74161 Synchronous Counter high-speed 4-bit synchronous counters. They are edge-triggered, synchronously presettable, and cascadable MSI building blocks for counting, memory addressing, frequency division and other applications.
These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. The 74161 Synchronous Counter is 4-bit binary counters. The carry output is decoded by means of a NOR gate, thus preventing spikes during the normal
counting mode of operation. 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 inputs and internal gating. This mode of operation eliminates the output counting
spikes which are normally associated with asynchronous (ripple clock) counters.
A buffered clock input triggers the four flip-flops on the rising (positive-going) edge of the clock input waveform.