SN54221, SN54LS221, SN74221, SN74LS221

DUAL MONOSTABLE MULTIVIBRATORS

WITH SCHMITT TRIGGER INPUTS

SDLS213B − DECEMBER 1983 − REVISED NOVEMBER 2004

12

POST OFFICE BOX 655303

PARAMETER MEASUREMENT INFORMATION

tPHL

tPLH

tPLH

tPHL

3 V

3 V

0 V

0 V

th

tsu

VOLTAGE WAVEFORMS

SETUP AND HOLD TIMES

Timing

Input

Data

Input

High-Level

Pulse

Low-Level

Pulse

tw

VOLTAGE WAVEFORMS

PULSE DURATIONS

Input

Out-of-Phase

Output

3 V

0 V

VOL

VOH

VOH

VOL

In-Phase

Output

VOLTAGE WAVEFORMS

PROPAGATION DELAY TIMES

LOAD CIRCUIT FOR

BI-STATE

TOTEM-POLE OUTPUTS

(see Note B)

VCC

RL

From Output

Under Test

CL = 15 pF

(see Note A)

Test

Point

NOTES: A. CL includes probe and jig capacitance.

B. All diodes are 1N3064 or equivalent.

C. In the examples above, the phase relationships between inputs and outputs have been chosen arbitrarily.

D. All input pulses are supplied by generators having the following characteristics: PRR

≤ 1 MHz, ZO ≈ 50 Ω and, for SN54/74221,

tr ≤ 7 ns, tf ≤ 7 ns, for SN54/74LS221, tr ≤ 15 ns, tf ≤ 6 ns.

E. All measurements are made between the 1.5-V points of the indicated transitions for the SN54/74221 or between the 1.3-V points

for the SN54/74LS221.

Figure 2. Load Circuits and Voltage Waveforms