Page 1
TECHNICAL DATA
1-of-8 Decoder/Demultiplexer
High-Speed Silicon-Gate CMOS
The IN74ACT138 is identical in pinout to the LS/ALS138,
HC/HCT138. The IN74ACT138 may be used as a level converter for
interfacing TTL or NMOS outputs to High Speed CMOS inputs.
The IN74ACT138 decodes a three-bit Address to one-of-eight
active-lot 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.
•
TTL/NMOS Compatible Input Levels
•
Outputs Directly Interface to CMOS, NMOS, and TTL
•
Operating Voltage Range: 4.5 to 5.5 V
•
Low Input Current: 1.0 µA; 0.1 µA @ 25°C
•
Outputs Source/Sink 24 mA
IN74ACT138
ORDERING INFORMATION
IN74ACT138N Plastic
IN74ACT138D SOIC
TA = -40° to 85° C for all
packages
PIN ASSIGNMENT
LOGIC DIAGRAM
PIN 16 =V
PIN 8 = GND
CC
FUNCTION TABLE
Inputs Outputs
CS1 CS2 CS3 A2 A1 A0 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
X X H
X H X
L X X
H L L
H L L
H L L
H L L
H L L
H L L
H L L
H L L
H = high level (ste ady state)
L = low level (steady state)
X = don’t care
X X X
X X X
X X X
L L L
L L H
L H L
L H H
H L L
H L H
H H L
H H H
H H H H H H H H
H H H H H H H H
H H H H H H H H
L H H H H H H H
H L H H H H H H
H H L H H H H H
H H H L H H H H
H H H H L H H H
H H H H H L H H
H H H H H H L H
H H H H H H H L
158
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IN74ACT138
MAXIMUM RATINGS
*
Symbol Parameter Value Unit
V
CC
V
V
OUT
I
IN
I
OUT
I
CC
P
DC Supply Voltage (Referenced to GND) -0.5 to +7.0 V
DC Input Voltage (Referenced to GND) -0.5 to VCC +0.5 V
IN
DC Output Voltage (Referenced to GND) -0.5 to VCC +0.5 V
DC Input Current, per Pin
DC Output Sink/Source Current, per Pin
DC Supply Current, VCC and GND Pins
Power Dissipation in Still Air, Plastic DIP+
D
SOIC Package+
±
20
±
50
±
50
750
500
Tstg Storage Temperature -65 to +150
T
Lead Temperature, 1 mm from Case for 10 Seconds
L
260
(Plastic DIP or SOIC Package)
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
+Derating - Plastic DIP: - 10 mW/°C from 65° to 125°C
SOIC Package: : - 7 mW/°C from 65° to 125°C
mA
mA
mA
mW
°
C
°
C
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Max Unit
V
CC
VIN, V
OUT
T
J
T
A
I
OH
I
OL
tr, t
f
*
VIN from 0.8 V to 2.0 V
This device c ontains p rote ction ci rcuitr y to guard a gainst damage d ue to high st atic voltages or electr ic
fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated
voltages to this high-impedance circuit. For proper operation, V
GND≤(V
IN
Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or V
Unused outputs must be left open.
DC Supply Voltage (Referenced to GND) 4.5 5.5 V
DC Input Voltage, Output Voltage (Referenced to GND) 0 V
Junction Temperature (PDIP) 140
Operating Temperature, All Package Types -40 +85
Output Current - High -24 mA
Output Current - Low 24 mA
Input Rise and Fall Time
(except Schmitt Inputs)
or V
OUT
)≤VCC.
*
V
V
=4.5 V
CC
=5.5 V
CC
and V
IN
0
0
should be constrained to the range
OUT
10
8.0
CC
V
°
C
°
C
ns/V
CC
).
159
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IN74ACT138
DC ELECTRICAL CHARACTERISTICS
(Voltages Referenced to GND)
Symbol Parameter Test Conditions V
V
Minimum High-Level
IH
V
=0.1 V or VCC-0.1 V 4 .5
OUT
Input Voltage
V
Maximum Low -
IL
V
=0.1 V or VCC-0.1 V 4 .5
OUT
Level Input Voltage
V
OH
Minimum High-Level
I
OUT
≤ -50 µA
Output Voltage
*
VIN=VIH or V
IL
IOH=-24 mA
I
=-24 mA
OH
V
OL
Maximum Low-Level
I
OUT
≤ 50 µA
Output Voltage
*
VIN= VIH or V
IL
IOL=24 mA
I
=24 mA
OL
I
IN
Maximum Input
VIN=VCC or GND 5.5
Leakage Current
∆
I
CCT
I
OLD
Additional Max.
I
/Input
CC
+Minimum Dynamic
V
IN=VCC
V
OLD
- 2.1 V 5.5 1.5 mA
=1.65 V Max 5.5 75 mA
Output Current
I
OHD
+Minimum Dynamic
V
=3.85 V Min 5.5 -75 mA
OHD
Output Current
I
CC
Maximum Quiescent
VIN=VCC or GND 5.5 8.0 80
Supply Current
(per Package)
*
All outputs loaded; thresholds on input associated with output under test.
+Maximum test duration 2.0 ms, one output loaded at a time.
V
5.5
5.5
4.5
5.5
4.5
5.5
4.5
5.5
4.5
5.5
CC
Guaranteed Limits
25 °C-40
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
°
C to
85°C
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
Unit
V
V
V
V
µ
A
µ
A
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IN74ACT138
AC ELECTRICAL CHARACTERISTICS
Symbol Parameter
t
t
t
t
t
t
C
C
PLH
PHL
PLH
PHL
PLH
PHL
IN
PD
Propagation Delay, Input A to Output Y
(Figure 1)
Propagation Delay, Input A to Output Y
(Figure 1)
Propagation Delay, CS2 or CS3 to Output Y
(Figure 3)
Propagation Delay, CS2 or CS3 to Output Y
(Figure 3)
Propagation Delay, CS1 to Output Y (Figure 2) 2.5 12.0 2.0 13.0 ns
Propagation Delay, CS1 to Output Y (Figure 2) 2.0 10.5 1.5 11.5 ns
Maximum Input Capacitance 4.5 4.5 pF
Power Dissipation Capacitance 60 pF
(VCC=5.0 V ± 10%, CL=50pF,Input tr=tf=3.0 ns)
Guaranteed Limits
25 °C-40
°
C to 85°C
Min Max Min Max
1.5 10.5 1.5 11.5 ns
1.5 10.5 1.5 11.5 ns
2.5 11.5 2.0 12.5 ns
2.0 11.5 2.0 12.5 ns
Typical @25°C,VCC=5.0 V
Unit
Figure 1. Switching Waveforms Figure 2. Switching Waveforms
Figure 3. Switching Waveforms
161
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IN74ACT138
EXPANDED LOGIC DIAGRAM
162
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