The LCX138 high-speed 1-of-8 decoder/demultiplexer
accepts three binary weighted inputs (A
0
, A
1
, A
2
) and,
when enabled, provides eight mutually exclusive active-
LOW outputs (O
0
–O
7
). The LCX138 features three Enable
inputs, two active-LOW (E
1
, E
2
) and one active-HIGH (E
3
).
All outputs will be HIGH unless E
1
and E
2
are LOW and E
3
is HIGH. The LCX138 can be used as an 8-output demulti-
plexer by using one of the active LOW Enable inputs as the
data input and the other Enable inputs as strobes. The
Enable inputs which are not used must be permanently tied
to their appropriate active-HIGH or active-LOW state.
(Top Through View)
(Bottom View)
Truth Table
Inputs
E
1
H
X
X
L
L
L
L
L
L
L
L
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Outputs
A
1
X
X
X
L
L
H
H
L
L
H
H
A
2
X
X
X
L
L
L
L
H
H
H
H
O
0
H
H
H
L
H
H
H
H
H
H
H
O
1
H
H
H
H
L
H
H
H
H
H
H
O
2
H
H
H
H
H
L
H
H
H
H
H
O
3
H
H
H
H
H
H
L
H
H
H
H
O
4
H
H
H
H
H
H
H
L
H
H
H
O
5
H
H
H
H
H
H
H
H
L
H
H
O
6
H
H
H
H
H
H
H
H
H
L
H
O
7
H
H
H
H
H
H
H
H
H
H
L
E
2
X
H
X
L
L
L
L
L
L
L
L
E
3
X
X
L
H
H
H
H
H
H
H
H
A
0
X
X
X
L
H
L
H
L
H
L
H
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2
74LCX138
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
3
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74LCX138
Absolute Maximum Ratings
(Note 3)
Symbol
V
CC
V
I
V
O
I
IK
I
OK
I
O
I
CC
I
GND
T
STG
Parameter
Supply Voltage
DC Input Voltage
DC Output Voltage
DC Input Diode Current
DC Output Diode Current
DC Output Source/Sink Current
DC Supply Current per Supply Pin
DC Ground Current per Ground Pin
Storage Temperature
Value
Conditions
Units
V
V
Output in HIGH or LOW State (Note 4)
V
I
<
GND
V
O
<
GND
V
O
>
V
CC
V
mA
mA
mA
mA
mA
−
0.5 to
+
7.0
−
0.5 to
+
7.0
−
0.5 to V
CC
+
0.5
−
50
−
50
+
50
±
50
±
100
±
100
−
65 to
+
150
°
C
Recommended Operating Conditions
(Note 5)
Symbol
V
CC
V
I
V
O
I
OH
/I
OL
Supply Voltage
Input Voltage
Output Voltage
Output Current
HIGH or LOW State
V
CC
=
3.0V to 3.6V
V
CC
=
2.7V to 3.0V
V
CC
=
2.3V to 2.7V
T
A
Free-Air Operating Temperature
Input Edge Rate, V
IN
=
0.8V to 2.0V, V
CC
=
3.0V
Parameter
Operating
Data Retention
Min
2.0
1.5
0.0
0.0
Max
3.6
3.6
5.5
V
CC
Units
V
V
V
mA
±
24.0
±
12.0
±
8.0
−
40.0
0.0
85.0
10.0
°
C
ns/V
∆
t/
∆
V
Note 3:
The Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated
at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the Absolute Maximum Ratings. The “Recom-
mended Operating Conditions” table will define the conditions for actual device operation.
Note 4:
I
O
Absolute Maximum Rating must be observed.
Note 5:
Unused inputs must be held HIGH or LOW. They may not float.
DC Electrical Characteristics
Symbol
V
IH
V
IL
V
OH
Parameter
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Voltage
I
OH
= −100 µA
I
OH
= -8 mA
I
OH
= −12
mA
I
OH
= −18
mA
I
OH
= −24
mA
V
OL
LOW Level Output Voltage
I
OL
=
100
µA
I
OL
= 8mA
I
OL
=
12 mA
I
OL
=
16 mA
I
OL
=
24 mA
I
I
I
OFF
I
CC
∆I
CC
Input Leakage Current
Power-Off Leakage Current
Quiescent Supply Current
Increase in I
CC
per Input
0
≤
V
I
≤
5.5V
V
I
or V
O
=
5.5V
V
I
=
V
CC
or GND
3.6V
≤
V
I
≤
5.5V
V
IH
=
V
CC
−0.6V
Conditions
V
CC
(V)
2.3 to 2.7
2.7 to 3.6
2.3 to 2.7
2.7 to 3.6
2.3 to 3.6
2.3
2.7
3.0
3.0
2.3 to 3.6
2.3
2.7
3.0
3.0
2.3 to 3.6
0.0
2.3 to 3.6
2.3 to 3.6
2.3 to 3.6
V
CC
−
0.2
1.8
2.2
2.4
2.2
0.2
0.6
0.4
0.4
0.55
±5.0
10.0
10.0
±10.0
500
µA
µA
µA
µA
V
V
T
A
= −40°C
to
+85°C
Min
1.7
2.0
0.7
0.8
Max
V
V
Units
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4
74LCX138
AC Electrical Characteristics
T
A
= −40°C
to
+85°C,
R
L
=
500Ω
Symbol
Parameter
V
CC
=
3.3V
±
0.3V
C
L
=
50pF
Min
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
OSHL
t
OSLH
Propagation Delay
An to Qn
Propagation Delay
E3 to Qn
Propagation Delay
E1 or E2 to Qn
Output to Output Skew (Note 6)
1.5
1.5
1.5
1.5
1.5
1.5
Max
6.0
6.0
6.5
6.5
6.0
6.0
1.0
1.0
V
CC
=
2.7V
C
L
=
50pF
Min
1.5
1.5
1.5
1.5
1.5
1.5
Max
7.0
7.0
7.5
7.5
7.0
7.0
V
CC
=
2.5V
±
0.2V
C
L
=
30pF
Min
1.5
1.5
1.5
1.5
1.5
1.5
Max
7.2
7.2
8.4
8.4
7.2
7.2
ns
ns
ns
ns
Units
Note 6:
Skew is defined as the absolute value of the difference between the actual propagation delay for any two separate outputs of the same device. The
specification applies to any outputs switching in the same direction, either HIGH-to-LOW (t
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