SN54221, SN54LS221, SN74221, SN74LS221

DUAL MONOSTABLE MULTIVIBRATORS

WITH SCHMITT TRIGGER INPUTS

SDLS213B − DECEMBER 1983 − REVISED NOVEMBER 2004

8

POST OFFICE BOX 655303

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

otherwise noted)

PARAMETER

TEST CONDITIONS†

SN54LS221

SN74LS221

UNIT

PARAMETER

TEST CONDITIONS†

MIN

TYP‡

MAX

MIN

TYP‡

MAX

UNIT

VT+

Positive-going threshold voltage,

B input

VCC = MIN

1

2*

1

2

V

VT−

Negative-going threshold voltage,

B input

VCC = MIN

0.7*

0.9

0.8

0.9

V

VIK

VCC = MIN,

II = −18 mA

−1.5

−1.5

V

VOH

VCC = MIN,

IOH = −400 µA

2.5

3.4

2.7

3.4

V

VOL

VCC = MIN

IOL = 4 mA

0.25

0.4

0.25

0.4

V

VOL

VCC = MIN

IOL = 8 mA

0.35

0.5

V

II

VCC = MAX,

VI = 7 V

0.1

0.1

mA

IIH

VCC = MAX,

VI = 2.7 V

20

20

µA

IIL

A input

VCC = MAX,

VI = 0.4 V

−0.4

−0.4

mA

IIL

CLR, B input

VCC = MAX,

VI = 0.4 V

−0.8

−0.8

mA

IOS§

VCC = MAX

−20

−100

−20

−100

mA

ICC

Quiescent

VCC = MAX

4.7

11

4.7

11

mA

ICC

Triggered

VCC = MAX

19

27*

19

27

mA

∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.

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

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

§ Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second.

timing requirements over recommended ranges of supply voltage and operating free-air

temperature

SN54LS221

SN74LS221

UNIT

MIN

MAX

MIN

MAX

UNIT

tw

Pulse duration

A or B

50

50

ns

tw

Pulse duration

CLR

40

40

ns

tsu

Setup time, inactive state¶

CLR

15

15

ns

Rext

External timing resistance

1.4*

70*

1.4

100

k

Ω

Cext

External timing capacitance

0*

1000*

0

1000

µF

Output duty cycle

RT = 2 kΩ

50%

50%

Output duty cycle

RT = MAX Rext

90%

90%

∗ On products compliant to MIL-PRF-38535, this parameter is not production tested.

¶ Inactive-state setup time also is referred to as recovery time.