SN54ALS21A, SN54AS21, SN74ALS21A, SN74AS21

DUAL 4-INPUT POSITIVE-AND GATES

SDAS085B – APRIL 1982 – REVISED DECEMBER 1994

2

POST OFFICE BOX 655303

7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

– 55

°C to 125°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SN74ALS21A

0

°C to 70°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage temperature range

– 65

°C to 150°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

recommended operating conditions

SN54ALS21A

SN74ALS21A

UNIT

MIN

NOM

MAX

MIN

NOM

MAX

UNIT

VCC

Supply voltage

4.5

5

5.5

4.5

5

5.5

V

VIH

High-level input voltage

2

2

V

VIL

Low-level input voltage

0.8

0.8

V

IOH

High-level output current

– 0.4

– 0.4

mA

IOL

Low-level output current

4

8

mA

TA

Operating free-air temperature

–55

125

0

70

°C

electrical characteristics over recommended operating free-air temperature range (unless

otherwise noted)

PARAMETER

TEST CONDITIONS

SN54ALS21A

SN74ALS21A

UNIT

PARAMETER

TEST CONDITIONS

MIN

TYP‡

MAX

MIN

TYP‡

MAX

UNIT

VIK

VCC = 4.5 V,

II = –18 mA

–1.5

–1.5

V

VOH

VCC = 4.5 V to 5.5 V,

IOH = – 0.4 mA

VCC –2

VCC –2

V

VOL

VCC =4 5V

IOL = 4 mA

0.25

0.4

0.25

0.4

V

VOL

VCC = 4.5 V

IOL = 8 mA

0.35

0.5

V

II

VCC = 5.5 V,

VI = 7 V

0.1

0.1

mA

IIH

VCC = 5.5 V,

VI = 2.7 V

20

20

µA

IIL

VCC = 5.5 V,

VI = 0.4 V

– 0.1

– 0.1

mA

IO§

VCC = 5.5 V,

VO = 2.25 V

–20

–112

–30

–112

mA

ICCH

VCC = 5.5 V,

VI = 4.5 V

0.85

1.4

0.85

1.4

mA

ICCL

VCC = 5.5 V,

VI = 0

1.4

2.3

1.4

2.3

mA

‡ All typical values are at VCC = 5 V, TA = 25°C.

§ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.

switching characteristics (see Figure 1)

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

VCC = 4.5 V to 5.5 V,

CL = 50 pF,

RL = 500 Ω,

TA = MIN to MAX¶

UNIT

(INPUT)

(OUTPUT)

SN54ALS21A

SN74ALS21A

MIN

MAX

MIN

MAX

tPLH

ABCor D

Y

4

18

4

15

ns

tPHL

A, B, C, or D

Y

2

15

2

10

ns

¶ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.