SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT TRIGGER INPUTS
SDLS213B − DECEMBER 1983 − REVISED NOVEMBER 2004
PARAMETER MEASUREMENT INFORMATION
3V
B†
0V
≥
50 ns
CLR
0V
VOH
Q
VOL
CONDITION 4: TRIGGERING FROM POSITIVE TRANSITION OF CLR
≥
50 ns
3V
tw
3V
A‡
0V
≥
60 ns
3V
CLR
0V
tPLH
Q
VOL
tPHL
Q
VOL
CONDITION 5: TRIGGER FROM A, THEN CLR
tPLH
VOH
tPHL
VOH
3V
A‡
0V
tw
VOH
Q
VOL
tw
Q
VOL
CONDITION 6: TRIGGER FROM A
† A is low.
‡ B and CLR are high.
NOTES: A. Input pulses are supplied by generators having the following characteristics: PRR
≤
1 MHz, ZO
≈
50Ω; for SN54/74221, tr
≤
7 ns,
tf
≤
7 ns, for SN54/74LS221, tr
≤
15 ns, tf
≤
6 ns.
B. 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.
VOH
Figure 1. Switching Characteristics (Continued)
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
11
TI [ TEXAS INSTRUMENTS ]
