SN54HC138, SN74HC138
3 LINE TO 8 LINE DECODERS/DEMULTIPLEXERS
SCLS107E − DECEMBER 1982 − REVISED SEPTEMBER 2003
switching characteristics over recommended operating free-air temperature range, C
L
= 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC
2V
A, B, or C
tpd
Enable
Any Y
Any Y
4.5 V
6V
2V
4.5 V
6V
2V
tt
Any
4.5 V
6V
TA = 25°C
MIN
TYP
MAX
67
18
15
66
18
15
38
8
6
180
36
31
155
31
26
75
15
13
SN54HC138
MIN
MAX
270
54
46
235
47
40
110
22
19
SN74HC138
MIN
MAX
225
45
38
195
39
33
95
19
16
ns
ns
UNIT
operating characteristics, T
A
= 25°C
PARAMETER
Cpd
Power dissipation capacitance
TEST CONDITIONS
No load
TYP
85
UNIT
pF
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
Test
Point
CL = 50 pF
(see Note A)
In-Phase
Output
Input
VCC
50%
tPLH
50%
10%
tPHL
Out-of-Phase
Output
90%
50%
10%
tf
90%
tr
Input
50%
10%
90%
90%
VCC
50%
10% 0 V
tf
tPLH
50%
10%
90%
tr
50%
0V
tPHL
90%
VOH
50%
10%
VOL
tf
VOH
VOL
LOAD CIRCUIT
tr
VOLTAGE WAVEFORM
INPUT RISE AND FALL TIMES
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
NOTES: A. CL includes probe and test-fixture capacitance.
B. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR
≤
1 MHz, ZO = 50
Ω,
tr = 6 ns, tf = 6 ns.
C. The outputs are measured one at a time with one input transition per measurement.
D. tPLH and tPHL are the same as tpd.
Figure 1. Load Circuit and Voltage Waveforms
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
5
TI [ TEXAS INSTRUMENTS ]
