SN54ALS520, SN74ALS518, SN74ALS520, SN74ALS521
8-BIT IDENTITY COMPARATORS
SDAS224B – JUNE 1982 – REVISED NOVEMBER 1995
SN54ALS520 . . . J PACKAGE
SN74ALS518, SN74ALS520,
SN74ALS521 . . . DW OR N PACKAGE
• Compare Two 8-Bit Words
• Choice of Totem-Pole or Open-Collector
Outputs
(TOP VIEW)
• SN74ALS518 and ′ALS520 Have 20-kΩ
G
P0
Q0
P1
Q1
P2
Q2
P3
Q3
V
CC
P = Q/P = Q
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
Pullup Resistors on Q Inputs
†
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK), and Standard Plastic (N)
and Ceramic (J) 300-mil DIPs
Q7
P7
Q6
P6
Q5
INPUT
PULLUP
RESISTOR
OUTPUT FUNCTION
AND
CONFIGURATION
13 P5
12 Q4
TYPE
11
GND
P4
SN74ALS518
′ALS520
Yes
Yes
No
P = Q open collector
P = Q totem pole
P = Q totem pole
†
P = Q for SN74ALS518
P = Q for ′ALS520 and SN74ALS521
‡
SN74ALS521
‡
SN74ALS521 is identical to ′ALS688.
SN54ALS520 . . . FK PACKAGE
(TOP VIEW)
description
These identity comparators perform comparisons
on two 8-bit binary or BCD words. The
SN74ALS518 provides P = Q outputs, while the
′ALS520 and SN74ALS521 provide P = Q
outputs. The SN74ALS518 has an open-collector
output. The SN74ALS518 and ′ALS520 feature
20-kΩ pullup resistors on the Q inputs for analog
or switch data.
3
2
1
20 19
18
Q7
P7
Q6
P6
Q5
P1
Q1
P2
Q2
P3
4
5
6
7
8
17
16
15
14
9 10 11 12 13
The SN54ALS520 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74ALS518, SN74ALS520, and
SN74ALS521 are characterized for operation
from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OUTPUTS
DATA ENABLE
P = Q
P = Q
P, Q
P = Q
P > Q
P < Q
X
G
L
H
L
L
L
L
L
H
H
H
L
H
Copyright 1995, Texas Instruments Incorporated
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.
1
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