The Harris CD74HC161, CD74HCT161, CD74HC163 and CD74HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The CD74HC161 and CD74HCT161 are asynchronous reset decade and binary counters, respectively; the CD74HC163 and CD74HCT163 devices decade and binary counters, respectively and are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock.