DM74LS390

Each of these DM74LS390 monolithic circuits contains eight masterslave flip-flops and additional gating to implement two individual four-bit counters in a single package. The DM74LS390 incorporates dual divide-by-two and divideby- five counters, which can be used to implement cycle lengths equal to any whole and/or cumulative multiples of 2 and/or 5 up to divide-by-100. When connected as a bi-quinary counter, the separate divide-by-two circuit can be used to provide symmetry (a square wave) at the final output stage. The DM74LS390 has parallel outputs from each counter stage so that any submultiple of the input count frequency is available for system-timing signals.