8-bit Magnitude Comparator
Mar 30, 2006
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.
• High Speed Operation: tpd (P or Q to Output) = 17 ns typ (CL = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
• Ordering Information
DILP-20 pin (JEDEC)
HD74HC688FPEL SOP-20 pin (JEITA)
HD74HC688RPEL SOP-20 pin (JEDEC)
EL (2,000 pcs/reel)
EL (1,000 pcs/reel)
Data P, Q
H : high level
L : low level
X : irrelevant
Rev.2.00, Mar 30, 2006 page 1 of 7