© 2000 Fairchild Semiconductor Corporation
DS006202
www.fairchildsemi.com
February 1991
Revised February 2000
DM74ALS137 3 to 8
Li
ne Decoder/
D
emult
i
pl
exer wit
h
Addr
ess Latche
s
DM74ALS137
3 to 8 Line Decoder/Demultiplexer with Address Latches
General Description
The ALS137 is a three line to eight line decoder/demulti-
plexer with latches on the three address inputs. When the
latch-enable input (GL) is LOW, the ALS137 acts as a
decoder/demultiplexer. When GL goes from LOW-to-HIGH,
the address present at the select inputs (A, B, and C) is
stored in the latches. Further address changes are ignored
as long as GL remains HIGH. The output enable controls,
G1 and G2, control the state of the outputs independently
of the select or latch-enable inputs. All of the outputs are
HIGH unless G1 is HIGH and G2 is LOW. The ALS137 is
ideally suited for implementing glitch-free decoders in
strobed (stored-address) applications in bus-oriented sys-
tems.
Features
s
Combines decoder and 3-bit address latch
s
Incorporates 3 enable inputs to simplify cascading
s
Low power dissipation:
28 mW typ
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code.
Connection Diagram
Function Table
L
=
LOW State
H
=
HIGH State
X
=
Don't Care
Order Number
Package Number
Package Description
DM74ALS137M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74ALS137N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Inputs
Outputs
Enable
Select
GL 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
Output corresponding to stored
address, L; all others, H
3
www.fairchildsemi.com
DM74ALS137
Absolute Maximum Ratings
(Note 1)
Note 1: 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 tables are not guaranteed at the absolute maximum ratings.
The "Recommended Operating Conditions" table will define the conditions
for actual device operation.
Recommended Operating Conditions
Note 2: The arrow (
) indicates the positive edge of the GL input pulse is used for reference.
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25
°
C.
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range
0
°
C to
+
70
°
C
Storage Temperature Range
-
65
°
C to
+
150
°
C
Typical
JA
N Package
75.5
°
C/W
M Package
104.0
°
C/W
Symbol
Parameter
Min
Nom
Max
Units
V
CC
Supply Voltage
4.5
5
5.5
V
V
IH
HIGH Level Input Voltage
2
V
V
IL
LOW Level Input Voltage
0.8
V
I
OH
HIGH Level Output Current
-
0.4
mA
I
OL
LOW Level Output Current
8
mA
t
W
Width of Enabling Pulse
GL LOW
10
ns
t
SU
Setup Time (Note 2)
A, B, C
10
ns
t
H
Hold Time (Note 2)
A, B, C
5
ns
T
A
Free Air Operating Temperature
0
70
°
C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
IK
Input Clamp Voltage
V
CC
=
4.5V, I
I
=
-
18 mA
-
1.5
V
V
OH
HIGH Level
I
OH
=
-
0.4 mA
V
CC
-
2
V
Output Voltage
V
CC
=
4.5V to 5.5V
V
OL
LOW
Level V
CC
=
4.5V
I
OL
=
4 mA
0.25
0.4
V
Output Voltage
I
OL
=
8 mA
0.35
0.5
V
I
I
Input Current @ Maximum
V
CC
=
5.5V
Enable
0.1
mA
Input Voltage
V
IH
=
7V
A, B, C
0.1
I
IH
HIGH Level
V
CC
=
5.5V
Enable
20
µ
A
Input Current
V
IH
=
2.7V
A, B, C
20
I
IL
LOW
Level V
CC
=
5.5V
Enable
-
0.1
mA
Input Current
V
IL
=
0.4V
A, B, C
-
0.1
I
O
Output Drive Current
V
CC
=
5.5V, V
O
=
2.25V
-
30
-
112
mA
I
CC
Supply Current
V
CC
=
5.5V
5
11
mA
5
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DM74ALS137
Physical Dimensions
inches (millimeters) unless otherwise noted
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
Package Number M16A
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