HD74HC688 Datasheet, PDF (1/9 Pages) Hitachi Semiconductor – 8-bit Magnitude Comparator

HD74HC688
8-bit Magnitude Comparator
Description
The HD74HC688 compares bit for bit two 8-bit words and indicates whether or not they are equal. The
P=Q output indicates equality when it is low.
A single active low enable is provided to facilitate cascading of several packages and enable comparison of
words greater than 8-bits.
This device is useful in memory block decoding applications, where memory block enable signals must be
generated from computer address information.
Features
• High Speed Operation: t_pd (P or Q to Output) = 17 ns typ (C_L = 50 pF
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: V_CC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: I_CC (static) = 4 µA max (Ta = 25°C)
Function Table
Input
Data P, Q
P=Q
P>Q
P<Q
X
Enable G
L
L
L
H
P=Q
L
H
H
H