NXP Semiconductors
74HC238; 74HCT238
3-to-8 line decoder/demultiplexer
V
I
negative
pulse
0V
t
W
90 %
V
M
10 %
t
f
t
r
t
r
t
f
90 %
V
M
10 %
t
W
V
M
V
M
V
I
positive
pulse
0V
V
CC
V
CC
PULSE
GENERATOR
VI
VO
RL
S1
DUT
RT
CL
open
001aad983
Test data is given in
Definitions for test circuit:
R
T
= Termination resistance should be equal to output impedance Z
o
of the pulse generator.
C
L
= Load capacitance including jig and probe capacitance.
R
L
= Load resistance.
S1 = Test selection switch
Fig 8. Load circuit for measuring switching times
Table 9.
Type
74HC238
74HCT238
Test data
Input
V
I
V
CC
3V
t
r
, t
f
6 ns
6 ns
Load
C
L
15 pF, 50 pF
15 pF, 50 pF
R
L
1 kΩ
1 kΩ
S1 position
t
PHL
, t
PLH
open
open
74HC_HCT238_3
© NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 03 — 16 July 2007
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