54LS138W [NSC]
Decoders/Demultiplexers; 解码器/多路解复用器
| 型号： | 54LS138W |
| 厂家： | 
National Semiconductor |
| 描述： | Decoders/Demultiplexers |
| 文件： | 总8页 (文件大小：167K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
June 1989
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 appli-
cations, 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 intro-
duced by the decoder is negligible.
Schottky diodes to suppress line-ringing and simplify system
design.
Features
Y
Designed specifically for high speed:
Memory decoders
Data transmission systems
Y
LS138 3-to-8-line decoders incorporates 3 enable in-
puts to simplify cascading and/or data reception
The LS138 decodes one-of-eight lines, based upon the con-
ditions 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 ex-
panding. A 24-line decoder can be implemented with no ex-
ternal inverters, and a 32-line decoder requires only one
inverter. An enable input can be used as a data input for
demultiplexing applications.
Y
LS139 contains two fully independent 2-to-4-line decod-
ers/demultiplexers
Y
Schottky clamped for high performance
Y
Typical propagation delay (3 levels of logic)
LS138 21 ns
LS139 21 ns
Y
Typical power dissipation
LS138 32 mW
LS139 34 mW
The LS139 comprises two separate two-line-to-four-line de-
coders in a single package. The active-low enable input can
be used as a data line in demultiplexing applications.
Y
Alternate
Military/Aerospace
devices
(54LS138,
54LS139) are available. Contact a National Semicon-
ductor Sales Office/Distributor for specifications.
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
Connection Diagrams
Dual-in-Line Package
Dual-in-Line Package
TL/F/6391–1
Order Number 54LS138DMQB, 54LS138FMQB,
54LS138LMQB, DM54LS138J, DM54LS138W,
DM74LS138M or DM74LS138N
TL/F/6391–2
Order Number 54LS139DMQB, 54LS139FMQB,
54LS139LMQB, DM54LS139J, DM54LS139W,
DM74LS139M or DM74LS139N
See NS Package Number E20A, J16A,
M16A, N16E or W16A
See NS Package Number E20A, J16A,
M16A, N16E or W16A
C
1995 National Semiconductor Corporation
TL/F/6391
RRD-B30M105/Printed in U. S. A.
Absolute Maximum Ratings (Note)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaran-
teed. 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.
Supply Voltage
Input Voltage
7V
7V
Operating Free Air Temperature Range
DM54LS and 54LS
DM74LS
b
b
a
a
55 C to 125 C
§
§
0 C to 70 C
§
§
a
65 C to 150 C
Storage Temperature Range
§
§
Recommended Operating Conditions
DM54LS138
DM74LS138
Symbol
Parameter
Units
Min
4.5
2
Nom
Max
Min
4.75
2
Nom
Max
V
V
V
Supply Voltage
5
5.5
5
5.25
V
V
CC
High Level Input Voltage
Low Level Input Voltage
High Level Output Current
Low Level Output Current
Free Air Operating Temperature
IH
0.7
0.8
V
IL
b
b
0.4
I
I
0.4
mA
mA
OH
OL
4
8
b
T
A
55
125
0
70
C
§
’LS138 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Typ
Symbol
Parameter
Conditions
Min
Max
Units
(Note 1)
e
e
e b
e
b
1.5
V
V
Input Clamp Voltage
V
Min, I
Min, I
18 mA
V
V
I
CC
I
High Level Output
Voltage
V
V
Max,
Min
DM54
DM74
DM54
DM74
DM74
2.5
2.7
3.4
3.4
OH
CC
OH
e
e
Max, V
IL
IH
e
e
e
V
OL
Low Level Output
Voltage
V
V
Min, I
Max,
Min
0.25
0.35
0.25
0.4
CC
OL
e
Max, V
IH
IL
0.5
0.4
V
e
e
I
4 mA, V
CC
Min
OL
@
Input Current Max
e
e
I
V
Max, V
7V
I
CC
I
0.1
20
mA
Input Voltage
e
e
e
e
e
I
I
I
High Level Input Current
Low Level Input Current
V
CC
V
CC
V
CC
Max, V
Max, V
Max
2.7V
0.4V
mA
IH
IL
I
b
0.36
mA
I
b
b
Short Circuit
DM54
DM74
20
20
100
100
OS
mA
mA
Output Current
(Note 2)
b
b
e
CC
I
Supply Current
V
Max (Note 3)
6.3
10
CC
e
e
25 C.
Note 1: All typicals are at V
5V, T
§
CC
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 3: I is measured with all outputs enabled and open.
A
CC
2
’LS138 Switching Characteristics
5V and T
e
e
at V
25 C (See Section 1 for Test Waveforms and Output Load)
§
CC
A
e
R
2 kX
L
From (Input)
To (Output)
Levels
e
e
L
Symbol
Parameter
C
L
15 pF
C
50 pF
Max
Units
of Delay
Min
Max
Min
t
t
t
t
t
t
t
t
Propagation Delay Time
Low to High Level Output
Select to
Output
PLH
PHL
PLH
PHL
PLH
PHL
PLH
PHL
2
2
3
3
2
2
3
3
18
27
40
27
40
27
40
27
40
ns
ns
ns
ns
ns
ns
ns
ns
Propagation Delay Time
High to Low Level Output
Select to
Output
27
18
27
18
24
18
28
Propagation Delay Time
Low to High Level Output
Select to
Output
Propagation Delay Time
High to Low Level Output
Select to
Output
Propagation Delay Time
Low to High Level Output
Enable to
Output
Propagation Delay Time
High to Low Level Output
Enable to
Output
Propagation Delay Time
Low to High Level Output
Enable to
Output
Propagation Delay Time
High to Low Level Output
Enable to
Output
Recommended Operating Conditions
DM54LS139
DM74LS139
Symbol
Parameter
Units
Min
4.5
2
Nom
Max
Min
Nom
Max
V
V
V
Supply Voltage
5
5.5
4.75
2
5
5.25
V
V
CC
High Level Input Voltage
Low Level Input Voltage
High Level Output Current
Low Level Output Current
Free Air Operating Temperature
IH
0.7
0.8
V
IL
b
b
0.4
I
I
0.4
mA
mA
OH
OL
4
8
b
T
A
55
125
0
70
C
§
3
’LS139 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Typ
Symbol
Parameter
Conditions
Min
Max
Units
(Note 1)
e
e
e b
e
b
1.5
V
V
Input Clamp Voltage
V
Min, I
Min, I
18 mA
V
V
I
CC
I
High Level Output
Voltage
V
V
Max,
Min
DM54
DM74
DM54
DM74
DM74
2.5
2.7
3.4
3.4
OH
CC
OH
e
e
Max, V
IL
IH
e
e
e
V
OL
Low Level Output
Voltage
V
V
Min, I
Max
Min
0.25
0.35
0.25
0.4
CC
OL
e
Max, V
IH
IL
0.5
0.4
V
e
e
I
4 mA, V
CC
Min
OL
@
Input Current Max
e
e
I
V
Max, V
7V
I
CC
I
0.1
20
mA
Input Voltage
e
e
e
e
e
I
I
I
High Level Input Current
Low Level Input Current
V
CC
V
CC
V
CC
Max, V
Max, V
Max
2.7V
0.4V
mA
IH
IL
I
b
0.36
mA
I
b
b
b
Short Circuit
DM54
DM74
20
20
100
100
OS
mA
mA
Output Current
(Note 2)
b
e
CC
I
Supply Current
V
Max (Note 3)
6.8
11
CC
e
e
25 C.
Note 1: All typicals are at V
5V, T
§
CC
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 3: I is measured with all outputs enabled and open.
A
CC
’LS139 Switching Characteristics
5V and T
e
e
A
at V
25 C (See Section 1 for Test Waveforms and Output Load)
§
CC
e
R
L
2 kX
From (Input)
e
e
L
Symbol
Parameter
C
15 pF
C
50 pF
Max
Units
To (Output)
L
Min
Max
Min
t
t
t
t
Propagation Delay Time
Low to High Level Output
Select to
Output
PLH
PHL
PLH
PHL
18
27
40
27
40
ns
ns
ns
ns
Propagation Delay Time
High to Low Level Output
Select to
Output
27
18
24
Propagation Delay Time
Low to High Level Output
Enable to
Output
Propagation Delay Time
High to Low Level Output
Enable to
Output
Function Tables
LS138
LS139
Y0
Inputs
Enable Select
G1 G2*
Inputs
Select
Outputs
Outputs
Enable
G
C
B
A
YO Y1 Y2 Y3 Y4 Y5 Y6 Y7
B
A
Y1
Y2
Y3
X
L
H
X
L
L
L
L
L
L
L
L
X
X
L
X
X
L
X
X
L
H
H
L
H
H
H
L
H
H
H
H
L
H
H
H
H
H
L
H
H
H
H
H
H
L
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
H
L
H
L
L
L
L
X
L
X
L
H
L
H
H
L
H
H
H
L
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
L
H
H
H
L
L
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
L
H
H
H
H
H
H
H
H
L
H
L
H
H
H
H
H
e
e
e
Low Level, X Don’t Care
H
High Level, L
H
H
H
H
H
H
H
H
L
H
L
H
H
H
H
H
H
H
H
H
e
a
G2B
* G2
G2A
e
e
e
H
High Level, L
Low Level, X
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
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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with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life
support device or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
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