SN54ALS688, SN74ALS688
8-BIT IDENTITY COMPARATORS

SDAS228A – JUNE 1982 – REVISED JANUARY 1995
Copyright  1995, Texas Instruments Incorporated
1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
• Compare Two 8-Bit Words
• Totem-Pole Outputs (P = Q)
• ′ALS688 Are Identical to ′ALS521
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK), and Standard Plastic (N)
and Ceramic (J) 300-mil DIPs

description
These identity comparators perform comparisons
on two 8-bit binary or BCD words and provide
P = Q outputs. These devices have totem-pole
outputs.
The SN54ALS688 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74ALS688 is characterized for
operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OUTPUT
DATA
P, Q
ENABLE
G
P = Q
P = Q L L
P > Q LH
P < Q
XHH
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
G
P0
Q0
P1
Q1
P2
Q2
P3
Q3
GND
V
CC
P = Q
Q7
P7
Q6
P6
Q5
P5
Q4
P4
SN54ALS688 ...J PACKAGE
SN74ALS688 ...DW OR N PACKAGE
(TOP VIEW)
3212019
910111213
4
5
6
7
8
18
17
16
15
14
Q7
P7
Q6
P6
Q5
P1
Q1
P2
Q2
P3
SN54ALS688 . . . FK PACKAGE
(TOP VIEW)
Q0 P0 G
Q4
P5
P
= Q
Q3
GND
P4
V
CC
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.