MC74AC138, MC74ACT138
1−of−8
Decoder/Demultiplexer
T h e M C 7 4 A C 1 3 8 / 7 4 A C T 1 3 8 i s a h i g h−s p e e d 1
−o
f
−8
decoder/demultiplexer. This device is ideally suited for high−speed
bipolar memory chip select address decoding.
The multiple input enables allow parallel expansion to a 1−of−24
decoder using just three MC74AC138/74ACT138 devices or a
1−of−32 decoder using four MC74AC138/74ACT138 devices and one
inverter.
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•
•
•
•
•
w
Demultiplexing Capability
Multiple Input Enable for Easy Expansion
Active LOW Mutually Exclusive Outputs
Outputs Source/Sink 24 mA
′ACT138
Has TTL Compatible Inputs
These devices are available in Pb−free package(s). Specifications herein
apply to both standard and Pb−free devices. Please see our website at
www.onsemi.com for specific Pb−free orderable part numbers, or
contact your local ON Semiconductor sales office or representative.
V
CC
16
O
0
15
O
1
14
O
2
13
O
3
12
O
4
11
O
5
10
O
6
9
16
1
DIP−16
N SUFFIX
CASE 648
16
1
SO−16
D SUFFIX
CASE 751B
16
1
TSSOP−16
DT SUFFIX
CASE 948F
16
1
EIAJ−16
M SUFFIX
CASE 966
1
A
0
2
A
1
3
A
2
4
E
1
5
E
2
6
E
3
7
O
7
8
GND
ORDERING INFORMATION
Device
MC74AC138N
MC74ACT138N
MC74AC138D
MC74ACT138D
Package
PDIP−16
PDIP−16
SOIC−16
SOIC−16
SOIC−16
SOIC−16
TSSOP−16
TSSOP−16
Shipping
25 Units/Rail
25 Units/Rail
48 Units/Rail
48 Units/Rail
2500 Tape & Reel
2500 Tape & Reel
96 Units/Rail
96 Units/Rail
Figure 1. Pinout: 16−Lead Packages Conductors
(Top View)
A
0
A
1
A
2
E
1
E
2
E
3
MC74AC138DR2
MC74ACT138DR2
O
0
O
1
O
2
O
3
O
4
O
5
O
6
O
7
MC74AC138DT
MC74ACT138DT
MC74AC138DTR2
TSSOP−16 2500 Tape & Reel
Figure 2. Logic Symbol
PIN ASSIGNMENT
PIN
A
0
−A
2
E
1
−E
2
E
3
O
0
−O
7
FUNCTION
Address Inputs
Enable Inputs
Enable Input
Outputs
MC74ACT138DTR2 TSSOP−16 2500 Tape & Reel
MC74AC138M
MC74ACT138M
MC74AC138MEL
MC74ACT138MEL
EIAJ−16
EIAJ−16
EIAJ−16
EIAJ−16
50 Units/Rail
50 Units/Rail
2000 Tape & Reel
2000 Tape & Reel
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 6 of this data sheet.
©
Semiconductor Components Industries, LLC, 2006
March, 2006
−
Rev. 6
1
Publication Order Number:
MC74AC138/D
MC74AC138, MC74ACT138
FUNCTIONAL DESCRIPTION
The MC74AC138/74ACT138 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
MC74AC138/74ACT138 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. This multiple enabled function allows easy parallel
expansion of the device to a 1−of−32 (5 lines to 32 lines)
decoder with just four MC74AC138/74ACT138 devices
and
one
inverter
(See
Figure
4).
The
MC74AC138/74ACT138 can be used as an 8−output
demultiplexer 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.
TRUTH TABLE
Inputs
E
1
H
X
X
L
L
L
L
L
L
L
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
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
Outputs
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
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
A
2
A
1
A
0
E
1
E
2
E
3
0
7
NOTE:
0
6
0
5
0
4
0
3
0
2
0
1
0
0
This diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation
delays.
Figure 3. Logic Diagram
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MC74AC138, MC74ACT138
A
0
A
1
A
2
′04
A
3
A
4
H
123
A
0
A
1
A
2
E
A
0
A
1
A
2
123
E
A
0
A
1
A
2
123
E
A
0
A
1
A
2
123
E
0
0
0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
0
0
0
0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
0
0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
0
0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
31
Figure 4. Expansion to 1−of−32 Decoding
MAXIMUM RATINGS*
Symbol
V
CC
V
IN
V
OUT
I
IN
I
OUT
I
CC
T
stg
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Sink/Source Current, per Pin
DC V
CC
or GND Current per Output Pin
Storage Temperature
Value
−0.5
to +7.0
−0.5
to V
CC
+0.5
−0.5
to V
CC
+0.5
±20
±50
±50
−65
to +150
Unit
V
V
V
mA
mA
mA
°C
*Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recom-
mended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
IN
, V
OUT
t
r
, t
f
Supply Voltage
DC Input Voltage, Output Voltage (Ref. to GND)
Input Rise and Fall Time (Note 1)
′AC
Devices except Schmitt Inputs
Input Rise and Fall Time (Note 2)
′ACT
Devices except Schmitt Inputs
Junction Temperature (PDIP)
Operating Ambient Temperature Range
Output Current
−
High
Output Current
−
Low
V
CC
@ 3.0 V
V
CC
@ 4.5 V
V
CC
@ 5.5 V
V
CC
@ 4.5 V
V
CC
@ 5.5 V
Parameter
′AC
′ACT
Min
2.0
4.5
0
−
−
−
−
−
−
−40
−
−
Typ
5.0
5.0
−
150
40
25
10
8.0
−
25
−
−
Max
6.0
5.5
V
CC
−
−
−
−
−
140
85
−24
24
ns/V
°C
°C
mA
mA
ns/V
Unit
V
V
t
r
, t
f
T
J
T
A
I
OH
I
OL
1. V
IN
from 30% to 70% V
CC
; see individual Data Sheets for devices that differ from the typical input rise and fall times.
2. V
IN
from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.
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MC74AC138, MC74ACT138
DC CHARACTERISTICS
74AC
Symbol
Parameter
V
CC
(V)
T
A
= +25°C
Typ
V
IH
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
V
OL
Maximum Low Level
Output Voltage
3.0
4.5
5.5
3.0
4.5
5.5
I
IN
I
OLD
I
OHD
I
CC
Maximum Input
Leakage Current
†Minimum Dynamic
Output Current
Maximum Quiescent
Supply Current
5.5
5.5
5.5
5.5
1.5
2.25
2.75
1.5
2.25
2.75
2.99
4.49
5.49
−
−
−
0.002
0.001
0.001
−
−
−
−
−
−
−
74AC
T
A
=
−40°C
to
+85°C
Unit
Conditions
Guaranteed Limits
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
2.56
3.86
4.86
0.1
0.1
0.1
0.36
0.36
0.36
±0.1
−
−
8.0
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
2.46
3.76
4.76
0.1
0.1
0.1
0.44
0.44
0.44
±1.0
75
−75
80
V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
I
OUT
=
−50
μA
V
IL
V
V
OH
V
V
*V
IN
= V
IL
or V
IH
−12
mA
I
OH
−24
mA
−24
mA
I
OUT
= 50
μA
V
V
*V
IN
= V
IL
or V
IH
12 mA
I
OL
24 mA
24 mA
V
I
= V
CC
, GND
V
OLD
= 1.65 V Max
V
OHD
= 3.85 V Min
V
IN
= V
CC
or GND
μA
mA
mA
μA
*All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
NOTE: I
IN
and I
CC
@ 3.0 V are guaranteed to be less than or equal to the respective limit @ 5.5 V V
CC
.
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MC74AC138, MC74ACT138
AC CHARACTERISTICS
(For Figures and Waveforms
−
See Section 3 of the ON Semiconductor FACT Data Book, DL138/D)
74AC
Symbol
Parameter
V
CC
*
(V)
Min
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
Propagation Delay
A
n
to O
n
Propagation Delay
A
n
to O
n
Propagation Delay
E
1
or E
2
to O
n
Propagation Delay
E
1
or E
2
to O
n
Propagation Delay
E
3
to O
n
Propagation Delay
E
3
to O
n
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
T
A
= +25°C
C
L
= 50 pF
Typ
8.5
6.5
8.0
6.0
11.0
8.0
9.5
7.0
11.0
8.0
8.5
6.0
Max
13.0
9.5
12.5
9.0
15.0
11.0
13.5
9.5
15.5
11.0
13.0
8.0
74AC
T
A
=
−40°C
to +85°C
C
L
= 50 pF
Min
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.0
Max
15.0
10.5
14.0
10.5
16.0
12.0
15.0
10.5
16.5
12.5
14.0
9.5
ns
ns
ns
ns
ns
ns
3−6
3−6
3−6
3−6
3−6
3−6
Unit
Fig.
No.
*Voltage Range 3.3 V is 3.3 V
±0.3
V.
*Voltage Range 5.0 V is 5.0 V
±0.5
V.
DC CHARACTERISTICS
74ACT
Symbol
Parameter
V
CC
(V)
T
A
= +25°C
Typ
V
IH
V
IL
V
OH
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
4.5
5.5
4.5
5.5
4.5
5.5
4.5
5.5
V
OL
Maximum Low Level
Output Voltage
4.5
5.5
4.5
5.5
I
IN
ΔI
CCT
I
OLD
I
OHD
I
CC
Maximum Input
Leakage Current
Additional Max. I
CC
/Input
†Minimum Dynamic
Output Current
Maximum Quiescent
Supply Current
5.5
5.5
5.5
5.5
5.5
1.5
1.5
1.5
1.5
4.49
5.49
−
−
0.001
0.001
−
−
−
0.6
−
−
−
74ACT
T
A
=
−40°C
to
+85°C
Unit
Conditions
Guaranteed Limits
2.0
2.0
0.8
0.8
4.4
5.4
3.86
4.86
0.1
0.1
0.36
0.36
±0.1
−
−
−
8.0
2.0
2.0
0.8
0.8
4.4
5.4
3.76
4.76
0.1
0.1
0.44
0.44
±1.0
1.5
75
−75
80
V
V
V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
I
OUT
=
−50
μA
*V
IN
= V
IL
or V
IH
−24
mA
I
OH
−24
mA
I
OUT
= 50
μA
*V
IN
= V
IL
or V
IH
24 mA
I
OL
24 mA
V
I
= V
CC
, GND
V
I
= V
CC
−
2.1 V
V
OLD
= 1.65 V Max
V
OHD
= 3.85 V Min
V
IN
= V
CC
or GND
V
V
V
μA
mA
mA
mA
μA
*All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
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