STMICROELECTRONICS 74VHCT238ATTR

74VHCT238A
3 TO 8 LINE DECODER
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HIGH SPEED: tPD = 5.5 ns (TYP.) at VCC = 5V
LOW POWER DISSIPATION:
ICC = 4 µA (MAX.) at TA=25°C
COMPATIBLE WITH TTL OUTPUTS:
VIH = 2V (MIN.), VIL = 0.8V (MAX)
POWER DOWN PROTECTION ON INPUTS
& OUTPUTS
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 8 mA (MIN)
BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
OPERATING VOLTAGE RANGE:
VCC(OPR) = 4.5V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 238
IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The 74VHCT238A is an advanced high-speed
CMOS 3 TO 8 LINE DECODER fabricated with
sub-micron silicon gate and double-layer metal
wiring C2MOS technology.
When the device is enabled, 3 binary select inputs
(A, B, and C) determine which one of the outputs
will go high. If enable input G1 is held low or either
G2A or G2B is held high, decoding function is
inhibited and all the 8 outputs go to low.
SOP
TSSOP
Table 1: Order Codes
PACKAGE
T&R
SOP
TSSOP
74VHCT238AMTR
74VHCT238ATTR
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 to interface 5V to 3V since all
inputs are equipped with TTL threshold.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
Figure 1: Pin Connection And IEC Logic Symbols
December 2004
Rev. 3
1/12
74VHCT238A
Figure 2: Input Equivalent Circuit
Table 2: Pin Description
PIN N°
SYMBOL
1, 2, 3
4, 5
6
15, 14, 13,
12, 11, 10, 9,
7
8
16
A, B, C
G2A, G2B
G1
Y0 to Y7
GND
VCC
NAME AND FUNCTION
Address Inputs
Enable Inputs
Enable Input
Outputs
Ground (0V)
Positive Supply Voltage
Table 3: Truth Table
INPUTS
OUTPUTS
ENABLE
SELECT
G2B
G2A
G1
C
B
A
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
X
H
L
L
L
L
L
L
L
L
X
H
X
L
L
L
L
L
L
L
L
L
X
X
H
H
H
H
H
H
H
H
X
X
X
L
L
L
L
H
H
H
H
X
X
X
L
L
H
H
L
L
H
H
X
X
X
L
H
L
H
L
H
L
H
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
X : Don’t Care
Figure 3: Logic Diagram
This logic diagram has not be used to estimate propagation delays
2/12
74VHCT238A
Table 4: Absolute Maximum Ratings
Symbol
VCC
Parameter
Value
Unit
Supply Voltage
-0.5 to +7.0
V
VI
DC Input Voltage
-0.5 to +7.0
V
VO
DC Output Voltage (see note 1)
-0.5 to +7.0
V
VO
DC Output Voltage (see note 2)
-0.5 to VCC + 0.5
V
IIK
DC Input Diode Current
- 20
mA
IOK
DC Output Diode Current
± 20
mA
IO
DC Output Current
± 25
mA
ICC or IGND DC VCC or Ground Current
Tstg
Storage Temperature
TL
Lead Temperature (10 sec)
± 50
mA
-65 to +150
°C
300
°C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
1) VCC = 0V
2) High or Low State
Table 5: Recommended Operating Conditions
Symbol
VCC
Parameter
Supply Voltage
Value
Unit
4.5 to 5.5
V
VI
Input Voltage
0 to 5.5
V
VO
Output Voltage (see note 1)
0 to 5.5
V
VO
Output Voltage (see note 2)
Top
Operating Temperature
dt/dv
Input Rise and Fall Time (see note 3) (VCC = 5.0 ± 0.5V)
0 to VCC
V
-55 to 125
°C
0 to 20
ns/V
1) VCC = 0V
2) High or Low State
3) VIN from 0.8V to 2V
3/12
74VHCT238A
Table 6: DC Specifications
Test Condition
Symbol
VIH
VIL
VOH
VOL
II
ICC
+ICC
IOPD
Parameter
TA = 25°C
VCC
(V)
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
4.5 to
5.5
4.5 to
5.5
Value
Min.
Typ.
Max.
2
-40 to 85°C
-55 to 125°C
Min.
Min.
Max.
2
0.8
Max.
2
0.8
Unit
V
0.8
V
4.5
IO=-50 µA
4.4
4.5
IO=-8 mA
3.94
Low Level Output
Voltage
4.5
IO=50 µA
0.1
0.1
0.1
4.5
IO=8 mA
0.36
0.44
0.55
Input Leakage
Current
Quiescent Supply
Current
Additional Worst
Case Supply
Current
0 to
5.5
VI = 5.5V or GND
± 0.1
± 1.0
± 1.0
µA
5.5
VI = VCC or GND
4
40
40
µA
5.5
One Input at 3.4V,
other input at VCC
or GND
1.35
1.5
1.5
mA
0
VOUT = 5.5V
0.5
5.0
5.0
µA
Output Leakage
Current
4.5
0.0
4.4
4.4
3.8
3.7
V
V
Table 7: AC Electrical Characteristics (Input tr = tf = 3ns)
Test Condition
Symbol
Parameter
tPLH
tPHL
Propagation Delay
Time A,B,C to Y
tPLH
tPHL
Propagation Delay
Time G1 to Y
tPLH
tPHL
Propagation Delay
Time
G2A, G2B to Y
VCC (*) CL
(V)
(pF)
Value
TA = 25°C
Min.
-40 to 85°C
-55 to 125°C
Typ.
Max.
Min.
Max.
Min.
Max.
5.0
5.0
5.0
5.0
5.0
15
50
15
50
15
5.5
7.0
5.4
6.9
5.7
8.1
10.1
8.1
10.1
8.1
1.0
1.0
1.0
1.0
1.0
9.5
11.5
9.5
11.5
9.5
1.0
1.0
1.0
1.0
1.0
9.5
11.5
9.5
11.5
9.5
5.0
50
7.2
10.1
1.0
11.5
1.0
11.5
Unit
ns
ns
ns
(*) Voltage range is 5.0V ± 0.5V
Table 8: Capacitive Characteristics
Test Condition
Symbol
Value
TA = 25°C
Parameter
Min.
Typ.
Max.
10
CIN
Input Capacitance
6
CPD
Power Dissipation
Capacitance
(note 1)
37
-40 to 85°C
-55 to 125°C
Min.
Min.
Max.
10
Unit
Max.
10
pF
pF
1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x fIN + ICC
4/12
74VHCT238A
Figure 4: Test Circuit
CL =15/50pF or equivalent (includes jig and probe capacitance)
RT = ZOUT of pulse generator (typically 50Ω)
Figure 5: Waveform - Propagation Delays For Inverting Outputs (f=1MHz; 50% duty cycle)
5/12
74VHCT238A
Figure 6: Waveform - Propagation Delays For Non-inverting Outputs (f=1MHz; 50% duty cycle)
6/12
74VHCT238A
SO-16 MECHANICAL DATA
DIM.
mm.
MIN.
TYP
A
a1
inch
MAX.
MIN.
TYP.
1.75
0.1
0.068
0.25
a2
MAX.
0.004
0.010
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
e3
0.050
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
S
0.62
0.024
8° (max.)
0016020D
7/12
74VHCT238A
TSSOP16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
TYP
A
MAX.
MIN.
TYP.
MAX.
1.2
A1
0.05
A2
0.8
b
0.047
0.15
0.002
0.004
0.006
1.05
0.031
0.039
0.041
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
1
e
0.65 BSC
K
0˚
L
0.45
A
0.60
0.0256 BSC
8˚
0˚
0.75
0.018
8˚
0.024
0.030
A2
A1
b
e
K
c
L
E
D
E1
PIN 1 IDENTIFICATION
1
0080338D
8/12
74VHCT238A
Tape & Reel SO-16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
A
TYP
MAX.
MIN.
330
MAX.
12.992
C
12.8
D
20.2
0.795
N
60
2.362
T
13.2
TYP.
0.504
22.4
0.519
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
74VHCT238A
Tape & Reel TSSOP16 MECHANICAL DATA
mm.
inch
DIM.
MIN.
A
MAX.
MIN.
330
13.2
TYP.
MAX.
12.992
C
12.8
D
20.2
0.795
N
60
2.362
T
10/12
TYP
0.504
22.4
0.519
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
74VHCT238A
Table 9: Revision History
Date
Revision
16-Dec-2004
3
Description of Changes
Order Codes Revision - pag. 1.
11/12
74VHCT238A
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