SN74LS221
AC WAVEFORMS
tW(in)
B INPUT
1.3 V
3V
0V
≥60 ns
3V
CLEAR
tPLH
tPHL
0V
Q OUTPUT
VOH
VOL
Q OUTPUT
tPHL
tPLH
VOH
A INPUT IS LOW.
VOL
TRIGGER FROM B, THEN CLEAR — CONDITION 1
3V
B INPUT
0V
≥ 60 ns
3V
CLEAR
1.3 V
0V
VOH
Q OUTPUT
VOL
A INPUT IS LOW.
TRIGGER FROM B, THEN CLEAR — CONDITION 2
3V
B INPUT
≥ 50 ns
≥0
ts
0V
CLEAR
3V
0V
TRIGGERED
Q OUTPUT
VOH
VOL
NOT TRIGGERED
tW(out)
A INPUT IS LOW.
CLEAR OVERRIDING B, THEN TRIGGER FROM B
B INPUT
3V
0V
≥ 50 ns
≥ 50 ns
CLEAR
1.3 V
3V
0V
Q OUTPUT
VOH
VOL
A INPUT IS LOW.
TRIGGERING FROM POSITIVE TRANSITION OF CLEAR
Figure 1.
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