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Электронный компонент: HD74HC42

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HD74HC42
BCD-to-Decimal Decoder
Description
Data on the four input pins select one of the 10 outputs corresponding to the value of the BCD number on
the inputs. An output will go low when selected, otherwise it remains high. If the input data is not a valid
BCD number all outputs will remain high.
Features
High Speed Operation: t
pd
= 13 ns typ (C
L
= 50 pF)
High Output Current: Fanout of 10 LSTTL Loads
Wide Operating Voltage: V
CC
= 2 to 6 V
Low Input Current: 1 A max
Low Quiescent Supply Current: I
CC
(static) = 4 A max (Ta = 25C)
HD74HC42
2
Function Table
BCD Inputs
Decimal Outputs
No.
D
C
B
A
0
1
2
3
4
5
6
7
8
9
0
L
L
L
L
L
H
H
H
H
H
H
H
H
H
1
L
L
L
H
H
L
H
H
H
H
H
H
H
H
2
L
L
H
L
H
H
L
H
H
H
H
H
H
H
3
L
L
H
H
H
H
H
L
H
H
H
H
H
H
4
L
H
L
L
H
H
H
H
L
H
H
H
H
H
5
L
H
L
H
H
H
H
H
H
L
H
H
H
H
6
L
H
H
L
H
H
H
H
H
H
L
H
H
H
7
L
H
H
H
H
H
H
H
H
H
H
L
H
H
8
H
L
L
L
H
H
H
H
H
H
H
H
L
H
9
H
L
L
H
H
H
H
H
H
H
H
H
H
L
INVALID
H
L
H
L
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Pin Arrangement
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
9
A
B
C
D
(Top view)
Outputs
Outputs
Inputs
0Y
1Y
2Y
3Y
4Y
5Y
6Y
GND
16
15
14
13
12
11
10
9
V
CC
A
B
C
D
9Y
8Y
7Y
HD74HC42
3
Logic Diagram
A
0Y
1Y
2Y
3Y
4Y
5Y
6Y
7Y
8Y
9Y
B
C
D
HD74HC42
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
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
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
A
Vin = V
CC
or GND
Quiescent supply
current
I
CC
6.0
--
--
4.0
--
40
A
Vin = V
CC
or GND, Iout = 0
A
HD74HC42
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
--
--
150 --
190
ns
time
4.5
--
13
30
--
38
6.0
--
--
26
--
33
t
PHL
2.0
--
--
150 --
190
ns
4.5
--
13
30
--
38
6.0
--
--
26
--
33
Output rise/fall
t
TLH
2.0
--
--
75
--
95
ns
time
t
THL
4.5
--
5
15
--
19
6.0
--
--
13
--
16
Input capacitance
Cin
--
--
5
10
--
10
pF