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74VHCT138A
3 TO 8 LINE DECODER (INVERTING)
■ HIGH SPEED: t
■ LOW POWER DISSIPATION:
I
= 4 µA (MAX.) at TA=25°C
CC
■ COMPATIBLE WITH TTL OUTP U TS:
V
= 2V (M IN.), V
IH
■ POWER DOWN PROTECTION ON INPUTS
= 7.6 ns (TYP.) at VCC = 5V
PD
= 0.8V (MAX)
IL
& OUTPUTS
■ SYMMETRICAL OUTPUT IMPEDANCE:
|I
| = IOL = 8 mA (MIN)
OH
■ BALANCED PROPAGATION DELAYS:
t
≅ t
PLH
PHL
■ OPERATING VOLTAGE RANGE:
V
(OPR) = 4.5V to 5.5V
CC
■ PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 138
■ IMPROVED LATCH-UP IMMUNITY
■ LOW NOISE: V
= 0.8V (MAX.)
OLP
DESCRIPTION
The 74VHCT138A is an advanced high-speed
CMOS 3 TO 8 LINE DECODER (INVERTING)
fabricated with sub-micron silicon gate and
double-layer metal wiring C
2
MOS technology.
If the device is enabled, 3 binary select inputs (A,
B, and C) determine which one of the outputs will
go low. When enable input G1 is held low or either
G2A
or G2B is held high, the d ec oding fun ction is
inhibited and all the 8 outputs go to high.
TSSOPSOP
Table 1: Order Codes
PACKAGE T & R
SOP 74VHCT138AMTR
TSSOP 74VHCT138ATTR
The three enable inputs are provided to ease
cascade connection and application of address
decoders for memory systems.
Power down protection is provided on all inputs
and outputs and 0 to 7V can be accepted on
inputs with no regard to the supply voltage. This
device can be used t o interf ace 5V to 3V s ince al l
inputs are equipped with TTL threshold.
All inputs and outputs are equipped with
protection circuits against static disc harge, giving
them 2KV ESD immunity and transient excess
voltage.
Figure 1: Pin Connection And IEC Logic Symbols
Rev. 3
1/12December 2004
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74VHCT138A
Figure 2: Input Equivalent Circuit Table 2: Pin Description
PIN N° SYMBOL NAME AND FUNCTION
1, 2, 3 A, B, C Address Inputs
4, 5 G2A
6 G1 Enable Input
15, 14, 13,
12, 1 1, 10, 9,
7
8 GND Ground (0V)
16 V
Table 3: Truth Table
, G2B Enable Inputs
to Y7 Outputs
Y0
CC
Positive Supply Voltage
INPUTS
ENABLE SELECT
G2B
X : Don’t Care
G2A G1CBAY0Y1 Y2 Y3 Y4 Y5 Y6 Y7
XXLXXXHHHHHHHH
XHXXXXHHHHHHHH
HXXXXXHHHHHHHH
LLHLLLLHHHHHHH
LLHLLHHLHHHHHH
LLHLHLHHLHHHHH
LLHLHHHHHLHHHH
LLHHLLHHHHLHHH
LLHHLHHHHHHLHH
LLHHHLHHHHHHLH
LLHHHHHHHHHHHL
OUTPUTS
Figure 3: Logic Diagram
This logi c di agram has not be used to est i m ate propaga tion delays
2/12
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74VHCT138A
Table 4: Absolute Maximum Ratings
Symbol Parameter Value Unit
V
V
V
V
I
I
OK
I
or I
I
CC
T
T
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
1) V
CC
2) High or Low State
Table 5: Recommended Operating Conditions
Symbol Parameter Value Unit
V
V
V
V
T
dt/dv
Supply Voltage
CC
DC Input Voltage
I
DC Output Voltage (see note 1)
O
DC Output Voltage (see note 2) -0.5 to VCC + 0.5
O
DC Input Diode Current
IK
DC Output Diode Current
DC Output Current
O
DC VCC or Ground Current
GND
Storage Temperature
stg
Lead Temperature (10 sec)
L
= 0V
Supply Voltage
CC
Input Voltage
I
Output Voltage (see note 1)
O
Output Voltage (see note 2) 0 to V
O
Operating Temperature
op
Input Rise and Fall Time (see note 3) (V
= 5.0 ± 0.5V)
CC
-0.5 to +7.0 V
-0.5 to +7.0 V
-0.5 to +7.0 V
- 20 mA
± 20 mA
± 25 mA
± 50 mA
-65 to +150 °C
300 °C
4.5 to 5.5 V
0 to 5.5 V
0 to 5.5 V
CC
-55 to 125 °C
0 to 20 ns/V
V
V
1) V
= 0V
CC
2) High or Low State
3) V
from 0.8V to 2V
IN
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74VHCT138A
Table 6: DC Specifications
Symbol Parameter
V
V
V
+I
I
High Level Input
IH
Voltage
Low Level Input
V
IL
Voltage
High Level Output
OH
Voltage
Low Level Output
OL
Voltage
I
Input Leakage
I
Current
I
Quiescent Supply
CC
Current
Additional Worst
CC
Case Supply
Current
Output Leakage
OPD
Current
Test Condition Value
= 25°C
T
V
CC
(V)
4.5 to
5.5
A
Min. Typ. Max. Min. Max. Min. Max.
222V
4.5 to
5.5
4.5
4.5
4.5
4.5
0 to
VI = 5.5V or GND
5.5
V
5.5
I
O
=-8 mA
I
O
=50 µA
I
O
=8 mA
I
O
= VCC or GND
I
4.4 4.5 4.4 4.4
3.94 3.8 3.7
0.0 0.1 0.1 0.1
=-50 µA
One Input at 3.4V,
other input at V
5.5
CC
or GND
= 5.5V
0
V
OUT
-40 to 85°C -55 to 125°C
Unit
0.8 0.8 0.8 V
V
0.36 0.44 0.55
V
± 0.1 ± 1.0 ± 1.0 µA
44040µA
1.35 1.5 1.5 mA
0.5 5.0 5.0 µA
Table 7: AC Electrical Characteristics (Input t
Test Condition Value
Symbol Parameter
t
Propagation Delay
PLH
t
t
t
t
t
(*) Voltage range is 5.0V ± 0.5V
Time
PHL
A, B, C, to Y
Propagation Delay
PLH
Time
PHL
G1 to Y
Propagation Delay
PLH
Time
PHL
G2A
, G2B to Y
V
(V)
5.0
5.0
5.0
5.0
5.0
5.0
C
CC
L
(pF)
(*)
15 7.6 10.4 1.0 12.0 1.0 12.0
(*)
50 8.1 11.4 1.0 13.0 1.0 13.0
(*)
15 6.6 9.1 1.0 10.5 1.0 10.5
(*)
50 7.1 10.1 1.0 11.5 1.0 11.5
(*)
15 7.0 9.6 1.0 11.0 1.0 11.0
(*)
50 7.5 10.6 1.0 12.0 1.0 12.0
Table 8: Capacitive Characteristics
Test Condition Value
Symbol Parameter
C
C
Input Capacitance
IN
Power Dissipation
PD
Capacitance
(note 1)
= tf = 3ns)
r
= 25°C
T
A
-40 to 85°C -55 to 125°C
Min. Typ. Max. Min. Max. Min. Max.
= 25°C
T
A
-40 to 85°C -55 to 125°C
Min. Typ. Max. Min. Max. Min. Max.
610 10 10pF
36 pF
Unit
ns
ns
ns
Unit
1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without
load. (R ef er to Test Circ ui t). Averag e operating current can be obtained by t he following equation. I
= CPD x VCC x fIN + I
CC(opr)
CC
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74VHCT138A
Figure 4: Test Circuit
CL =15/50pF or equivalent (i ncludes jig an d probe capac i tance)
= Z
R
Figure 5: Waveform - Propagation Delays For Inverting Outputs (f=1MHz; 50% duty cycle)
of pulse generator (typically 50Ω)
T
OUT
5/12
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74VHCT138A
Figure 6: Waveform - Propagation Delays For Non-inverting Outputs (f=1MHz; 50% duty cyc le)
6/12
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SO-16 MECHANICAL DATA
74VHCT138A
DIM.
A 1.75 0.068
a1 0.1 0.25 0.004 0.010
a2 1.64 0.063
b 0.35 0.46 0.013 0.018
b1 0.19 0.25 0.007 0.010
C 0.5 0.019
c1 45° (typ.)
D 9.8 10 0.385 0.393
E 5.8 6.2 0.228 0.244
e 1.27 0.050
e3 8.89 0.350
F 3.8 4.0 0.149 0.157
G 4.6 5.3 0.181 0.208
L 0.5 1.27 0.019 0.050
M 0.62 0.024
S8° (max.)
MIN. TYP MAX. MIN. TYP. MAX.
mm. inch
0016020D
7/12
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74VHCT138A
TSSOP16 MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 1.2 0.047
A1 0.05 0.15 0.002 0.004 0.006
A2 0.8 1 1.05 0.031 0.039 0.041
b 0.19 0.30 0.007 0.012
c 0.09 0.20 0.004 0.0079
D 4.9 5 5.1 0.193 0.197 0.201
E 6.2 6.4 6.6 0.244 0.252 0.260
E1 4.3 4.4 4.48 0.169 0.173 0.176
e 0.65 BSC 0.0256 BSC
K0˚ 8˚0˚ 8˚
L 0.45 0.60 0.75 0.018 0.024 0.030
A2
A
A1
b
e
c
K
L
E
D
E1
PIN 1 IDENTIFICATION
8/12
1
0080338D
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74VHCT138A
Tape & Reel SO-16 MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.45 6.65 0.254 0.262
Bo 10.3 10.5 0.406 0.414
Ko 2.1 2.3 0.082 0.090
Po 3.9 4.1 0.153 0.161
P 7.9 8.1 0.311 0.319
9/12
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74VHCT138A
Tape & Reel TSSOP16 MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.7 6.9 0.264 0.272
Bo 5.3 5.5 0.209 0.217
Ko 1.6 1.8 0.063 0.071
Po 3.9 4.1 0.153 0.161
P 7.9 8.1 0.311 0.319
10/12
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Table 9: Revision History
Date Revision Description of Changes
16-Dec-2004 3 Order Codes Revision - pag. 1.
74VHCT138A
11/12
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74VHCT138A
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