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HD74LS669
Synchronous Up / Down 4-bit Binary Counter
REJ03D0493–0200 Rev.2.00
Feb.18.2005
This synchronous preset table 4-bit binary 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 trigger the four master-slave flip-flops on the rising (positive-going) edge of the clock waveform. This counter is fully programmable; that is, the outputs may each be preset to either level.
HD74LS669 Datasheet
