MM54C90 Overview
Description
The MM54C90 MM74C90 decade counter and the MM54C93 MM74C93 binary counter and 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.
