-Bit Cascading
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (NT) and Ceramic (JT) 300-mil DIPs
