74VHCT138A 3-to-8 Decoder/Demultiplexer
May 2007
74VHCT138A
3-to-8 Decoder/Demultiplexer
Features
■
High Speed: t
PD
=
7.6ns (Typ.) at V
CC
=
5V
■
Low power dissipation: I
CC
=
4µA (Max.) at T
A
=
25°C
■
Power down protection is provided on all inputs and
tm
General Description
The VHCT138A is an advanced high speed CMOS
3-to-8 DECODER fabricated with silicon gate CMOS
technology. It achieves the high speed operation similar
to equivalent Bipolar Schottky TTL while maintaining the
CMOS low power dissipation.
When the device is enabled, 3 Binary Select inputs
(A
0
, A
1
and A
2
) determine which one of the outputs
(O
0
–O
7
) will go LOW. When enable input E
3
is held
LOW or either E
1
or E
2
is held HIGH, decoding function
is inhibited and all outputs go HIGH. E
3
, E
1
and E
2
inputs
are provided to ease cascade connection and for use as
an address decoder for memory systems. Protection
circuits ensure that 0V to 7V can be applied to the input
pins without regard to the supply voltage and to the out-
put pins with V
CC
=
0V. These circuits prevent device
destruction due to mismatched supply and input/output
voltages. This device can be used to interface 3V to 5V
systems and two supply systems such as battery
backup.
outputs
■
Pin and function compatible with 74HCT138
Ordering Information
Order Number
74VHCT138AM
74VHCT138ASJ
74VHCT138AMTC
Package
Number
M16A
M16D
MTC16
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm
Wide
Surface mount packages are also available on Tape and Reel. Specify by appending the suffix letter “X” to the
ordering number.
©1993 Fairchild Semiconductor Corporation
74VHCT138A Rev. 1.2
www.fairchildsemi.com
74VHCT138A 3-to-8 Decoder/Demultiplexer
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol
V
CC
V
IN
V
OUT
Supply Voltage
DC Input Voltage
DC Output Voltage
Note 1
Note 2
I
IK
I
OK
I
OUT
I
CC
T
STG
T
L
Input Diode Current
Output Diode Current
(3)
DC Output Current
DC V
CC
/ GND Current
Storage Temperature
Parameter
Rating
–0.5V to +7.0V
–0.5V to +7.0V
–0.5V to 7.0V
–0.5V to V
CC
+ 0.5V
–20mA
±20mA
±25mA
±75mA
–65°C to +150°C
260°C
Lead Temperature (Soldering, 10 seconds)
Recommended Operating Conditions
(4)
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to absolute maximum ratings.
Symbol
V
CC
V
IN
V
OUT
Supply Voltage
Input Voltage
Output Voltage
Note 1
Note 2
T
OPR
t
r
, t
f
Notes:
1. V
CC
=
0V.
Operating Temperature
Parameter
Rating
4.5V to +5.5V
0V to +5.5V
0V to 5.5V
0V to V
CC
–40°C to +85°C
0
∼
20ns/V
Input Rise and Fall Time, V
CC
=
5.0V ±0.5V
2. HIGH or LOW state. I
OUT
absolute maximum rating must be observed.
3. V
OUT
<
GND, V
OUT
>
V
CC
(Outputs Active).
4. Unused inputs must be held HIGH or LOW. They may not float.
©1993 Fairchild Semiconductor Corporation
74VHCT138A Rev. 1.2
www.fairchildsemi.com
4
74VHCT138A 3-to-8 Decoder/Demultiplexer
DC Electrical Characteristics
T
A
=
25°C
Symbol
V
IH
V
IL
V
OH
V
OL
I
IN
I
CC
I
CCT
I
OFF
T
A
=
–40°C
to +85°C
2.0
0.8
0.8
4.4
3.80
0.1
0.1
0.44
±1.0
20.0
1.50
5.0
µA
µA
mA
µA
V
V
V
V
Parameter
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output
Voltage
LOW Level Output
Voltage
Input Leakage Current
Quiescent Supply
Current
Maximum I
CC
/ Input
Output Leakage Current
V
CC
(V)
4.5 – 5.5
4.5 – 5.5
4.5
4.5
0 – 5.5
5.5
5.5
0
Conditions
Min.
2.0
Typ. Max. Min. Max. Units
V
IN
=
V
IH
I
OH
=
–50µA
or V
IL
I
OH
=
–8mA
V
IN
=
V
IH
I
OL
=
50µA
or V
IL
I
OL
=
8mA
V
IN
=
5.5V or GND
V
IN
=
V
CC
or GND
V
IN
=
3.4V, All other
inputs
=
V
CC
or GND
V
OUT
=
5.5V
4.4
3.94
4.5
0.0
0.36
±0.1
4.0
1.35
0.5
AC Electrical Characteristics
T
A
=
25°C
Symbol
t
PLH
, t
PHL
t
PLH
, t
PHL
t
PLH
, t
PHL
C
IN
C
PD
T
A
=
–40°C to
+85°C
Max.
10.4
11.4
9.1
10.1
9.6
10.6
10
Parameter
Propagation Delay,
A
n
to O
n
Propagation Delay,
E
3
to O
n
Propagation Delay,
E
1
or E
2
to O
n
Input Capacitance
Power Dissipation
Capacitance
V
CC
(V)
Conditions
C
L
=
50pF
Min.
Typ.
7.6
8.1
6.6
7.1
7.0
7.5
4
49
Min.
1.0
1.0
1.0
1.0
1.0
1.0
Max.
12.0
13.0
10.5
11.5
11.0
12.0
10
Units
ns
ns
ns
pF
pF
5.0 ± 0.5 C
L
=
15pF
5.0 ± 0.5 C
L
=
15pF
C
L
=
50pF
5.0 ± 0.5 C
L
=
15pF
C
L
=
50pF
V
CC
=
Open
(5)
Note:
5. 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
• V
CC
• f
IN
+ I
CC
©1993 Fairchild Semiconductor Corporation
74VHCT138A Rev. 1.2
www.fairchildsemi.com
5
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