The MM54C90 and MM74C90 are 4-bit decade counters, and the MM54C93 and MM74C93 are 4-bit binary counters. They are complementary MOS (CMOS) integrated circuits constructed with N- and P-channel enhancement mode transistors. The 4-bit decade counter can reset to zero or preset to nine by applying appropriate logic level on the R01, R02, R91 and R92 inputs. Also, a separate flip-flop on the A-bit enables the user to operate it as a divide-by-2, 5 or 10 frequency counter. The 4-bit binary counter can be reset to zero by applying high logic level on inputs R01 and R02, and a separate flip-flop on the A-bit enables the user to operate it as a divide-by-2, -8 or -16 divider. Counting occurs on the negative going edge of the input pulse. All inputs are protected against static discharge damage.