Texas Instruments JM38510-31402B2A, JM38510-31402BFA, JM38510-31402BEA, SN54221J, SN54LS221J Datasheet

...

SN54221, SN54LS221, SN74221, SN74LS221

DUAL MONOSTABLE MULTIVIBRATORS

WITH SCHMITT-TRIGGER INPUTS

SDLS213A – DECEMBER 1983 – REVISED FEBRUARY 1998

Dual Versions of Highly Stable SN54121 and SN74121 One Shots

SN54221 and SN74221 Demonstrate Electrical and Switching Characteristics That Are Virtually Identical to the SN54121 and SN74121 One Shots

Pinout Is Identical to the SN54123, SN74123, SN54LS123, and SN74LS123

Overriding Clear Terminates Output Pulse

Package Options Include Plastic Small-Outline (D), Shrink Small-Outline (DB) Packages, Ceramic Chip Carriers (FK) and Flat Packs (W), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs

MAXIMUM

OUTPUT

TYPE

SN54221 21 SN74221 28 SN54LS221 49 SN74LS221 70

PULSE

LENGTH(S)

description

The ’221 and ’LS221 devices are monolithic dual multivibrators with performance characteristics virtually identical to those of the ’121 devices. Each multivibrator features a negative-transitiontriggered input and a positive-transition-triggered input, either of which can be used as an inhibit input.

SN54221, SN54LS221 ...J OR W PACKAGE

SN74221 ...N PACKAGE

SN74LS221 . . . D, DB, OR N PACKAGE

ext/Cext

SN54LS221 . . . FK PACKAGE

1A 1B

1CLR

1Q 2Q

ext

GND

(TOP VIEW)

ext/Cext

ext

1Q 2Q 2CLR 2B 2A

ext

GND

18 17 16 15 14

ext

1Q NC 2Q 2CLR

1CLR

ext

1B1ANC

3212019

4 5 6 7 8

10 11 12 13

ext ext

2R /C

NC – No internal connection

Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input pulse. Schmitt-trigger input circuitry (TTL hysteresis) for B input allows jitter-free triggering from inputs with transition rates as slow as 1 V/s, providing the circuit with excellent noise immunity, typically of 1.2 V. A high immunity to V

noise, typically of 1.5 V, is also provided by internal latching circuitry.

Once fired, the outputs are independent of further transitions of the A and B inputs and are a function of the timing components, or the output pulses can be terminated by the overriding clear. Input pulses can be of any duration relative to the output pulse. Output pulse length can be varied from 35 ns to the maximums shown in the above table by choosing appropriate timing components. With R

= 2 kΩ and C

ext

= 0, an output pulse typically of

ext

30 ns is achieved, which can be used as a dc-triggered reset signal. Output rise and fall times are TTL compatible and independent of pulse length. Typical triggering and clearing sequences are shown as a part of the switching characteristics waveforms.

Pulse-width stability is achieved through internal compensation and is virtually independent of VCC and temperature. In most applications, pulse stability is limited only by the accuracy of external timing components.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

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.

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

On products compliant to MIL-PRF-38535, all parameters are tested unless otherwise noted. On all other products, production processing does not necessarily include testing of all parameters.

SN54221, SN54LS221, SN74221, SN74LS221 DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS

SDLS213A – DECEMBER 1983 – REVISED FEBRUARY 1998

description (continued)

Jitter-free operation is maintained over the full temperature and VCC ranges for more than six decades of timing capacitance (10 pF to 10 µF) and more than one decade of timing resistance (2 kΩ to 30 kΩ for the SN54221, 2 kΩ to 40 kΩ for the SN74221, 2 kΩ to 70 kΩ for the SN54LS221, and 2 kΩ to 100 kΩ for the SN74LS221). Throughout these ranges, pulse width is defined by the relationship: t circuits where pulse cutoff is not critical, timing capacitance up to 1000 µF and timing resistance as low as 1.4 kΩ can be used. Also, the range of jitter-free output pulse widths is extended if VCC is held to 5 V and free-air temperature is 25°C. Duty cycles as high as 90% are achieved when using maximum recommended RT. Higher duty cycles are available if a certain amount of pulse-width jitter is allowed.

The variance in output pulse width from device to device typically is less than ±0.5% for given external timing components. An example of this distribution for the ’221 is shown in Figure 3. V ariations in output pulse width versus supply voltage and temperature for the ’221 are shown in Figures 4 and 5, respectively.

Pin assignments for these devices are identical to those of the SN54123/SN74123 or SN54LS123/SN74LS123 so that the ’221 or ’LS221 devices can be substituted for those products in systems not using the retrigger by merely changing the value of R

and/or C

ext

; however, the polarity of the capacitor must be changed.

ext

The SN54221 and SN54LS221 are characterized for operation over the full military temperature range of –55°C to 125°C. The SN74221 and SN74LS221 are characterized for operation from 0°C to 70°C.

(out) = C

extRext

In2 ≈ 0.7 C

extRext

. In

FUNCTION TABLE

(each monostable multivibrator)

INPUTS OUTPUTS

CLR A B Q Q

L X X L H X HXLH

X XLLH H L ↑ H ↓ H

‡

↑

†

Pulsed-output patterns are tested during AC switching at 25°C with R C

ext

‡

This condition is true only if the output of the latch formed by the two NAND gates has been conditioned to the logic 1 state prior to CLR conditioned by taking either A high or B low while CLR

L H

= 80 pF.

going high. This latch is

is inactive (high).

† † † †

= 2 kΩ, and

ext

† †

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

SN54221, SN54LS221, SN74221, SN74LS221

DUAL MONOSTABLE MULTIVIBRATORS

WITH SCHMITT-TRIGGER INPUTS

SDLS213A – DECEMBER 1983 – REVISED FEBRUARY 1998

logic symbol

†

This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

Pin numbers shown are for the D, DB, J, N, and W packages.

†

ext/Cext

1A 1B

1CLR

ext

2A 2B

2CLR

ext

1 2

3 14

15 9 10

11 6

R CX

RX/CX

R CX

RX/CX

timing component connections

NOTE: Due to the internal circuit, the R

To C

Terminal

terminal is never more positive than the C

ext/Cext

ext

To R

ext/Cext

Terminal

ext

terminal.

ext

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

SN54221, SN54LS221, SN74221, SN74LS221 DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS

SDLS213A – DECEMBER 1983 – REVISED FEBRUARY 1998

schematics of inputs and outputs

SN54/74221

EQUIVALENT OF EACH INPUT TYPICAL OF ALL OUTPUTS

Input

A Input: Req = 4 kΩ NOM

Input: Req = 2 kΩ NOM

B, CLR

SN54/74LS221

EQUIVALENT OF EACH INPUT TYPICAL OF ALL OUTPUTS

Input

100 Ω NOM

120 Ω NOM

Output

A Input: Req = 25 kΩ NOM

B Input: Req = 15.4 kΩ NOM

CLR

: Req = 12.5 kΩ NOM

Output

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

UNIT

∆v/∆t

Rise or fall of input pulse rate

SN54221, SN54LS221, SN74221, SN74LS221

DUAL MONOSTABLE MULTIVIBRATORS

WITH SCHMITT-TRIGGER INPUTS

SDLS213A – DECEMBER 1983 – REVISED FEBRUARY 1998

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

Supply voltage range, V

Input voltage range, VI (see Note 1): ’LS221 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Package thermal impedance, θJA (see Note 2): D package 113°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage temperature range, T

†

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.

NOTES: 1. The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.

2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace length of zero

7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

’221 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DB package 131°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

N package 78°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

stg

recommended operating conditions

SN54221 SN74221

MIN NOM MAX MIN NOM MAX

V V V I

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

Supply voltage 4.5 5 5.5 4.75 5 5.25 V

High-level input voltage A input 2 2 V

Low-level input voltage A input 0.8 0.8 V

High-level output current –800 –800 µA Low-level output current 16 16 mA

Operating free-air temperature –55 125 0 70 °C

B input 1* 1 V/s A input 1* 1 V/µs

†

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

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