SN54LVC138A, SN74LVC138A
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCAS291T – MARCH 1993 – REVISED JULY 2005
www.ti.com
PARAMETER MEASUREMENT INFORMATION
V
LOAD
From Output
Under Test
C
L
(see Note A)
R
L
S1
Open
GND
R
L
TEST
t
PLH
/t
PHL
t
PLZ
/t
PZL
t
PHZ
/t
PZH
S1
Open
V
LOAD
GND
LOAD CIRCUIT
INPUTS
V
CC
1.8 V
±
0.15 V
2.5 V
±
0.2 V
2.7 V
3.3 V
±
0.3 V
V
I
V
CC
V
CC
2.7 V
2.7 V
t
r
/t
f
≤2
ns
≤2
ns
≤2.5
ns
≤2.5
ns
V
M
V
CC
/2
V
CC
/2
1.5 V
1.5 V
V
LOAD
2
×
V
CC
2
×
V
CC
6V
6V
C
L
30 pF
30 pF
50 pF
50 pF
R
L
1 kΩ
500
Ω
500
Ω
500
Ω
V
∆
0.15 V
0.15 V
0.3 V
0.3 V
V
I
Timing Input
t
w
V
I
Input
V
M
V
M
0V
VOLTAGE WAVEFORMS
PULSE DURATION
V
I
Input
t
PLH
Output
t
PHL
V
M
V
M
V
M
V
M
0V
t
PHL
V
OH
V
M
V
OL
t
PLH
V
OH
Output
V
M
V
OL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
INVERTING AND NONINVERTING OUTPUTS
Output
Waveform 2
S1 at GND
(see Note B)
Output
Control
t
PZL
Output
Waveform 1
S1 at V
LOAD
(see Note B)
t
PZH
V
M
V
M
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
V
I
V
M
V
M
0V
t
PLZ
V
LOAD
/2
V
OL
+ V
∆
t
PHZ
V
OH
− V
∆
V
OH
≈0
V
V
OL
Data Input
t
su
V
M
t
h
V
I
V
M
0V
V
M
0V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
LOW- AND HIGH-LEVEL ENABLING
NOTES: A. C
L
includes probe and jig capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low, except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high, except when disabled by the output control.
C. All input pulses are supplied by generators having the following characteristics: PRR
≤
10 MHz, Z
O
= 50
Ω.
D. The outputs are measured one at a time, with one transition per measurement.
E. t
PLZ
and t
PHZ
are the same as t
dis
.
F. t
PZL
and t
PZH
are the same as t
en
.
G. t
PLH
and t
PHL
are the same as t
pd
.
H. All parameters and waveforms are not applicable to all devices.
Figure 1. Load Circuit and Voltage Waveforms
8
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