User`s guide
68 | P a g e
D. S1 and S2 are closed for tPLH, tPHL, tPHZ, and tPLZ; S1 is open and S2 is closed for tPZH; S1 is closed and S2 is open for
tPZL.
E. All input pulses are supplied by generators having the following characteristics: PRR 1 MHz, ZO50 ; tr and tf 7 ns for
Series
54/74 devices and tr and tf 2.5 ns for Series 54S/74S devices.
F. The outputs are measured one at a time, with one input transition per measurement.
S1
S2
tPHZ
tPZL tPLZ
tPZH
3 V
3 V
0 V
0 V
th
tsu
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Timing
Input
Data
Input
3 V
0 V
Output
Control
(low-level
enabling)
Waveform 1
(see Notes C
and D)
Waveform 2
(see Notes C
and D)
1.5 V
VOH − 0.5 V
VOL + 0.5 V
1.5 V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
1.5 V 1.5 V
1.5 V 1.5 V
1.5 V
1.5 V 1.5 V
1.5 V 1.5 V
1.5 V
1.5 V
tw
1.5 V 1.5 V
1.5 V 1.5 V
1.5 V 1.5 V
VOH
VOL
Figure 1. Load Circuits and Voltage Waveforms
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SDLS029C − DECEMBER 1983 − REVISED JANUARY 2004
POST OFFICE BOX 655303 DALLAS, TEXAS 75265 9
PARAMETER MEASUREMENT INFORMATION
SERIES 54LS/74LS DEVICES
tPHL tPLH
tPLH tPHL
LOAD CIRCUIT
FOR 3-STATE OUTPUTS