TC74HC238AP/AF
TOSHIBA CMOS Digital Integrated Circuit
Silicon Monolithic
TC74HC238AP, TC74HC238AF
3-to-8 Line Decoder
The TC74HC238A is a high speed CMOS 3-to-8 DECODER
fabricated with silicon gate C
2
MOS technology.
It achieves the high speed operation similar to equivalent
LSTTL while maintaining the CMOS low power dissipation.
When the device is enabled, 3 Binary Select inputs (A, B and C)
determine which one of the outputs (Y0-Y7) will go high.
When enable input G1 is held low or either
G 2 A
or
G2B
is
held high, decoding function is inhibited and all the outputs go
low. G1,
G 2 A
, and
G2B
inputs are provided ease cascade
connection and for use as an adress decoder for memory systems.
All inputs are equipped with protection circuits against static
discharge or transient excess voltage.
TC74HC238AP
TC74HC238AF
Features
•
•
•
•
•
•
•
•
High speed: t
pd
= 14 ns (typ.) at V
CC
= 5 V
Low power dissipation: I
CC
= 4
μA
(max) at Ta = 25°C
High noise immunity: V
NIH
= V
NIL
= 28% V
CC
(min)
Output drive capability: 10 LSTTL loads
Symmetrical output impedance: |I
OH
| = I
OL
= 4 mA (min)
∼
Balanced propagation delays: t
pLH
−
t
pHL
Wide operating voltage range: V
CC
(opr) = 2 to 6 V
Pin and function compatible with 74LS238
Weight
DIP16-P-300-2.54A
SOP16-P-300-1.27A
: 1.00 g (typ.)
: 0.18 g (typ.)
Pin Assignment
Start of commercial production
1987-11
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2014-03-01
TC74HC238AP/AF
IEC Logic Symbol
Truth Table
Inputs
Enable
G1
G2 A
Outputs
Select
G2B
X
X
H
L
L
L
L
L
L
L
L
C
X
X
X
L
L
L
L
H
H
H
H
B
X
X
X
L
L
H
H
L
L
H
H
A
X
X
X
L
H
L
H
L
H
L
H
Y0
L
L
L
H
L
L
L
L
L
L
L
Y1
L
L
L
L
H
L
L
L
L
L
L
Y2
L
L
L
L
L
H
L
L
L
L
L
Y3
L
L
L
L
L
L
H
L
L
L
L
Y4
L
L
L
L
L
L
L
H
L
L
L
Y5
L
L
L
L
L
L
L
L
H
L
L
Y6
L
L
L
L
L
L
L
L
L
H
L
Y7
L
L
L
L
L
L
L
L
L
L
H
Selected
Output
None
None
None
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
L
X
X
H
H
H
H
H
H
H
H
X
H
X
L
L
L
L
L
L
L
L
X: Don’t care
System diagram
2
2014-03-01
TC74HC238AP/AF
Absolute Maximum Ratings (Note 1)
Characteristics
Supply voltage range
DC input voltage
DC output voltage
Input diode current
Output diode current
DC output current
DC V
CC
/ground current
Power dissipation
Storage temperature
Symbol
V
CC
V
IN
V
OUT
I
IK
I
OK
I
OUT
I
CC
P
D
T
stg
Rating
−
0.5 to 7
−
0.5 to V
CC
+
0.5
−
0.5 to V
CC
+
0.5
±
20
±
20
±
25
±
50
Unit
V
V
V
mA
mA
mA
mA
mW
°C
500 (DIP) (Note 2)/180 (SOP)
−
65 to 150
Note 1: Exceeding any of the absolute maximum ratings, even briefly, lead to deterioration in IC performance or
even destruction.
Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the
significant change in temperature, etc.) may cause this product to decrease in the reliability significantly
even if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute
maximum ratings and the operating ranges.
Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook
(“Handling Precautions”/“Derating Concept and Methods”) and individual reliability data (i.e. reliability test
report and estimated failure rate, etc).
Note 2: 500 mW in the range of Ta
= −40°C
to 65°C. From Ta
=
65°C to 85°C a derating factor of
−10
mW/°C shall
be applied until 300 mW.
Operating Ranges (Note)
Characteristics
Supply voltage
Input voltage
Output voltage
Operating temperature
Symbol
V
CC
V
IN
V
OUT
T
opr
Rating
2 to 6
0 to V
CC
0 to V
CC
−
40 to 85
Unit
V
V
V
°C
0 to 1000 (V
CC
=
2.0 V)
Input rise and fall time
t
r
, t
f
0 to 500 (V
CC
=
4.5 V)
0 to 400 (V
CC
=
6.0 V)
ns
Note:
The operating ranges must be maintained to ensure the normal operation of the device.
Unused inputs must be tied to either V
CC
or GND.
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2014-03-01
TC74HC238AP/AF
Electrical Characteristics
DC Characteristics
Characteristics
Symbol
Test Condition
V
CC
(V)
2.0
High-level input
voltage
V
IH
⎯
Ta
=
25°C
Min
1.50
3.15
4.20
⎯
⎯
⎯
Ta
=
−
40 to 85°C
Max
⎯
⎯
⎯
Unit
Typ.
⎯
⎯
⎯
⎯
⎯
⎯
Min
1.50
3.15
4.20
⎯
⎯
⎯
Max
⎯
⎯
⎯
4.5
6.0
2.0
V
0.50
1.35
1.80
⎯
⎯
⎯
⎯
⎯
0.50
1.35
1.80
⎯
⎯
⎯
⎯
⎯
Low-level input
voltage
V
IL
⎯
4.5
6.0
2.0
V
1.9
4.4
5.9
4.18
5.68
⎯
⎯
⎯
⎯
⎯
⎯
⎯
2.0
4.5
6.0
4.31
5.80
0.0
0.0
0.0
0.17
0.18
⎯
⎯
1.9
4.4
5.9
4.13
5.63
⎯
⎯
⎯
⎯
⎯
⎯
⎯
I
OH
= −
20
μ
A
High-level output
voltage
V
OH
V
IN
=
V
IH
or V
IL
I
OH
= −
4 mA
I
OH
= −
5.2 mA
I
OL
=
20
μ
A
Low-level output
voltage
V
OL
V
IN
=
V
IH
or V
IL
I
OL
=
4 mA
I
OL
=
5.2 mA
Input leakage
current
Quiescent supply
current
I
IN
I
CC
V
IN
=
V
CC
or GND
V
IN
=
V
CC
or GND
4.5
6.0
4.5
6.0
2.0
4.5
6.0
4.5
6.0
6.0
6.0
V
0.1
0.1
0.1
0.26
0.26
±
0.1
0.1
0.1
0.1
0.33
0.33
±
1.0
μ
A
μ
A
V
4.0
40.0
AC Characteristics
(C
L
=
15 pF, V
CC
=
5 V, Ta
=
25°C, input: t
r
=
t
f
=
6 ns)
Characteristics
Output transition time
Propagation delay time
(A, B, C-Y)
Propagation delay time
(G, G -Y)
Symbol
t
TLH
t
THL
t
pLH
t
pHL
t
pLH
t
pHL
Test Condition
⎯
Min
⎯
Typ.
4
Max
8
Unit
ns
⎯
⎯
14
26
ns
⎯
⎯
14
26
ns
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2014-03-01
TC74HC238AP/AF
AC Characteristics
(C
L
=
50 pF, input: t
r
=
t
f
=
6 ns)
Characteristics
Symbol
Test Condition
V
CC
(V)
t
TLH
t
THL
t
pLH
t
pHL
t
pLH
t
pHL
C
IN
C
PD
(Note)
2.0
⎯
Ta
=
25°C
Min
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
Ta
=
−
40 to 85°C
Max
75
15
13
150
30
26
150
30
26
10
⎯
Unit
Typ.
30
8
7
50
17
15
50
17
15
5
53
Min
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
Max
95
19
16
190
38
32
190
38
32
10
⎯
Output transition time
4.5
6.0
2.0
ns
Propagation delay
time
(A, B, C-Y)
Propagation delay
time
(G, G -Y)
Input capacitance
Power dissipation
capacitance
⎯
4.5
6.0
2.0
ns
⎯
4.5
6.0
⎯
⎯
ns
pF
pF
Note:
C
PD
is defined as the value of the internal equivalent capacitance which is calculated from the operating
current consumption without load.
Average operating current can be obtained by the equation:
I
CC
(opr)
=
C
PD
½V
CC
½f
IN
+
I
CC
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2014-03-01
