Introduction :

74HC85 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<B).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 IA<B)to the least significant position must be connected as follows: IA<B = IA>B = LOWand IA=B = HIGH. For words greater than 4-bits, units can be cascaded by connecting outputs QA>B, QA=B and QA<B to the corresponding inputs of the significant comparator.Inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.

Features :

• Logic Type: 4-bit Magnitude Comparator.
  
• CMOS low power dissipation.
• atch-up performance exceeds 100 mA per JESD 78 Class II Level B.
• High noise immunity.
• .Operating Voltage: 2V to 6V.
• Logic Case Style: DIP.
• No. of Pins: 16.