General description The 74HC85; 74HCT85 is a 4-bit magnitude comparator that can be expanded to almost any length.
They perform comparison of two 4-bit binary, BCD or other monotonic codes and present the three possible magnitude results at the outputs (QA>B, QA=B and QA The 4-bit inputs are weighted (A0 to A3 and B0 to B3), where A3 and B3 are the most significant bits.
For proper compare operation the expander inputs (IA>B, IA=B and IAB = LOW and IA=B = HIGH.