PHILIPS TL431ACD

INTEGRATED CIRCUITS
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
Product specification
1997 Feb 25
Philips Semiconductors
Product specification
Adjustable precision shunt regulators
DESCRIPTION
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
PIN CONFIGURATIONS
The TL431 and TL431A are 3-terminal adjustable shunt regulators
with specified thermal stability over applicable automotive and
commercial temperature ranges. The output voltage may be set to
any value between VREF (approximately 2.5V) and 36V with two
external resistors (see Figure 4). These devices have a typical
output impedance of 0.2Ω. Active output circuitry provides a very
sharp turn-on characteristic, making these devices excellent
replacements for zener diodes in many applications like on-board
regulation, adjustable power supplies and switching power supplies.
M, D Package
TOP VIEW
CATHODE
1
8
REF
ANODE
2
7
ANODE
ANODE
3
6
ANODE
NC
4
5
NC
SOT96-1
The TL431C and TL431AC are characterized for operation from
0°C to +70°C; the TL431I and TL431AI are characterized for
operation from –40°C to +85°C.
N, P Package
TOP VIEW
FEATURES
• Equivalent full-range temperature coefficient: 30ppm/°C
• 0.2Ω typical output impedance
• Sink current capability: 1mA to 100mA
• Low output noise
• Adjustable output voltage: VREF to 36V
CATHODE
1
8
REF
NC
2
7
NC
NC
3
6
ANODE
NC
4
5
NC
SOT97-1
Z, LP, U Package
CATHODE
ANODE
SOT54
REF
SL01167
Figure 1. Pin Configuration
ORDERING INFORMATION
DESCRIPTION
TEMPERATURE
RANGE
2
0°C to +70°C
3-Pin Plastic TO92 2
0°C to +70°C
3-Pin Plastic TO92
INDUSTRY STANDARD
PART NUMBER
ORDER CODE
DWG #
TL431CLP
TL431CLPU
SOT54
TL431ACLP
TL431ACLPU
SOT54
2
–40°C to +85°C
TL431ILP
TL431ILPU
SOT54
3-Pin Plastic TO92 2
–40°C to +85°C
TL431AILP
TL431AILPU
SOT54
3-Pin Plastic TO92 2
0°C to +70°C
LM431ACZ
LM431ACZU
SOT54
8-Pin Plastic Small Outline (SO) package
0°C to +70°C
TL431CD
TL431CD
SOT96-1
8-Pin Plastic Small Outline (SO) package
–40°C to +85°C
TL431ID
TL431ID
SOT96-1
8-Pin Plastic Small Outline (SO) package
0°C to +70°C
TL431ACD
TL431ACD
SOT96-1
8-Pin Plastic Small Outline (SO) package
–40°C to +85°C
TL431AID
TL431AID
SOT96-1
8-Pin Plastic Small Outline (SO) package
0°C to +70°C
LM431ACM
LM431ACMD
SOT96-1
8-Pin Plastic Dual In-Line package (DIP)
0°C to +70°C
TL431CP
TL431CPN
SOT97-1
8-Pin Plastic Dual In-Line package (DIP)
–40°C to +85°C
TL431IP
TL431IPN
SOT97-1
8-Pin Plastic Dual In-Line package (DIP)
0°C to +70°C
TL431ACP
TL431ACPN
SOT97-1
8-Pin Plastic Dual In-Line package (DIP)
–40°C to +85°C
TL431AIP
TL431AIPN
SOT97-1
3-Pin Plastic TO92
NOTE:
1. SYMBOL INFORMATION: Parts will be marked with product name including temperature and electrical grade desginators, but not the
package identifier.
2. TO92 is normally shipped in bulk, i.e., in plastic bags (containing 1,000 parts), 5 bags per box. Tape and reel (or ammo box) is an option.
See page 15 for information.
1997 Feb 25
2
853–1927 17795
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
ABSOLUTE MAXIMUM RATINGS
SYMBOL
VKA
PARAMETER
RATING
Cathode voltage (see Note 1)
UNITS
37
V
–100 to +150
mA
Reference input current range
0.05 to 10
mA
Tamb
Operating free-air temperature range
C suffix
I suffix
0 to +70
–40 to +85
°C
°C
TSTG
Temperature storage range
–65 to 150
°C
Lead temperature 1.6mm (1/16 in.) from case for 10 sec: D or P pkgs
260
°C
Lead temperature 1.6mm (1/16 in.) from case for 60 sec: LP pkg
300
°C
Continuous cathode current range
NOTE:
1. Voltage values are with respect to the anode terminal unless otherwise noted.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
MIN
MAX
UNITS
VKA
Cathode voltage
VREF
36
V
IK
Cathode current
1
100
mA
Table 1. Dissipation Rating Table – Free-Air Temperature
Package
Derating Factor Above Tamb
= 25°C
Tamb = 25°C
Power Rating
Tamb = 70°C
Power Rating
Tamb = 85°C
Power Rating
D
5.8mW/°C
725mW
464mW
429mW
LP
6.2mW/°C
775mW
496mW
403mW
P
8.0mW/°C
1000mW
640mW
520mW
CATHODE
R4
800
R3
800
C1
20p
Q5
REF
Q3
Q4
Q2
QD6
Q1
R2
150
Q7
R5
3.28K
R11
2.4K
R7
320
R10
7.2K
R1
10K
Qq1
C2
20p
Q9
Q10
Q11
Q8
QD2
R8
1000
R9
800
ANODE
SL01188
Figure 2. Equivalent Schematic
1997 Feb 25
3
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
DC ELECTRICAL CHARACTERISTICS
25°C free-air temperature, unless otherwise stated.
LIMITS
SYMBOL
VREF
TEST
CKT
PARAMETER
UNIT
MIN
TYP
MAX
MIN
TYP
MAX
2495
2520
2440
2495
2550
mV
4
15
4
17
mV
∆VKA = 10V – VREF
–1.4
–2.7
–1.4
–2.7
∆VKA = 36V – 10V
–1
–2
–1
–2
IK = 10mA, R1 = 10kΩ, R2 = ∞
2
4
2
4
µA
Fig. 4
IK = 10mA, R1 = 10kΩ, R2 = ∞,
Tamb = full range2
0.8
1.2
0.4
1.2
µA
Minimum cathode current
for regulation
Fig. 3
VKA = VREF
0.4
0.6
0.4
1
mA
Off-state cathode current
Fig. 5
0.1
0.5
0.1
1
µA
Dynamic impedance4
Fig. 3
VKA = 36V, VREF = 0
VKA = VREF, IK = 1mA to 100mA,
f ≤ 1kHz
0.2
0.5
0.2
0.5
Ω
Fig. 3
VKA = VREF, IK = 10mA
VREF(dev)
Deviation of reference input
voltage over full
temperature range3
Fig. 3
VKA = VREF, IK = 10mA,
Tamb = full range2
V REF
V KA
Ratio of change in reference
input
in
ut voltage to the change
in cathode voltage
Fig 4
Fig.
IK = 10mA
IREF
Reference input current
Fig. 4
Deviation of reference input
current over full temperature
range3
IMIN
IOFF
| ZKA |
TL431C/LM431AC
2470
Reference input voltage
IREF(dev)
TL431AC
TEST CONDITIONS
mV/V
25°C free-air temperature, unless otherwise stated.
LIMITS
SYMBOL
VREF
TEST
CKT
PARAMETER
TL431AI
TEST CONDITIONS
TL431I
UNIT
MIN
TYP
MAX
MIN
TYP
MAX
2470
2495
2520
2440
2495
2550
mV
5
25
5
30
mV
∆VKA = 10V – VREF
–1.4
–2.7
–1.4
–2.7
∆VKA = 36V – 10V
–1
–2
–1
–2
Reference input voltage
Fig. 3
VKA = VREF, IK = 10mA
VREF(dev)
Deviation of reference input
voltage over full
temperature range3
Fig. 3
VKA = VREF, IK = 10mA,
Tamb = full range2
V REF
V KA
Ratio of change in reference
input
in
ut voltage to the change
in cathode voltage
Fig 4
Fig.
IK = 10mA
IREF
Reference input current
Fig. 4
IK = 10mA, R1 = 10kΩ, R2 = ∞
2
4
2
4
µA
Deviation of reference input
current over full temperature
range3
Fig. 4
IK = 10mA, R1 = 10kΩ, R2 = ∞,
Tamb = full range2
0.8
2.5
0.8
2.5
µA
IMIN
Minimum cathode current
for regulation
Fig. 3
VKA = VREF
0.4
0.7
0.4
1
µA
IOFF
Off-state cathode current
Fig. 5
VKA = 36V, VREF = 0
0.1
0.5
0.1
1
µA
Fig. 3
VKA = VREF, IK = 1mA to 100mA,
f ≤ 1kHz
0.2
0.5
0.2
0.5
Ω
IREF(dev)
| ZKA |
Dynamic impedance4
mV/V
NOTES:
2. Full temperature range is –40°C to +85°C for the TL431I and TL431AI, and 0°C to +70°C for the TL431C and TL431AC.
3. The deviation parameters VREF(dev) and IREF(dev) are defined as the differences between the maximum and minimum values obtained over
the rated termperature range. The average full-range temperature coefficient of the reference input voltage, αVREF, is defined as:
| V REF |
ppm
deg
C
V REF(dev)
V REF at 25 oC
10 6
Max VREF
VREF(dev)
T amb
Min VREF
∆Tamb
where ∆Tamb is the rated operating free-air temperature range of the device.
1997 Feb 25
4
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
αVREF can be positive or negative depending on whether minimum VREF of maximum VREF, respectively, occurs at the lower temperature.
Example: Max VREF = 2496mV at 30°C, Min VREF = 2492mV at 0°C, VREF = 2495mV at 25°C, DTA = 70°C for TL431C.
| V REF | +
4mV Ǔ
ǒ2495mV
@ 10 6
70 oC
+ 23ppmń oC
Because minimum VREF occurs at the lower temperature, the coefficient is positive.
4. The dynamic impedance is defined as: | Z | + V KA
KA
I K
When the device is operating with two external resistors, (see Figure xx), the total dynamic impedance of the circuit is given by:
| ZȀ | + V [ | Z KA | 1 ) R1
R2
I
ǒ
Ǔ
PARAMETER MEASUREMENT INFORMATION
INPUT
VKA
INPUT
IK
VKA
Ioff
Vref
SL01177
SL01179
Figure 3. Test Circuit for VKA = Vref
INPUT
R1
R2
Figure 5. Test Circuit for IOFF
VKA
IK
Iref
Vref
V
KA
+V
ǒ1 ) R1
Ǔ ) Iref
R2
ref
R1
SL01178
Figure 4. Test Circuit for VKA > Vref
1997 Feb 25
5
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
3.0
VKA = Vref
IK = 10mA
2580
Iref – REFERENCE INPUT CURRENT – (µ A)
V ref – REFERENCE INPUT VOLTAGE – (mV)
2600
Vref = 2550mV
2560
2540
2520
Vref = 2495mV
2500
2480
2460
Vref = 2440mV
2440
2420
2400
–50
–25
0
25
50
75
100
125
R1 = 10kΩ
R2 = ∞
IK = 10mA
2.5
2.0
1.5
1.0
0.5
0
–75
–50
Tamb – TEMPERATURE – (°C)
–25
0
25
50
75
Tamb – TEMPERATURE – (°C)
100
SL01170
SL01168
Figure 9. Reference Input Current vs. Temperature
Ioff – OFF-STATE CATHODE CURRENT – (nA)
Figure 6. Reference Input Voltage vs. Temperature
150
VKA = Vref
Tamb = 25°C
CATHODE CURRENT – (mA)
125
100
75
50
25
0
–25
–50
–75
–100
–2
–1
0
1
2
125
3
90
VKA = 36V
Vref = 0V
80
70
60
50
40
30
20
10
0
–75
–50
–25
0
25
50
75
100
SL01169
SL01171
Figure 10. Off-State Cathode Current vs. Temperature
Figure 7. Cathode Current vs. Cathode Voltage
800
0
VKA = Vref
Tamb = 25°C
–0.1
600
VKA = 3V TO 36V
–0.2
Imin
d(Vref)/d(Vka) – (mV/V)
I K – CATHODE CURRENT – (µA)
125
Tamb – TEMPERATURE – (°C)
CATHODE VOLTAGE – (V)
400
200
0
–0.3
–0.4
–0.5
–0.6
–0.7
–0.8
–0.9
–200
–1
0
1
2
–1
3
–75
VKA – CATHODE VOLTAGE – (V)
–50
–25
0
25
50
75
100
SL01173
SL01172
Figure 8. Cathode Current vs. Cathode Voltage
1997 Feb 25
125
Tamb – TEMPERATURE – (°C)
Figure 11. Ratio of Delta Reference Voltage to
Delta Cathode Voltage over Temperature
6
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
4
Vn – INPUT NOISE VOLTAGE – µ V
3
2
1
0
–1
–2
–3
–4
0
1
2
3
4
5
6
t – TIME – (SECONDS)
7
8
9
10
Equivalent Input Noise Voltage Over a 10-Second Period
19.1V
1kΩ
500µF
910Ω
2000µF
VCC
VCC
1µF
TL431
(DUT)
TLE2027
AV = 10V/mV
820Ω
TLE2027
AV = 2V/V
16kΩ
22µF
16kΩ
16Ω
160kΩ
1µF
1MΩ
33kΩ
CRO
0.1µF
33kΩ
VEE
VEE
Test Circuit
SL01174
Figure 12.
400
IK = 10mA
Tamb = 25°C
Vn – NOISE VOLTAGE – nV/√ Hz
350
300
250
200
150
100
10
100
1K
f–FREQUENCY–Hz
10K
Figure 13. Equivalent Input Noise Voltage vs. Frequency
1997 Feb 25
7
100K
SL01180
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
TYPICAL CHARACTERISTICS
INPUT AND OUTPUT VOLTAGE – V
7
6
220Ω
OUTPUT
5
PULSE
GENERATOR
f = 100kHz
4
50Ω
3
GND
2
1
Test Circuit
0
0
1
2
3
4
5
6
7
t – TIME – µs
Pulse Response
SL01182
Figure 14. Pulse Response
100
90
IK – CATHODE CURRENT – (mA)
80
150Ω
Tamb = 25°C
A VKA = Vref
B VKA = 5V
C VKA = 10V
D VKA = 15V
UNSTABLE
VKA < 5
B
IK
VBATT
CL
70
UNSTABLE
VKA < 10
STABLE
STABLE
60
A
Test Circuit for Curve A
50
A
40
R1 = 10kΩ
30
150Ω
CL
20
R2
C
10
0
0.001
IK
VBATT
UNSTABLE VKA < 15V
D
0.01
UNSTABLE VKA
0.1
1
CL – LOAD CAPACITANCE – (µF)
10
Test Circuit for Curves B, C, and D
SL01176
Figure 15. Stability Boundary Conditions
1997 Feb 25
8
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
100
IK = 10mA
Tamb = 25°C
|ZKA| – REFERENCE IMPEDANCE – Ω
1kΩ
OUTPUT
10
IK
50Ω
GND
1
Test Circuit for Reference Impedance
0.1
1K
10K
100K
1M
10M
f – FREQUENCY – Hz
SL01175
Figure 16. Reference Impedance vs. Frequency
70
IK = 10mA
Tamb = 25°C
Av – VOLTAGE AMPLIFICATION – dB
60
OUTPUT
50
15kΩ
IK
230Ω
9µF
40
8.25kΩ
30
GND
20
Test Circuit for Voltage Amplification
10
0
1K
10K
100K
FREQUENCY IN Hz
1M
10M
SL01181
Figure 17. Small-Signal Voltage Amplification vs. Frequency
1997 Feb 25
9
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
TYPICAL APPLICATIONS
V+
V+
VOUT
VOUT
R1
R1
R2
R2
ǒ
ǒ
Ǔ
Ǔ
V OUT + 1 ) R1 V ref
R2
VOUT Min = Vref + Vbe
V OUT + 1 ) R1 V ref
R2
SL01183
Figure 18. Shunt Regulator
SL01186
Figure 21. Series Pass Regulator
V+
RCL
V+
IOUT
VOUT
VIN
VIN
VOUT
< Vref
V+
> Vref
≈2.0V
I OUT +
V ref
R CL
VTH = Vref
SL01187
SL01184
Figure 19. Single-Supply Comparator with
Temperature-Compensated Threshold
V+
Figure 22. Constant Current Source
V+
VOUT
ISINK
R1
I SINK +
V ref
RS
R2
RS
ǒ
Ǔ
V OUT + 1 ) R1 V ref
R2
SL01185
SL01189
Figure 20. High Current Shunt Regulator
1997 Feb 25
Figure 23. Constant Current Sink
10
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
SO8: plastic small outline package; 8 leads; body width 3.9mm
1997 Feb 25
11
SOT96-1
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
DIP8: plastic dual in-line package; 8 leads (300 mil)
1997 Feb 25
SOT97-1
12
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
SOT54
0.40
min.
4.2 max.
5.2 max.
12.7 min.
1.6
0.48
0.40
1
4.8
max.
2.54
2
3
0.66
0.56
2.0 max. (1)
Dimensions in mm.
(1) Terminal dimensions within this zone are uncontrolled to allow for flow of plastic and terminal irregularities.
SL01191
1997 Feb 25
13
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
TO-92 transistors on tape
TO-92
P
T
A1
∆h
(p)
∆h
A
H2
H1
W2
H0
W0 W
1
L
W
F1
F2
t1
D0
F
t
P2
P0
SL01192
Table 2. Tape specification (TO-92 leaded types)
SPECIFICATIONS
SYMBOL
DIMENSION
MIN.
NOM.
MAX.
TOL.
UNIT
–
4.8
–
mm
5.2
–
mm
A1
Body width
4
A
Body height
4.8
T
Body thickness
3.5
3.9
–
mm
P
Pitch of component
–
12.7
–
±1
mm
P0
Feed hole pitch
–
12.7
–
±0.3
mm
REMARKS
Cumulative pitch error
–
–
–
±0.1
mm
Note 1
P2
Feed hole center to component center
–
6.35
–
±0.4
mm
to be measured at bottom of clinch
F
Distance between outer leads
–
5.08
–
+0.6/–0.2
mm
∆h
Component alignment
–
0
1
–
mm
W
Tape width
–
18
–
±0.5
mm
W0
Hold-down tape width
–
6
–
±0.2
mm
W1
Hole position
–
9
–
+0.7/–0.5
mm
W2
Hold-down tape position
–
0.5
–
±0.2
mm
H0
Lead wire clinch height
–
16.5
–
±0.5
mm
H1
Component height
–
–
23.25
–
mm
L
Length of snipped leads
–
–
11
–
mm
D0
Feed hole diameter
–
4
–
±0.2
mm
t
Total tape thickness
–
–
1.2
–
mm
F1, F2
Lead-to-lead distance
–
–
–
+0.4/–0.2
mm
H2
Clinch height
–
–
–
–
mm
(p)
Pull-out force
6
–
–
–
N
NOTE:
1. Measured over 20 devices.
1997 Feb 25
14
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
Tape splicing
Bulk packing
Splice the carrier tape on the back and/or front so that the feed hole
pitch (P0) is maintained.
In addition to TO-92 on tape, TO-92 can also be delivered in bulk.
Products are packed in boxes in foil and plastic bags with 1,000
pieces to a bag and 5 bags to a box.
LABEL
LABEL
CARRIER STRIP
CARRIER STRIP
ROUNDED
SIDE
FLAT SIDE
ADHESIVE TAPE
ADHESIVE TAPE
ÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉ
CATHODE
PIN
FEED
FEED
FLAT SIDE OF TRANSISTOR AND ADHESIVE TAPE VISIBLE
ROUNDED SIDE OF TRANSISTOR AND ADHESIVE TAPE VISIBLE
SPC T (Note 1)
SPC F (Note 1)
VREF
PIN
SL01193
Figure 24. TO-92 Reel Styles
ÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉ
ADHESIVE TAPE ON TOP SIDE
FLAT SIDE
LABEL
FLAT SIDE OF TRANSISTOR
AND ADHESIVE TAPE VISIBLE
In Ammo Pack, the parts are put on the tape
the same as in SPC T. However, depending
on which end of the Ammo Pack is opened,
the VREF OR Cathode pin may come first. If
opened from the end marked with a “+”, the
Cathode comes first.
SPC A (Note 1)
Figure 25. TO-92 Ammo Pack Styles
NOTE:
1. Order SPC F, T or A depending on what is required.
1997 Feb 25
CARRIER STRIP
15
SL01194
Philips Semiconductors
Product specification
TL431C, TL431AC, TL431I,
TL431AI, LM431AC
Adjustable precision shunt regulators
DEFINITIONS
Data Sheet Identification
Product Status
Definition
Objective Specification
Formative or in Design
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
Preliminary Specification
Preproduction Product
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
Product Specification
Full Production
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICATIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
 Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
1997 Feb 25
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