SNJ54LS669J

The SNJ54LS669J from Texas Instruments is a synchronous, presettable, 4-bit binary up/down counter designed for high-speed counting applications. It features internal carry look-ahead circuitry, enabling cascading for n-bit synchronous operations without additional external gating.

This counter operates synchronously, meaning all flip-flops are clocked simultaneously, ensuring outputs change coincidentally and minimizing counting spikes. It utilizes the LS technology family and is rated for military applications with an operating temperature range of -55 to 125°C. The device features buffered outputs and a fully independent clock circuit.

The SNJ54LS669J is fully programmable, allowing outputs to be preset to any level. The load input circuitry facilitates loading with the carry-enable output of cascaded counters. Synchronous loading ensures that the outputs agree with the data inputs after the next clock pulse when the load input is low. Two count-enable inputs (P\ and T\) must be low to enable counting, and the direction of count is controlled by the up/down input.

Packaged in a CDIP (J) configuration, this counter is suitable for demanding environments where reliable synchronous counting is required.