MM54HC390/MM74HC390Dual 4-Bit Decade CounterMM54HC393/MM74HC393Dual 4-Bit Binary CounterGeneral Des criptionThese counter circuits contain independent ripple carrycounters and utilize advanced silicon-gate CMOS technology.The MM54HC390/MM74HC390 incorporate dual decadecounters, each composed of a divide-by-two and a divide-by-five counter. The divide-by-two and divide-by-fivecounters can be cascaded to form dual decade, dual bi-quinary,or various combinations up to a single divide-by-100counter. The MM54HC393/MM74HC393 contain two 4-bitripple carry binary counters, which can be cascaded to createa single divide-by-256 counter.Each of the two 4-bit counters is incremented on the high tolow transition (negative edge) of the clock input, and eachhas an independent clear input. When clear is set high allfour bits of each counter are set to a low level. This enablescount truncation and allows the implementation of divide-by-N counter configurations.Each of the counters outputs can drive 10 low powerSchottky TTL equivalent loads. These counters are functionallyas well as pin equivalent to the 54LS390/74LS390and the 54LS393/74LS393, respectively. All inputs are protectedfrom damage due to static discharge by diodes toVCC and ground.FeaturesY Typical operating frequency: 50 MHzY Typical propagation delay: 13 ns (Ck to QA)Y Wide operating supply voltage range: 2±6VY Low input current: k1 mAY Low quiescent supply current: 80 mA maximum(74HC Series)Y Fanout of 10 LS-TTL loads