4 Bit Magnitude Comparator

The 74HC85 is a 4-Bit Magnitude Comparator that may be expanded to handle comparisons of almost any length. It compares two 4-bit binary, BCD, or other monotonic codes, presenting three possible magnitude results: QA>B, QA=B, and QAB. It also provides IA=B and IAB outputs, with IA=B being LOW and IAB being HIGH.

Multiple units can be cascaded to handle words bigger than 4 bits by connecting the outputs QAB and QA=B to the corresponding inputs of the significant comparator. As a result, the comparator's capabilities can be expanded to handle longer word lengths as needed.