The MM54HC85/MM74HC85 is a 4-bit magnitude compara-
tor that utilizes advanced silicon-gate CMOS technology. It
is designed for high speed comparison of two four bit words.
This circuit has eight comparison inputs, 4 for each word;
three cascade inputs (AkB, AlB, AeB); and three deci-
sion outputs (AkB, AlB, AeB). The result of a comparison
is indicated by a high level on one of the decision outputs.
Thus it may be determined whether one word is ``greater
than,'' ``less than,'' or ``equal to'' the other word. By con-
necting the outputs of the least significant stage to the cas-
cade inputs of the next stage, words of greater than four bits
can be compared. In addition the least significant stage
must have a high level applied to the AeB input, and a low
level to the AkB, and AlB inputs.
The comparator's outputs can drive 10 low power Schottky
TTL (LS-TTL) equivalent loads, and is functionally, and pin
equivalent to the 54LS85/74LS85. All inputs are protected
from damage due to static discharge by diodes to VCC and
• Typical propagation delay: 27 ns
• Wide operating voltage range: 2±6V
• Low input current: 1 mA maximum
• Low quiescent current: 80 mA maximum (74HC Series)
• Output drive capability: 10 LS-TTL loads