The 74HC/HCT85 are high-speed Si-gate CMOS devicesand are pin compatible with low power Schottky TTL(LSTTL). They are specified in compliance with JEDECstandard no. 7A. The 74HC/HCT85 are 4-bit magnitude comparators thatcan be expanded to almost any length. They performcomparison of two 4-bit binary, BCD or other monotoniccodes and present the three possible magnitude results atthe outputs (QA>B, QA=B and QA<b). the="" 4-bit="" inputs="" are="" weighted="" (a0="" to="" a3="" and="" b0="" b3),="" where="" b3="" most="" significant="" bits.="" operation="" of="" “85â€Â="" is="" described="" in="" function="" table,="" showing="" all="" possible="" logic="" conditions.="" upper="" part="" table="" describes="" normal="" under="" conditions="" that="" will="" occur="" a="" single="" device="" or="" series="" expansion="" scheme.="" three="" outputs="" mutually="" exclusive.="" lower="" reflect="" feed="" forward="" exist="" parallel="" for="" proper="" compare="" expander="" (ia="">B,IA=B and IA<b) to="" the="" least="" significant="" position="" must="" be="" connected="" as="" follows:="" ia<b="IA">B = = LOW andIA=B = HIGH.For words greater than 4-bits, units can be cascaded byconnecting outputs QA<b, qa="">Î’ and QA=B to thecorresponding inputs of the significant comparator.</b,></b)></b).>
