SN54ALS137A, SN74ALS137A, SN74AS137
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
WITH ADDRESS LATCHES
SDAS203C APRIL 1982 REVISED JANUARY 1995
Copyright
1995, Texas Instruments Incorporated
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Combines Decoder and 3-Bit Address
Latch
Incorporates Two Output Enables to
Simplify Cascading
Package Options Include Plastic Small-
Outline (D) Packages, Ceramic Chip
Carriers (FK), and Standard Plastic (N) and
Ceramic (J) 300-mil DIPs
description
The SN54ALS137A, SN74ALS137A, and
SN74AS137 are 3-line to 8-line decoders/
demultiplexers with latches on the three address
inputs. When the latch-enable (LE) input is low,
the devices act as decoders/demultiplexers.
When LE goes from low to high, the address
present at the select (A, B, and C) inputs is stored
in the latches. Further address changes are
ignored as long as LE remains high. The
output-enable controls (G1 and G2) control the
outputs independently of the select or
latch-enable inputs. All of the outputs are forced
high if G1 is low or G2 is high. These devices are
ideally suited for implementing glitch-free
decoders in strobed (stored-address) applications
in bus-oriented systems.
The SN54ALS137A is characterized for operation
over the full military temperature range of 55
C
to 125
C. The SN74ALS137A and SN74AS137
are characterized for operation from 0
C to 70
C.
FUNCTION TABLE
INPUTS
OUTPUTS
ENABLE
SELECT
OUTPUTS
LE
G1
G2
C
B
A
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
X
H
X
X
X
H
H
H
H
H
H
H
H
X
L
X
X
X
X
H
H
H
H
H
H
H
H
L
H
L
L
L
L
L
H
H
H
H
H
H
H
L
H
L
L
L
H
H
L
H
H
H
H
H
H
L
H
L
L
H
L
H
H
L
H
H
H
H
H
L
H
L
L
H
H
H
H
H
L
H
H
H
H
L
H
L
H
L
L
H
H
H
H
L
H
H
H
L
H
L
H
L
H
H
H
H
H
H
L
H
H
L
H
L
H
H
L
H
H
H
H
H
H
L
H
L
H
L
H
H
H
H
H
H
H
H
H
H
L
H
H
L
X
X
X
Outputs corresponding to stored address = L; all others = H
SN54ALS137A . . . J PACKAGE
SN74ALS137A, SN74AS137 . . . D OR N PACKAGE
(TOP VIEW)
3
2
1 20 19
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
Y1
Y2
NC
Y3
Y4
C
LE
NC
G2
G1
SN54ALS137A . . . FK PACKAGE
(TOP VIEW)
B
A
NC
Y6
Y5
Y0
Y7
GND
NC
NC No internal connection
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
A
B
C
LE
G2
G1
Y7
GND
V
CC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
SN54ALS137A, SN74ALS137A, SN74AS137
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
WITH ADDRESS LATCHES
SDAS203C APRIL 1982 REVISED JANUARY 1995
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
logic symbols (alternatives)
X/Y
1
A
2
B
3
C
C8
4
5
6
G1
Y0
15
0
&
EN
Y1
14
1
Y2
13
2
Y3
12
3
Y4
11
4
Y5
10
5
Y6
9
6
Y7
7
7
G
7
0
LE
G2
8D
1
2
4
DMUX
1
A
2
B
3
C
C8
4
5
6
G1
Y0
15
0
&
Y1
14
1
Y2
13
2
Y3
12
3
Y4
11
4
Y5
10
5
Y6
9
6
Y7
7
7
LE
G2
8D
0
2
These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, and N packages.
logic diagram (positive logic)
G1
G2
LE
C
B
A
6
5
4
3
2
1
Output
Enables
Latch
Enable
Select
Inputs
Data
Outputs
Y7
Y6
Y5
Y4
Y3
Y2
Y1
Y0
10
11
12
13
14
7
9
15
Pin numbers shown are for the D, J, and N packages.
SN54ALS137A, SN74ALS137A, SN74AS137
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
WITH ADDRESS LATCHES
SDAS203C APRIL 1982 REVISED JANUARY 1995
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
CC
7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, V
I
7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
: SN54ALS137A
55
C to 125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74ALS137A
0
C to 70
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
recommended operating conditions
SN54ALS137A
SN74ALS137A
UNIT
MIN
NOM
MAX
MIN
NOM
MAX
UNIT
VCC
Supply voltage
4.5
5
5.5
4.5
5
5.5
V
VIH
High-level input voltage
2
2
V
VIL
Low-level input voltage
0.7
0.8
V
IOH
High-level output current
0.4
0.4
mA
IOL
Low-level output current
4
8
mA
tw
Pulse duration, LE low
15
10
ns
tsu
Setup time at A, B, and C before LE
15
10
ns
th
Hold time at A, B, and C after LE
5
5
ns
TA
Operating free-air temperature
55
125
0
70
C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
SN54ALS137A
SN74ALS137A
UNIT
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNIT
VIK
VCC = 4.5 V,
II = 18 mA
1.5
1.5
V
VOH
VCC = 4.5 V to 5.5 V,
IOH = 0.4 mA
VCC 2
VCC 2
V
VOL
VCC = 4 5 V
IOL = 4 mA
0.25
0.4
0.25
0.4
V
VOL
VCC = 4.5 V
IOL = 8 mA
0.35
0.5
V
II
VCC = 5.5 V,
VI = 7 V
0.1
0.1
mA
IIH
VCC = 5.5 V,
VI = 2.7 V
20
20
A
IIL
VCC = 5.5 V,
VI = 0.4 V
0.1
0.1
mA
IO
VCC = 5.5 V,
VO = 2.25 V
20
112
30
112
mA
ICC
VCC = 5.5 V
5
11
5
11
mA
All typical values are at VCC = 5 V, TA = 25
C.
The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.
SN54ALS137A, SN74ALS137A, SN74AS137
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
WITH ADDRESS LATCHES
SDAS203C APRIL 1982 REVISED JANUARY 1995
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 500
,
TA = MIN to MAX
UNIT
(INPUT)
(OUTPUT)
SN54ALS137A
SN74ALS137A
MIN
MAX
MIN
MAX
tPLH
A B C
Y
5
25
5
20
ns
tPHL
A, B, C
Y
6
25
6
20
ns
tPLH
G2
Y
4
15
3
12
ns
tPHL
G2
Y
5
18
4
15
ns
tPLH
G1
Y
5
21
4
17
ns
tPHL
G1
Y
5
19
4
15
ns
tPLH
LE
Y
7
27
6
22
ns
tPHL
LE
Y
7
25
7
20
ns
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
CC
7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, V
I
7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
: SN74AS137
0
C to 70
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
recommended operating conditions
SN74AS137
UNIT
MIN
NOM
MAX
UNIT
VCC
Supply voltage
4.5
5
5.5
V
VIH
High-level input voltage
2
V
VIL
Low-level input voltage
0.8
V
IOH
High-level output current
2
mA
IOL
Low-level output current
20
mA
tw
Pulse duration, LE low
6.5
ns
tsu
Setup time at A, B, and C before LE
4
ns
th
Hold time at A, B, and C after LE
1
ns
TA
Operating free-air temperature
0
70
C
SN54ALS137A, SN74ALS137A, SN74AS137
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
WITH ADDRESS LATCHES
SDAS203C APRIL 1982 REVISED JANUARY 1995
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
SN74AS137
UNIT
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VIK
VCC = 4.5 V,
II = 18 mA
1.2
V
VOH
VCC = 4.5 V to 5.5 V,
IOH = 2 mA
VCC 2
V
VOL
VCC = 4.5 V,
IOL = 20 mA
0.35
0.5
V
II
VCC = 5.5 V,
VI = 7 V
0.1
mA
IIH
VCC = 5.5 V,
VI = 2.7 V
20
A
IIL
VCC = 5.5 V,
VI = 0.4 V
1
mA
IO
VCC = 5.5 V,
VO = 2.25 V
30
112
mA
ICC
VCC = 5.5 V
15
24
mA
All typical values are at VCC = 5 V, TA = 25
C.
The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 500
,
TA = MIN to MAX
UNIT
(INPUT)
(OUTPUT)
SN74AS137
MIN
MAX
tPLH
A B C
Y
2
12.5
ns
tPHL
A, B, C
Y
2
12.5
ns
tPLH
G2
Y
2
8
ns
tPHL
G2
Y
2
8.5
ns
tPLH
G1
Y
2
10
ns
tPHL
G1
Y
2
9
ns
tPLH
LE
Y
3
13.5
ns
tPHL
LE
Y
3
14
ns
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
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