Texas Instruments SN54ALS520J, SN74ALS518DW, SN74ALS518N, SN74ALS520DW, SN74ALS520DWR Datasheet

SN54ALS520, SN74ALS518, SN74ALS520, SN74ALS521

TYPE

PULLUP

AND

8-BIT IDENTITY COMPARATORS

SDAS224B – JUNE 1982 – REVISED NOVEMBER 1995

• Compare Two 8-Bit Words

• Choice of Totem-Pole or Open-Collector

Outputs

• SN74ALS518 and ′ALS520 Have 20-kΩ

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

INPUT

RESISTOR

SN74ALS518 Yes P = Q open collector
′ALS520 Yes P = Q totem pole
SN74ALS521

‡

SN74ALS521 is identical to ′ALS688.

‡

No P = Q totem pole

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.

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.

OUTPUT FUNCTION

CONFIGURATION

SN54ALS520 ...J PACKAGE

SN74ALS518, SN74ALS520,

SN74ALS521 ...DW OR N PACKAGE

†

P = Q for SN74ALS518
P = Q

SN54ALS520 . . . FK PACKAGE

P1

Q1

P2

Q2

P3

(TOP VIEW)

G

1

P0

2

Q0

3

P1

4

Q1

5

P2

6

Q2

7

P3

8
9

Q3

GND

10

for ′ALS520 and SN74ALS521

(TOP VIEW)

Q0P0G

3212019

4
5
6
7
8

910111213

Q3

P4

20
19
18
17
16
15
14
13
12
11

V

CC

Q4

V

CC

P = Q/P = Q
Q7
P7
Q6
P6
Q5
P5
Q4
P4

18
17
16
15
14

P5 P = Q

Q7
P7
Q6
P6
Q5

GND

†

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.

FUNCTION TABLE

INPUTS

DATA

ENABLE

P, Q

P = Q L H L
P > Q LLH
P < Q LLH

XHLH

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

G

OUTPUTS

P = Q

P = Q

Copyright  1995, Texas Instruments Incorporated

1

SN54ALS520, SN74ALS518, SN74ALS520, SN74ALS521
8-BIT IDENTITY COMPARATORS

SDAS224B – JUNE 1982 – REVISED NOVEMBER 1995

logic symbols

1

G

2

P0

4

P1

6

P2

8

P3

11

P4

13

P5

15

P6

17

P7

3

Q0

5

Q1

7

Q2

9

Q3

12

Q4

14

Q5

16

Q6

18

Q7

†

SN74ALS518

COMP

G1
0

P

7
0

Q

7

1P=Q

19

P = Q

P0
P1
P2
P3
P4
P5
P6

P7
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7

′ALS520

SN74ALS521

1

G

2
4
6
8
11
13
15
17
3
5
7
9
12
14
16
18

G1
0

7
0

7

COMP

P

Q

1P=Q

19

P = Q

†

These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

logic diagrams (positive logic)

17

P7

18

Q7

15

P6

16

Q6

13

P5

14

Q5

11

P4

12

Q4

8

P3

SN54ALS520, SN74ALS518, SN74ALS520, SN74ALS521

8-BIT IDENTITY COMPARATORS

SDAS224B – JUNE 1982 – REVISED NOVEMBER 1995

SN74ALS518

19

P = Q

Q3

P2

Q2

P1

Q1

P0

Q0

9

6

7

4

5

2

3

1

G

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

3