the act163 devices are 4-bit binary counters. these synchronous presettable counters feature an internal carry look-ahead for application in high-speed counting designs. synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when instructed by the count-enable (enp ent) inputs and internal gating. this mode of operation eliminates the output counting spikes normally associated with synchronous (ripple-clock) counters. a buffered clock (clk) input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform. the counters are fully programmable; that is they can be preset to any number between 0 and 9 or 15. view all in datasheet