74HC138
1−of−8 Decoder/
Demultiplexer
High−Performance Silicon−Gate CMOS
The 74HC138 is identical in pinout to the LS138. The device inputs
are compatible with standard CMOS outputs; with pullup resistors,
they are compatible with LSTTL outputs.
The HC138 decodes a three−bit Address to one−of−eight active−low
outputs. This device features three Chip Select inputs, two active−low
and one active−high to facilitate the demultiplexing, cascading, and
chip−selecting functions. The demultiplexing function is
accomplished by using the Address inputs to select the desired device
output; one of the Chip Selects is used as a data input while the other
Chip Selects are held in their active states.
Features
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MARKING
DIAGRAMS
16
16
1
SOIC−16
D SUFFIX
CASE 751B
1
16
16
1
TSSOP−16
DT SUFFIX
CASE 948F
1
HC138 = Device Code
A
= Assembly Location
L, WL
= Wafer Lot
Y
= Year
W, WW = Work Week
G or
G
= Pb−Free Package
(Note: Microdot may be in either location)
HC
138
ALYW
G
G
HC138G
AWLYWW
•
•
•
•
•
•
Output Drive Capability: 10 LSTTL Loads
Outputs Directly Interface to CMOS, NMOS and TTL
Operating Voltage Range: 2.0 to 6.0 V
Low Input Current: 1.0
m
A
High Noise Immunity Characteristic of CMOS Devices
In Compliance with the Requirements Defined by JEDEC
Standard No. 7A
•
ESD Performance: HBM
>
2000 V; Machine Model
>
200 V
•
Chip Complexity: 100 FETs or 29 Equivalent Gates
•
These are Pb−Free Devices
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 2 of this data sheet.
©
Semiconductor Components Industries, LLC, 2007
March, 2007
−
Rev. 1
1
Publication Order Number:
74HC138/D
74HC138
A0
A1
A2
1
2
3
15
Y0
14
Y1
13
Y2
12
Y3
11
Y4
10
Y5
9
Y6
7
Y7
A0
A1
A2
CS2
CS3
CS1
Y7
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
ADDRESS
INPUTS
ACTIVE−LOW
OUTPUTS
Figure 1. Pin Assignment
CHIP−
SELECT
INPUTS
CS1
CS2
CS3
6
4
5
PIN 16 = V
CC
PIN 8 = GND
Figure 2. Logic Diagram
FUNCTION TABLE
Inputs
X
X
L
H
H
H
H
H
H
H
H
X
H
X
L
L
L
L
L
L
L
L
H
X
X
L
L
L
L
L
L
L
L
X
X
X
L
L
L
L
H
H
H
H
X
X
X
L
L
H
H
L
L
H
H
X
X
X
L
H
L
H
L
H
L
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
Outputs
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
L
CS1CS2 CS3 A2 A1 A0 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
H = high level (steady state); L = low level (steady state); X = don’t care
ORDERING INFORMATION
Device
74HC138DR2G
74HC138DTR2G
Package
SOIC−16
(Pb−Free)
TSSOP−16*
Shipping
†
2500 / Tape & Reel
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
*This package is inherently Pb−Free.
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2
74HC138
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
MAXIMUM RATINGS
Symbol
V
CC
V
in
I
in
I
out
I
CC
P
D
T
stg
T
L
V
out
Parameter
Value
Unit
V
V
V
mA
mA
mA
mW
_C
_C
260
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
– 0.5 to + 7.0
– 0.5 to V
CC
+ 0.5
– 0.5 to V
CC
+ 0.5
±20
±25
±50
500
450
– 65 to + 150
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Current, per Pin
DC Supply Current, V
CC
and GND Pins
Power Dissipation in Still Air,
Storage Temperature
Lead Temperature, 1 mm from Case for 10 Seconds
(SOIC or TSSOP Package)
SOIC Package†
TSSOP Package†
This device contains protection
circuitry to guard against damage
due to high static voltages or electric
fields. However, precautions must
be taken to avoid applications of any
voltage higher than maximum rated
voltages to this high−impedance cir-
cuit. For proper operation, V
in
and
V
out
should be constrained to the
range GND
v
(V
in
or V
out
)
v
V
CC
.
Unused inputs must always be
tied to an appropriate logic voltage
level (e.g., either GND or V
CC
).
Unused outputs must be left open.
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress
ratings only. Functional operation above the Recommended Operating Conditions is not implied.
Extended exposure to stresses above the Recommended Operating Conditions may affect device
reliability.
†Derating
−
SOIC Package: – 7 mW/_C from 65_ to 125_C
TSSOP Package:
−
6.1 .W/_C from 65_ to 125_C
For high frequency or heavy load considerations, see Chapter 2 of the ON Semiconductor High−Speed CMOS Data Book (DL129/D).
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
in
, V
out
T
A
t
r
, t
f
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage, Output Voltage (Referenced to GND)
Operating Temperature, All Package Types
Input Rise and Fall Time
(Figure 2)
V
CC
= 2.0 V
V
CC
= 4.5 V
V
CC
= 6.0 V
Min
2.0
0
– 55
0
0
0
Max
6.0
V
CC
+ 125
1000
500
400
Unit
V
V
_C
ns
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3
74HC138
DC ELECTRICAL CHARACTERISTICS
(Voltages Referenced to GND)
Symbol
V
IH
Parameter
Minimum High−Level Input
Voltage
Test Conditions
V
out
= 0.1 V or V
CC
– 0.1 V
|I
out
|
v
20
mA
V
CC
(V)
2.0
3.0
4.5
6.0
2.0
3.0
4.5
6.0
2.0
4.5
6.0
3.0
4.5
6.0
2.0
4.5
6.0
3.0
4.5
6.0
6.0
6.0
Guaranteed Limit
−55_C
to 25_C
1.5
2.1
3.15
4.2
0.5
0.9
1.35
1.8
1.9
4.4
5.9
2.48
3.98
5.48
0.1
0.1
0.1
0.26
0.26
0.26
±0.1
4
v
85_C
1.5
2.1
3.15
4.2
0.5
0.9
1.35
1.8
1.9
4.4
5.9
2.34
3.84
5.34
0.1
0.1
0.1
0.33
0.33
0.33
±1.0
40
v
125_C
1.5
2.1
3.15
4.2
0.5
0.9
1.35
1.8
1.9
4.4
5.9
2.20
3.70
5.20
0.1
0.1
0.1
0.40
0.40
0.40
±1.0
40
mA
mA
V
Unit
V
V
IL
Maximum Low−Level Input
Voltage
V
out
= 0.1 V or V
CC
– 0.1 V
|I
out
|
v
20
mA
V
V
OH
Minimum High−Level Output
Voltage
V
in
= V
IH
or V
IL
|I
out
|
v
20
mA
V
in
= V
IH
or V
IL
|I
out
|
v
2.4 mA
|I
out
|
v
4.0 mA
|I
out
|
v
5.2 mA
V
V
OL
Maximum Low−Level Output
Voltage
V
in
= V
IH
or V
IL
|I
out
|
v
20
mA
V
in
= V
IH
or V
IL
|I
out
|
v
2.4 mA
|I
out
|
v
4.0 mA
|I
out
|
v
5.2 mA
I
in
I
CC
Maximum Input Leakage
Current
Maximum Quiescent Supply
Current (per Package)
V
in
= V
CC
or GND
V
in
= V
CC
or GND
I
out
= 0
mA
NOTE: Information on typical parametric values can be found in Chapter 2 of the ON Semiconductor High−Speed CMOS Data Book
(DL129/D).
AC ELECTRICAL CHARACTERISTICS
(C
L
= 50 pF, Input t
r
= t
f
= 6.0 ns)
Symbol
t
PLH
,
t
PHL
Parameter
Maximum Propagation Delay, Input A to Output Y
(Figures 1 and 4)
V
CC
(V)
2.0
3.0
4.5
6.0
2.0
3.0
4.5
6.0
2.0
3.0
4.5
6.0
2.0
3.0
4.5
6.0
−
Guaranteed Limit
−55_C
to 25_C
135
90
27
23
110
85
22
19
120
90
24
20
75
30
15
13
10
v
85_C
170
125
34
29
140
100
28
24
150
120
30
26
95
40
19
16
10
v
125_C
205
165
41
35
165
125
33
28
180
150
36
31
110
55
22
19
10
Unit
ns
t
PLH
,
t
PHL
Maximum Propagation Delay, CS1 to Output Y
(Figures 2 and 4)
ns
t
PLH
,
t
PHL
Maximum Propagation Delay, CS2 or CS3 to Output Y
(Figures 3 and 4)
ns
t
TLH
,
t
THL
Maximum Output Transition Time, Any Output
(Figures 2 and 4)
ns
C
in
Maximum Input Capacitance
pF
NOTE: For propagation delays with loads other than 50 pF, and information on typical parametric values, see Chapter 2 of the ON
Semiconductor High−Speed CMOS Data Book (DL129/D).
Typical @ 25°C, V
CC
= 5.0 V
C
PD
Power Dissipation Capacitance (Per Package)*
55
pF
* Used to determine the no−load dynamic power consumption: P
D
= C
PD
V
CC2
f + I
CC
V
CC
. For load considerations, see Chapter 2 of the
ON Semiconductor High−Speed CMOS Data Book (DL129/D).
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4
74HC138
SWITCHING WAVEFORMS
VALID
INPUT A
t
PLH
OUTPUT Y
50%
50%
t
PHL
OUTPUT Y
t
THL
VALID
V
CC
GND
INPUT CS1
t
PHL
t
r
90%
50%
10%
90%
50%
10%
t
f
V
CC
t
PLH
GND
t
TLH
Figure 1.
Figure 2.
TEST POINT
t
f
INPUT
CS2, CS3
90%
50%
10%
t
r
V
CC
t
PLH
GND
DEVICE
UNDER
TEST
OUTPUT
C
L
*
OUTPUT Y
90%
50%
10%
t
PHL
t
THL
t
TLH
*Includes all probe and jig capacitance
Figure 3.
Figure 4. Test Circuit
PIN DESCRIPTIONS
ADDRESS INPUTS
A0, A1, A2 (Pins 1, 2, 3)
Address inputs. For any other combination of CS1, CS2, and
CS3, the outputs are at a logic high.
OUTPUTS
Y0
−
Y7 (Pins 15, 14, 13, 12, 11, 10, 9, 7)
Address inputs. These inputs, when the chip is selected,
determine which of the eight outputs is active−low.
CONTROL INPUTS
CS1, CS2, CS3 (Pins 6, 4, 5)
Chip select inputs. For CS1 at a high level and CS2, CS3
at a low level, the chip is selected and the outputs follow the
Active−low Decoded outputs. These outputs assume a
low level when addressed and the chip is selected. These
outputs remain high when not addressed or the chip is not
selected.
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