HITACHI HD74HCT238

HD74HCT238
3-to-8-line Decoder/Demultiplexer
Description
The HD74HCT238 has 3 binary select inputs (A, B, and C). If the device is enabled these inputs
determined which one of the eight normally high outputs will go low. Two active low and one active high
enables (G1, G2A and G2B) are provided to ease the cascading of decoders.
Features
•
•
•
•
•
•
LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility
High Speed Operation: tpd (A, B, C to Y) = 18.5 ns typ (CL = 50 pF)
High Output Current: Fanout of 10 LSTTL Loads
Wide Operating Voltage: VCC = 4.5 to 5.5 V
Low Input Current: 1 µA max
Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
HD74HCT238
Function Table
Inputs
Enable
Select
Outputs
G1
G2A
G2B
C
B
A
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
X
H
X
X
X
L
L
L
L
L
L
L
L
X
H
X
X
X
X
L
L
L
L
L
L
L
L
L
X
X
X
X
X
L
L
L
L
L
L
L
L
H
L
L
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
L
H
L
H
L
L
L
L
L
L
H
L
L
L
H
L
L
L
H
L
L
L
L
L
H
L
L
L
H
H
L
L
L
H
L
L
L
L
H
L
L
H
L
L
L
L
L
L
H
L
L
L
H
L
L
H
L
H
L
L
L
L
L
H
L
L
H
L
L
H
H
L
L
L
L
L
L
L
H
L
H
L
L
H
H
H
L
L
L
L
L
L
L
H
Pin Arrangement
Select
Inputs
Enable
Inputs
Outputs
A
1
16 VCC
B
2
B
C
3
G2A
A
Y0
15 Y0
C
Y1
14 Y1
4
G2A
Y2
13 Y2
G2B
5
G2B
Y3
12 Y3
G1
6
G1
Y4
11 Y4
Y7
7
Y7
Y5
10 Y5
GND
8
Y6
9
(Top view)
2
Y6
Outputs
HD74HCT238
Logic Diagram
G1
G2B
Y0
G2A
Y1
A
Y2
Y3
B
Y4
C
Y5
Y6
Y7
DC Characteristics
Ta = –40 to
+85°C
Ta = 25°C
Test Conditions
Item
Symbol
Min Typ Max Min
Max
Unit
VCC (V)
Input voltage
VIH
2.0
—
—
—
V
4.5 to
5.5
VIL
—
—
0.8 —
0.8
V
4.5 to
5.5
VOH
4.4
—
—
4.4
—
V
4.5
Vin = VIH or VIL I OH = –20 µA
4.18 —
—
4.13
—
4.5
I OH = –4 mA
—
—
0.1 —
0.1
—
—
0.26 —
0.33
Output voltage
VOL
2.0
V
4.5
Vin = VIH or VIL I OL = 20 µA
4.5
I OL = 4 mA
Input current
Iin
—
—
±0.1 —
±1.0
µA
5.5
Vin = VCC or GND
Quiescent supply
current
I CC
—
—
4.0 —
40
µA
5.5
Vin = VCC or GND, Iout = 0 µA
3
HD74HCT238
AC Characteristics (CL = 50 pF, Input tr = tf = 6 ns)
Ta = –40 to
+85°C
Ta = 25°C
Test Conditions
Min Typ Max Min
Max
Unit
VCC (V)
Propagation delay t PLH
—
18
30
—
38
ns
4.5
time
t PHL
—
19
30
—
38
t PLH
—
17
30
—
38
t PHL
—
17
30
—
39
t PLH
—
17
30
—
38
t PHL
—
17
30
—
38
t PLH
—
17
30
—
38
t PHL
—
17
30
—
38
Output rise/fall
time
t TLH
t THL
—
5
15
—
19
ns
4.5
Input capacitance
Cin
—
5
10
—
10
pF
—
Item
4
Symbol
A, B or C to Y
4.5
ns
4.5
G2A to Y
4.5
ns
4.5
G2B to Y
4.5
ns
4.5
4.5
G1 to Y
Unit: mm
19.20
20.00 Max
1
7.40 Max
9
6.30
16
8
1.3
0.48 ± 0.10
2.54 Min 5.06 Max
2.54 ± 0.25
0.51 Min
1.11 Max
7.62
+ 0.13
0.25 – 0.05
0° – 15°
Hitachi Code
JEDEC
EIAJ
Weight (reference value)
DP-16
Conforms
Conforms
1.07 g
Unit: mm
10.06
10.5 Max
9
1
8
1.27
*0.42 ± 0.08
0.40 ± 0.06
0.10 ± 0.10
0.80 Max
*0.22 ± 0.05
0.20 ± 0.04
2.20 Max
5.5
16
0.20
7.80 +– 0.30
1.15
0° – 8°
0.70 ± 0.20
0.15
0.12 M
*Dimension including the plating thickness
Base material dimension
Hitachi Code
JEDEC
EIAJ
Weight (reference value)
FP-16DA
—
Conforms
0.24 g
Unit: mm
9.9
10.3 Max
9
1
8
0.635 Max
*0.42 ± 0.08
0.40 ± 0.06
0.15
*0.22 ± 0.03
0.20 ± 0.03
1.27
0.11
0.14 +– 0.04
1.75 Max
3.95
16
0.10
6.10 +– 0.30
1.08
0° – 8°
0.67
0.60 +– 0.20
0.25 M
*Dimension including the plating thickness
Base material dimension
Hitachi Code
JEDEC
EIAJ
Weight (reference value)
FP-16DN
Conforms
Conforms
0.15 g
Cautions
1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent,
copyright, trademark, or other intellectual property rights for information contained in this document.
Hitachi bears no responsibility for problems that may arise with third party’s rights, including
intellectual property rights, in connection with use of the information contained in this document.
2. Products and product specifications may be subject to change without notice. Confirm that you have
received the latest product standards or specifications before final design, purchase or use.
3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However,
contact Hitachi’s sales office before using the product in an application that demands especially high
quality and reliability or where its failure or malfunction may directly threaten human life or cause risk
of bodily injury, such as aerospace, aeronautics, nuclear power, combustion control, transportation,
traffic, safety equipment or medical equipment for life support.
4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly
for maximum rating, operating supply voltage range, heat radiation characteristics, installation
conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used
beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable
failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other
consequential damage due to operation of the Hitachi product.
5. This product is not designed to be radiation resistant.
6. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document without
written approval from Hitachi.
7. Contact Hitachi’s sales office for any questions regarding this document or Hitachi semiconductor
products.
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