54LS/74LS90

The ’90 is a 4-stage ripple counter containing a high speed flip-flop acting as a divide-by-two and three flip-flops connected as a divideby- five counter.

DESCRIPTION—The’90isa4-stageripplecountercontainingahighspeed flip-flopactingasadivide-by-twoandthreeflip-flopsconnectedasadivideby- fivecounter.ItcanbeconnectedtooperatewithaconventionalBCDoutput patternoritcanbeconnectedtoprovidea50dutycycleoutpu