The ’HC85 and ’HCT85 are high speed magnitude comparators that use silicon-gate CMOS technology to achieve operating speeds similar to LSTTL with the low power consumption of standard CMOS integrated circuits.

These 4-bit devices compare two binary, BCD, or other monotonic codes and present the three possible magnitude results at the outputs (A > B, A < B, and A = B). The 4-bit input words are weighted (A0 to A3 and B0 to B3), where A3 and B₃ are the most significant bits.

The devices are expandable without external gating, in both serial and parallel fashion. The upper part of the truth table indicates operation using a single device or devices in a serially expanded application. The parallel expansion scheme is described by the last three entries in the truth table.