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Part Number HD74HC137

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HD74HC137
3-to-8-line Decoder/Demultiplexer with Address Latch
Description
The HD74HC137 implements a three-to-eight line decoder with latches on the three address inputs. When
GL goes from low to high, the address present at the select inputs (A, B and C) is stored in the latches. As
long as
GL remains high no address changes will be recognized. Output enable controls, G
1
and G
2
, control
the state of the outputs independently of the select or latch-enable inputs.
All of the outputs are high unless G
1
is high and G
2
is low. The HD74HC137 is ideally suited for the
implementation of glitchfree decoders in stored-address applications in bus oriented systems.
Features
·
High Speed Operation: t
pd
(A, B, C to Y) = 16.5 ns typ (C
L
= 50 pF)
·
High Output Current: Fanout of 10 LSTTL Loads
·
Wide Operating Voltage: V
CC
= 2 V to 6 V
·
Low Input Current: 1 µA max
·
Low Quiescent Supply Current: I
CC
(static) = 4 µA max (Ta = 25°C)
HD74HC137
2
Function Table
Inputs
Enable
Select
Outputs
GL
G
1
G
2
C
B
A
Y
0
Y
1
Y
2
Y
3
Y
4
Y
5
Y
6
Y
7
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
Pin Arrangement
1
2
3
4
5
6
7
8
A
B
C
GL
G
2
G
1
Y
7
GND
V
CC
Y
0
Y
1
Y
2
Y
3
Y
4
Y
5
Y
6
16
15
14
13
12
11
10
9
(Top view)
B
C
GL
G
2
G
1
Y
7
Y
1
Y
0
A
Y
6
Y
2
Y
3
Y
4
Y
5
HD74HC137
3
Block Diagram
Y
7
G
1
GL
A
G
2
Y
6
Y
5
Y
4
Y
3
Y
2
Y
1
Y
0
B
C
HD74HC137
4
DC Characteristics
Ta = 25
°
C
Ta = ­40 to
+85
°
C
Item
Symbol
V
CC
(V) Min Typ Max Min
Max
Unit
Test Conditions
Input voltage
V
IH
2.0
1.5
--
--
1.5
--
V
4.5
3.15 --
--
3.15
--
6.0
4.2
--
--
4.2
--
V
IL
2.0
--
--
0.5
--
0.5
V
4.5
--
--
1.35 --
1.35
6.0
--
--
1.8
--
1.8
Output voltage
V
OH
2.0
1.9
2.0
--
1.9
--
V
Vin = V
IH
or V
IL
I
OH
= ­20
µ
A
4.5
4.4
4.5
--
4.4
--
6.0
5.9
6.0
--
5.9
--
4.5
4.18 --
--
4.13
--
I
OH
= ­4 mA
6.0
5.68 --
--
5.63
--
I
OH
= ­5.2 mA
V
OL
2.0
--
0.0
0.1
--
0.1
V
Vin = V
IH
or V
IL
I
OL
= 20
µ
A
4.5
--
0.0
0.1
--
0.1
6.0
--
0.0
0.1
--
0.1
4.5
--
--
0.26 --
0.33
I
OL
= 4 mA
6.0
--
--
0.26 --
0.33
I
OL
= 5.2 mA
Input current
Iin
6.0
--
--
±
0.1 --
±
1.0
µ
A
Vin = V
CC
or GND
Quiescent supply
current
I
CC
6.0
--
--
4.0
--
40
µ
A
Vin = V
CC
or GND, Iout = 0
µ
A
HD74HC137
5
AC Characteristics (C
L
= 50 pF, Input t
r
= t
f
= 6 ns)
Ta = 25
°
C
Ta = ­40 to
+85
°
C
Item
Symbol
V
CC
(V) Min Typ Max Min
Max
Unit
Test Conditions
Propagation delay t
PLH
2.0
--
--
170 --
215
ns
A, B or C to Y
time
4.5
--
16
34
--
43
6.0
--
--
29
--
37
t
PHL
2.0
--
--
240 --
300
ns
4.5
--
17
48
--
60
6.0
--
--
41
--
51
t
PLH
2.0
--
--
130 --
165
ns
G
2
to Y
4.5
--
13
26
--
33
6.0
--
--
22
--
28
t
PHL
2.0
--
--
195 --
245
ns
4.5
--
14
39
--
49
6.0
--
--
33
--
42
t
PLH
2.0
--
--
150 --
190
ns
G
1
to Y
4.5
--
14
30
--
38
6.0
--
--
26
--
33
t
PHL
2.0
--
--
195 --
245
ns
4.5
--
14
39
--
49
6.0
--
--
33
--
42
t
PLH
2.0
--
--
175 --
220
ns
GL
to Y
4.5
--
17
35
--
44
6.0
--
--
30
--
37
t
PHL
2.0
--
--
250 --
315
ns
4.5
--
18
50
--
63
6.0
--
--
43
--
54
Setup time
t
su
2.0
100 --
--
125
--
ns
A, B, C inputs
4.5
20
3
--
25
--
6.0
17
--
--
21
--
Hold time
t
h
2.0
50
--
--
65
--
ns
A, B, C inputs
4.5
10
­3
--
13
--
6.0
9
--
--
11
--