Description
The GS431B/TL431A/TL431 are 3-terminal adjustable
precision shunt regulators with guaranteed temperature
stability over the applicable extended commercial
temperature range. The output voltage may be set at any
level greater than 2.495V (VREF) up to 30V merely by
selecting two e xternal resistors that act as a voltage divider
network.These de vices hav e a typical output impedance of
0.08Ω. Active output circuitry provides very sharp turn-on
characteristics, making these devices excellent improved
replacements for zener diodes in many applications.
The precise ±0.5% reference voltage tolerance of the
GS431B makes it possible in many applications to avoid
the use of a variab le resistor , consequently saving cost and
eliminating drift and reliability problems associated with it.
Applications
• Voltage Monitor
• Delay Timer
• Constant-Current Source/Sink
• High-Current Shunt Regulator
• Crow Bar
• Over-Voltage/Under-Voltage Protection
Mechanical Data
Case: SO-8, SOT-23, SOT-89, TO-92
High temperature soldering guaranteed:
260°C/10 seconds at terminals
Case outlines are on the back pages
Features
• Programmable Output Voltage to 30V
• Precision Reference Voltage
GS431B: 2.495V ±0.5%
TL431A: 2.495V ±1.0%
TL431: 2.495V ±1.6%
• Sink Current Capability: 200mA.
• Minimum Cathode Current for Regulation: 250µA
• Equivalent Full-Range Temperature Coefficient:
50 ppm/ °C
• Fast Turn-On Response
• Low Dynamic Output Impedance: 0.08Ω
• Low Output Noise
TO-92
LP Suffix
U Suffix
SOT-23
S Suffix
SO-8
X Suffix
SOT-89
1
2
3
123
Symbol
Block Diagram
A
NODE (A)
REF (R)
CATHODE (C)
REF (R) +
-
ANODE (A)
CATHODE (C)
2.495V
1234
8765123
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
Preliminary
Adjustable Precision Shunt Regulators
Document Number 74806 www.vishay.com
1-Jul-02 1
Ordering Information
GS431BIxx
Package code
SO-8: S
TO-92: LP
SOT-89: X
SOT-23: U-1/U-2
U-1: Pin 1, Cathode
Pin 2, Vref
Pin 3, Anode
U-2: Pin 1, Vref
Pin 2, Cathode
Pin 3, Anode
Tolerance
Default: 1.6%
TL431xIxx A: 1.0%
Package code
SO-8: S
TO-92: LP
SOT-89: X
SOT-23: U-1/U-2
12
3
1
2
3
4
8
7
6
5
123
1
2
3
Top View
1. Cathode
2. Vref
3. Anode
Cathode
Anode
Anode
NC
Ref
Anode
Anode
NC
12
3
Top View
1. Vref
2. Cathode
3. Anode
Top View
1. Vref
2. Anode (tab)
3. Cathode
Top View
1. Vref
2. Anode
3. Cathode
Top View
SO-8SOT-23 (U-1)SOT-23 (U-2)SOT-89TO-92
Marking Information
SOT-23
GS431B, (U-1) DAxxxx*
TL431A, (U-1) DBxxxx
TL431, (U-1) DCxxxx
GS431B, (U-2) DDxxxx
TL431A, (U-2) DExxxx
TL431, (U-2) DGxxxx
*Last two digits denote datecode
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
www.vishay.com Document Number 74806
21-Jul-02
Electrical CharacteristicsTA= 25°C unless otherwise noted.
Parameter Symbol Test Conditions Min Typ Max Unit
VZ= VREF GS431B 2.482 2.495 2.508
IL= 10mA (Fig. 1) TL431A 2.470 2.495 2.520
Ref erence Voltage VREF TA= 25°CTL431 2.455 2.495 2.535 V
VZ= VREF GS431B 2.475 –2.520
IL= 10mA (Fig. 1) TL431A 2.445 –2.545
TA= –40°C to +85°CTL431 2.43 –2.56
Deviation of reference ∆VREF VZ= VREF TA= 0°C to 70°C–9.0 20 mV
Input voltage over temperature(1) IL= 10mA TA= –40°C to +85°C (Fig. 1) –15.0 50
Ratio of the change in reference voltage ∆VREF IZ= 10mA VZ= VREF ~ 10V –0.5 2.0 mV/V
to the change in cathode voltage ∆VZ(Fig. 2) VZ= 10V ~ 30V –0.35 1.5
Reference input current IREF R1 = 10KΩ, R2 = ∞TA= 25°C–0.8 3.5 µA
IL= 10mA (Fig. 2)
TA= –40°C to +85°C
––4.5
Deviation of reference input R1 = 10KΩ, R2 = ∞
current over temperature αIREF IL= 10mA –0.3 1.2 µA
TA= –40°C to +85°C (Fig. 2)
Minimum cathode current IZ(MIN) VZ= VREF (Fig. 1) –0.25 0.5 mA
for regulation
Off-state current IZ(OFF) VZ= 30V, VREF = 0V (Fig 3) –0.1 1.0 µA
Dynamic output impedance (2) RZVZ= VREF, f = 1.0KHZ –0.08 0.3 Ω
∆IZ = 1.0mA to 50mA
Absolute Maximum RatingsTA= 25°C unless otherwise noted.
Parameter Symbol Value Unit
Cathode voltage VZ30 V
Continuous cathode current IZ–10 to 250 mA
Reference Input Current Range IREF –0.05 to10 mA
Operating Temperature Range Toper –40 to 85 °C
Junction Temperature TJ150 °C
Lead Temperature TL260 °C
Storage Temperature Tstg –65 to 150 °C
Thermal Resistance TO-92 Package 115
SOT-23 Package RθJA 310 °C/W
SO-8 Package 163
SOT-89 Package 120
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
Document Number 74806 www.vishay.com
1-Jul-02 3
T2
TTEMPERATURE
1
VMAX
MIN
VDEV = VMAX MIN
-V
V
The average temperature coefficient of the reference
input voltage, αVREF is defined as:
T1T2
106
C)25(atV V
T1T2
106
C)25(atV V-V
C
ppm
VREF
DEV
REF
MINMAX
REF °
±
=
°
±
=
°
α––
Where:
T2– T1 = full temperature change.
The slope can be positive or negative depending on
whether VMAX or VMIN occurs at the lower ambient
temperature.
Example: ∆VREF = 9.0mV, VREF = 2495mV,
T2- T1 = 70°C, slope is positive.
C50ppm/
αVREF =C70
106
2495mV
9.0mV °=
°
Note 2. The dynamic output impedance, RZ, is
defined as:
When the device is programmed with two external
resistors, R1 and R2, (see Fig. 2), the dynamic output
impedance of the overall circuit, is defined as:
Z∆VZ
R =∆Z
I
R2
R1
1
≈ Rz
Iz
Vz
z
r+
∆
∆
=
Note 1. Deviation of reference input voltage, ∆VREF,
is defined as the maximum variation of the reference
input voltage over the full temperature range.
VREF
IREF IZ
VZ
IL
IN
R2
R1
VREF
IREF
IZ
VZ
IN IL
Note: VZ=VREF(1+R1/R2)+IREFxR1
IN
VZ
IZ(OFF)
fff C
Fig. 1 Test Circuit for VZ=VREF Fig. 2 Test Circuit for VZ>VREF Fig. 3 Test Circuit for
off-state current
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
www.vishay.com Document Number 74806
41-Jul-02
Document Number 74806 www.vishay.com
1-Jul-02 5
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
1.20
Fig. 6 – Reference Input Current
vs. Temperature
Reference Input Current (µA)
Temperature (°C)
-40 -20 0 20 40 60 80 100 120 --40 --20 0 20 40 60 80 100 120
R1=10KΩ
R2=
∞
IZ=10mA
IZ=10mA
TA=25°C
VZ = VREF
IZ = 1mA to 100mA
F ≤ 1KHZ
VZ=VREF
VZ=30V
0.28
0.24
0.20
0.16
0.12
0.08
0.04
0.00
Fig. 7 – Dynamic Impedance
vs. Temperature
Dynamic Impedance (Ω)
Temperature (°C)
510152025303540
Fig. 8 – Change in Reference Voltage
vs. Cathode Voltage
Change In Reference Voltage (mV)
Cathode Voltage (V)
--12
--10
--8
--6
--4
--2
0
0
2.5
2.0
1.5
1.0
0.5
0.0
--40 0 604020-20 80 100 120
Fig. 9 – Off-State Cathode Current
vs. Temperature
Off-State Cathode Current (µA)
Temperature (°C)
1000
800
600
400
200
0
-200
-400
-800
Fig. 4 – Cathode Current
vs. Cathode Voltage Fig. 5 – Reference Voltage
vs. Temperature
Cathode Current (µA)
2.58
2.56
2.54
2.52
2.50
2.48
2.46
2.44
2.42
2.40
Reference Voltage (V)
Cathode Voltage (V) Temperature (°C)
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -40 -20 0 20 40 60 80 100 120
V
Z
= V
REF
T
A
= 25°CTL431
V
Z
= V
REF
I
Z
= 10mA
I
Z(MIN)
V
REF
max
V
REF
typ
V
REF
min
Typical Performance
Characteristics
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
0→
1
2
3
2
4
6
0→
Fig. 12 – Pulse Response Fig. 13 – Test Circuit For Pulse
Fig. 15 – Test Circuit for Dynamic
1µS/div
0.1
1
10
1K 10K 100K 1M
Fig. 14 – Dynamic Impedance vs.
Dynamic Impedance (Ω) (V)
Frequency (Hz)
RA
50Ω
RB
220Ω
431
Output
Pulse
Generator
f=100kHz
R1
50
+
AC 1V
R2
50
431
GND
Output
I
Z
=10mA
T
A
=25°C
Input
Output
R1
10K R
250
+VIN
CIN
47
µ
F
V1
431
Output
I
Z
=10mA
T
A
=25°C
A
V
0
10
20
30
40
50
60
70
80
10 100 1k 10k 100k 1M 10M
Fig. 10 – Small Signal Voltage
Amplification vs. Frequency Fig. 11 – Test Circuit
Frequency Response
Small-Signal Voltage Amplification
Frequency (Hz)
--10
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
www.vishay.com Document Number 74806
61-Jul-02
Fig. 17 – Delay Timer
Fig. 18 – V oltage Monitor
Fig. 16 – Typical Application Circuit
Fig. 20 – Current Limiter or
Current Source
Fig. 19 – Constant-Current Sink
VIN
R1A
R2A
R1B
R2B
R
ON
OFF C
VIN
+
n ( V
VV
IN
IN REF )
R1IOUT
VIN
R
VIN
1
IOUT
IOUT=VREF / R1
IOUT=VREF / R1
LED on when Low Limit<VIN< High Limit
Low Limit ≅ VREF (1+R1B/R2B)
High Limit ≅ VREF (1+R1A/R2A)
Delay=R x C x
VIN
431
+
VOUT
R1
R2
+
Precision Regulator
VOUT = (1+R1/R2) x VREF
Application Examples
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
Document Number 74806 www.vishay.com
1-Jul-02 7
VOUT
R1
R2
VIN VIN R1
R2
VOUT
FUSE
R1A
R2A R2B
R1B
VIN
Out put ON when
Low Limit <VIN < High Limit
+
VBE
Fig. 23 – Over-Voltage / Under-Voltage
Protection Circuit
Fig. 21 – High-Current
Shunt Regulator Fig. 22 – Crow Bar
Low Limit ≅ VREF (1+R1B/R2B) + VBE
High Limit ≅ VREF (1+R1A/R2A)
VOUT = (1+R1/R2) x VREF VLIMIT = (1+R1/R2) x VREF
Application Examples
(continued)
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
www.vishay.com Document Number 74806
81-Jul-02
5
1234
6.20
5.80
876
4.00
3.80
0.51
0.33
1.27 (typ.)
0.25
0.10
5.00
4.80
1.75
1.35
1.27
0.40
0.25
0.19
SO-8 Case Outline
Dimensions
in millimeters
0.10
12
3Top View
3.10
2.70
3.00
2.60
1.80
1.40
0.90
0.70
1.90
(TYP.)
0.25
0.10
0.50
0.35
1.30
1.00
0.37
θ1 9°
1°
SOT-23 Case Outline
Dimensions
in millimeters
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
Document Number 74806 www.vishay.com
1-Jul-02 9
TO-92 Case Outline
Dimensions
in millimeters
5.33
4.32
1.27 (TYP.)
Bottom
View
12.7
0.38 (TYP.)
5.20
4.40 4.20
3.17
SOT-89 Case Outline
1.83
1.62
1.60
1.40
4.60
4.40
Top View
4.25
3.94
2.60
2.29
1.20
0.89
3.00
(TYP.)
1.50
(TYP.) 0.48
0.36 0.44
0.35
123
Dimensions
in millimeters
GS431B/TL431A/TL431
Vishay
for merly General Semiconductor
www.vishay.com Document Number 74806
10 1-Jul-02
