NSC 54LS138J

54LS138/DM54LS138/DM74LS138,
54LS139/DM54LS139/DM74LS139
Decoders/Demultiplexers
General Description
These Schottky-clamped circuits are designed to be used in
high-performance memory-decoding or data-routing applications, requiring very short propagation delay times. In
high-performance memory systems these decoders can be
used to minimize the effects of system decoding. When
used with high-speed memories, the delay times of these
decoders are usually less than the typical access time of the
memory. This means that the effective system delay introduced by the decoder is negligible.
The LS138 decodes one-of-eight lines, based upon the conditions at the three binary select inputs and the three enable
inputs. Two active-low and one active-high enable inputs
reduce the need for external gates or inverters when expanding. A 24-line decoder can be implemented with no external inverters, and a 32-line decoder requires only one
inverter. An enable input can be used as a data input for
demultiplexing applications.
The LS139 comprises two separate two-line-to-four-line decoders in a single package. The active-low enable input can
be used as a data line in demultiplexing applications.
All of these decoders/demultiplexers feature fully buffered
inputs, presenting only one normalized load to its driving
circuit. All inputs are clamped with high-performance
Schottky diodes to suppress line-ringing and simplify system
design.
Features
Y
Y
Y
Y
Y
Y
Y
Designed specifically for high speed:
Memory decoders
Data transmission systems
LS138 3-to-8-line decoders incorporates 3 enable inputs to simplify cascading and/or data reception
LS139 contains two fully independent 2-to-4-line decoders/demultiplexers
Schottky clamped for high performance
Typical propagation delay (3 levels of logic)
LS138 21 ns
LS139 21 ns
Typical power dissipation
LS138 32 mW
LS139 34 mW
Alternate
Military/Aerospace
devices
(54LS138,
54LS139) are available. Contact a National Semiconductor Sales Office/Distributor for specifications.
Connection Diagrams
Dual-in-Line Package
Dual-in-Line Package
TL/F/6391 – 1
Order Number 54LS138DMQB, 54LS138FMQB,
54LS138LMQB, DM54LS138J, DM54LS138W,
DM74LS138M or DM74LS138N
See NS Package Number E20A, J16A,
M16A, N16E or W16A
C1995 National Semiconductor Corporation
TL/F/6391
TL/F/6391 – 2
Order Number 54LS139DMQB, 54LS139FMQB,
54LS139LMQB, DM54LS139J, DM54LS139W,
DM74LS139M or DM74LS139N
See NS Package Number E20A, J16A,
M16A, N16E or W16A
RRD-B30M105/Printed in U. S. A.
54LS138/DM54LS138/DM74LS138,
54LS139/DM54LS139/DM74LS139 Decoders/Demultiplexers
June 1989
Absolute Maximum Ratings (Note)
Note: 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’’
table are not guaranteed at the absolute maximum ratings.
The ‘‘Recommended Operating Conditions’’ table will define
the conditions for actual device operation.
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range
b 55§ C to a 125§ C
DM54LS and 54LS
DM74LS
0§ C to a 70§ C
Storage Temperature Range
b 65§ C to a 150§ C
Recommended Operating Conditions
Symbol
DM54LS138
Parameter
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IOH
High Level Output Current
IOL
Low Level Output Current
TA
Free Air Operating Temperature
DM74LS138
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.25
2
2
V
0.7
0.8
V
b 0.4
b 0.4
mA
4
b 55
V
125
0
8
mA
70
§C
Max
Units
b 1.5
V
’LS138 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
(Note 1)
VI
Input Clamp Voltage
VCC e Min, II e b18 mA
VOH
High Level Output
Voltage
VCC e Min, IOH e Max,
VIL e Max, VIH e Min
DM54
2.5
3.4
DM74
2.7
3.4
Low Level Output
Voltage
VCC e Min, IOL e Max,
VIL e Max, VIH e Min
DM54
0.25
0.4
DM74
0.35
0.5
IOL e 4 mA, VCC e Min
DM74
0.25
0.4
VOL
V
V
II
Input Current @ Max
Input Voltage
VCC e Max, VI e 7V
IIH
High Level Input Current
VCC e Max, VI e 2.7V
20
mA
IIL
Low Level Input Current
VCC e Max, VI e 0.4V
b 0.36
mA
IOS
Short Circuit
Output Current
VCC e Max
(Note 2)
Supply Current
VCC e Max (Note 3)
ICC
0.1
DM54
b 20
b 100
DM74
b 20
b 100
Note 1: All typicals are at VCC e 5V, TA e 25§ C.
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 3: ICC is measured with all outputs enabled and open.
2
6.3
10
mA
mA
mA
’LS138 Switching Characteristics
at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load)
Symbol
Parameter
From (Input)
To (Output)
RL e 2 kX
Levels
of Delay
CL e 15 pF
Min
Max
CL e 50 pF
Min
Units
Max
tPLH
Propagation Delay Time
Low to High Level Output
Select to
Output
2
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Select to
Output
2
27
40
ns
tPLH
Propagation Delay Time
Low to High Level Output
Select to
Output
3
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Select to
Output
3
27
40
ns
tPLH
Propagation Delay Time
Low to High Level Output
Enable to
Output
2
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Enable to
Output
2
24
40
ns
tPLH
Propagation Delay Time
Low to High Level Output
Enable to
Output
3
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Enable to
Output
3
28
40
ns
Recommended Operating Conditions
Symbol
DM54LS139
Parameter
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IOH
High Level Output Current
IOL
Low Level Output Current
TA
Free Air Operating Temperature
DM74LS139
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.25
V
0.7
0.8
V
b 0.4
b 0.4
mA
8
mA
70
§C
2
2
4
b 55
125
3
0
V
’LS139 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
(Note 1)
Max
Units
b 1.5
V
VI
Input Clamp Voltage
VCC e Min, II e b18 mA
VOH
High Level Output
Voltage
VCC e Min, IOH e Max,
VIL e Max, VIH e Min
DM54
2.5
3.4
DM74
2.7
3.4
Low Level Output
Voltage
VCC e Min, IOL e Max
VIL e Max, VIH e Min
DM54
0.25
0.4
DM74
0.35
0.5
IOL e 4 mA, VCC e Min
DM74
0.25
0.4
VOL
V
V
II
Input Current @ Max
Input Voltage
VCC e Max, VI e 7V
IIH
High Level Input Current
VCC e Max, VI e 2.7V
20
mA
IIL
Low Level Input Current
VCC e Max, VI e 0.4V
b 0.36
mA
IOS
Short Circuit
Output Current
VCC e Max
(Note 2)
Supply Current
VCC e Max (Note 3)
ICC
0.1
DM54
b 20
b 100
DM74
b 20
b 100
6.8
11
mA
mA
mA
Note 1: All typicals are at VCC e 5V, TA e 25§ C.
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 3: ICC is measured with all outputs enabled and open.
’LS139 Switching Characteristics
at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load)
Symbol
From (Input)
To (Output)
Parameter
RL e 2 kX
CL e 15 pF
Min
CL e 50 pF
Max
Min
Units
Max
tPLH
Propagation Delay Time
Low to High Level Output
Select to
Output
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Select to
Output
27
40
ns
tPLH
Propagation Delay Time
Low to High Level Output
Enable to
Output
18
27
ns
tPHL
Propagation Delay Time
High to Low Level Output
Enable to
Output
24
40
ns
Function Tables
LS138
Inputs
Enable
LS139
Inputs
Outputs
Select
Enable
Outputs
Select
G1 G2* C B A YO Y1 Y2 Y3 Y4 Y5 Y6 Y7
G
B
A
Y0
Y1
Y2
Y3
X
L
H
H
H
H
H
H
H
H
H
L
L
L
L
X
L
L
H
H
X
L
H
L
H
H
L
H
H
H
H
H
L
H
H
H
H
H
L
H
H
H
H
H
L
H
X
L
L
L
L
L
L
L
L
X
X
L
L
L
L
H
H
H
H
X
X
L
L
H
H
L
L
H
H
X
X
L
H
L
H
L
H
L
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
L
H e High Level, L e Low Level, X e Don’t Care
* G2 e G2A a G2B
H e High Level, L e Low Level, X e Don’t Care
4
Logic Diagrams
LS138
TL/F/6391 – 3
LS139
TL/F/6391 – 4
5
Physical Dimensions inches (millimeters)
Ceramic Leadless Chip Carrier Package (E)
Order Number 54LS138LMQB or 54LS139LMQB
NS Package Number E20A
16-Lead Ceramic Dual-In-Line Package (J)
Order Number 54LS138DMQB, 54LS139DMQB, DM54LS138J or DM54LS139J
NS Package Number J16A
6
Physical Dimensions inches (millimeters) (Continued)
16-Lead Small Outline Molded Package (M)
Order Number DM74LS138M or DM74LS139M
NS Packge Number M16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DM74LS138N or DM74LS139N
NS Package Number N16E
7
54LS138/DM54LS138/DM74LS138,
54LS139/DM54LS139/DM74LS139 Decoders/Demultiplexers
Physical Dimensions inches (millimeters) (Continued)
16-Lead Ceramic Flat Package (W)
Order Number 54LS138FMQB, 54LS139FMQB, DM54LS138W or DM54LS139W
NS Package Number W16A
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