DM54LS161A

54LS161A DM54LS161A DM74LS161A 54LS163A DM54LS163A DM74LS163A Synchronous 4-Bit Binary Counters May 1992 54LS161A DM54LS161A DM74LS161A 54LS163A DM54LS163A DM74LS163A Synchronous 4-Bit Binary Counters General Description These synchronous presettable counters feature an internal carry look-ahead for application in high-speed counting designs The LS161A and LS163A are 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 flipflops clocked simultaneously so that the outputs change coincident with each other when so instructed by the countenable 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 These counters are fully programmable that is the outputs may be preset to either level As presetting is synchronous setting up a low level at the load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse regardless of the levels of the enable input The clear function for the LS161A is asynchronous and a low level at the clear input sets all four of the flip-flop outputs low regardless of the levels of clock load or enable inputs The clear function for the LS163A is synchronous an...