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HD74HC668, HD74HC669
Synchronous UP/Down Decade Counter Synchronous Up/Down 4-bit binary Counter
REJ03D0638-0200 (Previous ADE-205-520)
Rev.2.00 Mar 30, 2006
Description
This synchronous presettable decade counter features an internal carry look-ahead for cascading in high-speed counting applications. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable inputs and internal gating. This mode of operation helps eliminate the output counting spikes that are normally associated with asynchronous (ripple-clock) counters.
A buffered clock input triggers the four master-slave flip-flops on the rising (positive going) edge of the clock waveform.
HD74HC668 Datasheet
