HD74HCT688 Datasheet, PDF (1/8 Pages) Hitachi Semiconductor – 8-bit Magnitude Comparator

HD74HCT688
8-bit Magnitude Comparator
Description
The HD74HCT688 compares bit for bit two 8-bit words and indicate 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
• LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility
• High Speed Operation: t_pd (Data to P=Q) = 18 ns typ (C_L = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: V_CC = 4.5 to 5.5 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: I_CC (static) = 4 µA max (Ta = 25°C)
Function Table
Inputs
Data P, Q
P=Q
P>Q
P<Q
X
Enable G
L
L
L
H
P=Q
L
H
H
H