SN74F161A
description
This synchronous, presettable, 4-bit binary counter has internal carry look-ahead circuitry for use in high-speed counting designs.
A3 B4 C5 D6 ENP 7
14 QA 13 QB 12 QC 11 QD 10 ENT
Synchronous operation is provided by having all
GND 8
9 LOAD 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 that are normally associated with asynchronous (ripple-clock) counters. However, counting spikes can occur on the ripple-carry (RCO) output. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of CLK.
This counter is fully programmable. That is, it can be preset to any number between 0 and 15. Because presetting is synchronous, a low logic level at the load (LOAD) input disables the counter and causes the outputs to agree with the setup data after the next...
