SN54ALS520, SN74ALS518, SN74ALS520, SN74ALS521

8-BIT IDENTITY COMPARATORS

SDAS224B – JUNE 1982 – REVISED NOVEMBER 1995

Copyright

1

POST OFFICE BOX 655303

Outputs

Pullup Resistors on Q Inputs

Small-Outline (DW) Packages, Ceramic

Chip Carriers (FK), and Standard Plastic (N)

and Ceramic (J) 300-mil DIPs

TYPE

INPUT

PULLUP

OUTPUT FUNCTION

AND

TYPE

PULLUP

RESISTOR

AND

CONFIGURATION

SN74ALS518

Yes

P = Q open collector

′ALS520

Yes

P = Q totem pole

SN74ALS521‡

No

P = Q totem pole

‡ SN74ALS521 is identical to

′ALS688.

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-k

Ω 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.

FUNCTION TABLE

INPUTS

OUTPUTS

DATA

P, Q

ENABLE

G

P = Q

P = Q

P = Q

L

H

L

P > Q

LL

H

P < Q

LL

H

X

H

L

H

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

Q7

P7

Q6

P6

Q5

P5

Q4

P4

SN54ALS520 ...J PACKAGE

SN74ALS518, SN74ALS520,

SN74ALS521 ... DW OR N PACKAGE

(TOP VIEW)

32 1 20 19

910 11 12 13

4

5

6

7

8

18

17

16

15

14

Q7

P7

Q6

P6

Q5

P1

Q1

P2

Q2

P3

SN54ALS520 . . . FK PACKAGE

(TOP VIEW)

† P = Q for SN74ALS518

P = Q for

′ALS520 and SN74ALS521

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.