LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Publication Order Number:
LM431SA/D
© 2004 Semiconductor Components Industries, LLC.
October-2017, Rev. 7
LM431SA / LM431SB / LM431SC
Programmable Shunt Regulator
Features
• Programmable Output Voltage to 36 V
• Low Dynamic Output Impedance: 0.2 Ω (Typical)
• Sink Current Capability: 1.0 to 100 mA
• Equivalent Full-Range Temperature Coefficient of
50 ppm/°C (Typical)
• Temperature Compensated for Operation Over
Full Rated Operating Temperature Range
• Low Output Noise Voltage
• Fast Turn-on Response
Ordering Information
Note:
1. SOT-23 and SOT-23F have basically four-character marking except LM431SAIMFX.
(3 letters for device code + 1 letter for date code)
SOT-23F date code is composed of 1 digit numeric or alphabetic week code adding bar-type year code.
> Week code: Change in every two weeks > Year code (additional bar): Rotate in three year cycle
Product Number Output V oltage
Tolerance Operating
Temperature Top Mark(1) Package Packing Method
LM431SACMFX 2%
-25 to +85°C
43A □SOT-23F 3L
Tape and Reel
LM431SACM3X 43L◎SOT-23 3L
LM431SACM32X 43G◎SOT-23 3L
LM431SBCMLX
1%
43B SOT-89 3L
LM431SBCMFX 43B □SOT-23F 3L
LM431SBCM3X 43M◎SOT-23 3L
LM431SBCM32X 43H◎SOT-23 3L
LM431SCCMLX
0.5%
43C SOT-89 3L
LM431SCCMFX 43C □SOT-23F 3L
LM431SCCM3X 43N◎SOT-23 3L
LM431SCCM32X 43J◎SOT-23 3L
LM431SAIMFX 2% -40 to +85°C 43AI SOT-23F 3L
1.Ref 2. Anode 3. Cathode
1
SOT-89 SOT-23F
12
3
1. Cathode 2. Ref 3. Anode
SOT-23
12
3
M32 - 1. Ref 2. Cathode 3. Anode
M3 - 1. Cathode 2. Ref 3. Anode
Week
Code
Week
Code
01~02 03~04 05~06 07~08 09~10 11~12 13~14 15~16 17~18 19~20 21~22 23~24 25~26
123456789ADEF
27~28 29~30 31~32 33~34 35~36 37~38 39~40 41~42 43~44 45~46 47~48 49~50 51~52
HJ KL NOPRSTUVX
Year
Code
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Description
The LM431SA / LM431SB / LM431SC are three-terminal
the output adju sta ble regu lators wit h thermal s ta bility o ver
operating temperature range. The output voltage can be
set any value between VREF (approximately 2.5 V) and
36 V with two external resistors. These devices have a
typical dynamic output impedance of 0.2 Ω. Active output
circuit provides a sharp turn-on characteristic, making
these devices excellent replacement for zener diodes in
many applications.
LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
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Block Diagram
Figure 1. Block Diagram
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be opera-
ble above the re co mmen ded operating co nd iti ons an d s tres si ng the part s to the se lev el s i s n ot re co mme nde d. In addi-
tion, extended exposure to stresses above the recommended operating conditions may affect device reliability. The
absolute maximum ratings are stress ratings only. Values are at TA = 25°C unless otherwise noted.
Notes:
2. Thermal resistance test board
Size: 1.6 mm x 76 .2 mm x 114.3 mm (1S0P)
JEDEC Standard: JESD51-3, JESD51-7.
3. Assume no ambient airflow.
4. TJMAX = 150°C; ratings apply to ambient temperature at 25°C.
5. Power dissipation calculation: PD = (TJ - TA) / RθJA.
Recommended Operating Conditions
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. ON does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol Parameter Value Unit
VKA Cathode Voltage 37 V
IKA Cathode current Range (Continuous) -100 to +150 mA
IREF Reference Input Current Range -0.05 to +10.00 mA
RθJA Thermal Resistance
Junction-Air (2,3)
ML Suffix Package (SOT-89) 220
°C/WMF Suffix Package (SOT-23F) 350
M32, M3 Suffix Package (SOT-2 3) 400
PDPower Dissipation (4,5) ML Suffix Package (SOT-89) 560 mWMF Suffix Package (SOT-23F) 350
M32, M3 Suffix Package (SOT-2 3) 310
TJJunction Temperature 150 °C
TOPR Operating Temperature
Range All products except LM431SAIMFX -25 to +85 °C
LM431SAIMFX -40 to +85
TSTG Storage Tem perature Rang e -65 to +150 °C
Symbol Parameter Min. Max. Unit
VKA Cathode Voltage VREF 36 V
IKA Cathode Current 1 100 mA
+
-
LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Electrical Characteristics(6)
Values are at TA = 25°C unless otherwise noted.
Note:
6. TMIN = -25°C, TMAX = +85°C.
Symbol Parameter Conditions LM431SA LM431SB LM431SC Unit
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max.
VREF Reference Input
Voltage VKA = VREF, IKA = 10 mA 2.450 2.500 2.550 2.470 2.495 2.520 2.48 2 2.495 2.5 08 V
Δ
VREF /
Δ
T
Deviation of
Reference
Input Voltage
Over-
Temperature
VKA = VREF,
IKA = 10 mA
TMIN ≤ TA ≤
TMAX
SOT-89
SOT-23F 4.5 17.0 4.5 17.0 4.5 17.0 mV
SOT-23 6.6 24 6.6 24 6.6 24 mV
Δ
VREF /
Δ
VKA
Ratio of Chan ge
in Reference
Input Voltage
to the Chang e in
Cathode Voltag e
IKA =10 mA
Δ
VKA =
10 V-VREF -1.0 -2.7 -1.0 -2.7 -1.0 -2.7
mV/V
Δ
VKA =
36 V-10 V -0.5 -2.0 -0.5 -2.0 -0.5 -2.0
IREF Reference Input
Current IKA = 10 mA,
R1 = 10 KΩ, R2 = ∞1.5 4.0 1.5 4.0 1.5 4.0 μA
Δ
IREF /
Δ
T
Deviation of
Reference
Input Curr ent
Over Full
Temperature
Range
IKA = 10 mA,
R1 = 10 KΩ,
R2 = ∞,
TA = Full
Range
SOT-89
SOT-23F 0.4 1.2 0.4 1.2 0.4 1.2 μA
SOT-23 0.8 2.0 0.8 2.0 0.8 2.0 μA
IKA(MIN)
Minimum
Cathode Current
for Regulation VKA = VREF 0.45 1.00 0.45 1.00 0.45 1.00 mA
IKA(OFF) Off -Stage
Cathode Current VKA = 36 V, VREF = 0 0.05 1.00 0.05 1.00 0.0 5 1.00 μA
ZKA Dynamic
Impedance
VKA = VREF,
IKA = 1 to 100 mA,
f ≥ 1.0 kHz 0.15 0.50 0.15 0.50 0.15 0.50 Ω
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Electrical Characteristics(7, 8) (Continued)
Values are at TA = 25°C unless otherwise noted.
Notes:
7. TMIN = -40°C, TMAX = +85°C.
8. The deviation parameters VREF(dev) and IREF(dev)are defined as the diff erences bet ween the maximum and minimum
values obtained over the rated temperature range. The average full-range temperature coefficient of the reference
input voltage, αVREF, is defined as:
where TMAX -TMIN is the rated operating free-air temperature range of the device.
αVREF can be positive or negative, depending on whether min imum VREF or maximum VREF, respectively, occurs at
the lower temperature.
Example: VREF(dev) = 4.5 mV, VREF = 2500 mV at 25 °C, TMAX -TMIN = 125 °C for LM431 SAI.
Because minimum VREF occurs at the lower temperature, the coefficient is positive.
Symbol Parameter Conditions LM431SAI Unit
Min. Typ. Max.
VREF Reference Input Voltage VKA = VREF, IKA = 10 mA 2.450 2.500 2.550 V
VREF(dev)
Deviation of Reference
Input Voltage Over-
Temperature
VKA = VREF, IKA = 10 mA,
TMIN ≤ TA ≤ TMAX 520mV
Δ
VREF/
Δ
VKA
Ratio of Change in
Reference Input Voltage
to Change in Cathode
Voltage
IKA = 10 mA
Δ
VKA = 10 V - VREF -1.0 -2.7
mV/V
Δ
VKA = 36 V - 10 V -0.5 -2.0
IREF Reference Input Current IKA = 10 mA, R1 =10 KΩ, R2 = ∞1.5 4.0 μA
IREF(dev)
Deviation of Reference
Input Current Over Full
Temperature Range
IKA = 10 mA, R1 = 10 KΩ, R2 = ∞,
TMIN ≤ TA ≤ TMAX 0.8 2.0 μA
IKA(MIN) Minimum Cathode
Current for Regulation VKA = VREF 0.45 1.00 mA
IKA(OFF) Off -Stage Cathode
Current VKA = 36 V, VREF = 0 0.05 1.00 μA
ZKA Dynamic Impedance VKA = VREF, IKA = 1 to 100 mA,
f ≥ 1.0 kHz 0.15 0.50 Ω
αVREF ppm
°C
------------
VREF dev()
VREF at25°C()
----------------------------------------
106
⋅
TMAX TMIN
–
------------------------------------------------------------
=
αVREF
4.5mV
2500mV
------------------------
106
⋅
125°C
-------------------------------------------- 14.4ppm °C⁄==
V
REF(min)
V
REF(max)
T
MAX
-T
MIN
V
REF(dev)
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Test Circuits
Figure 2. Test Circuit for VKA = VREF Figure 3. Test Circuit for VKA ≥ VREF
Figure 4. Test Circuit for lKA(OFF)
LM431S
LM431S
LM431S
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Typical Applications
Figure 5. Shunt Regulator Figure 6. Output Control for Three- Terminal Fixed
Regulator
Figure 7. High Current Shunt Regulator
Figure 8. Current Limit or Current Source Figure 9. Constant-Current Sink
VO1R1
R2
-------
+
Vref
=
LM431S
VOVref 1R1
R2
-------
+
=
LM431S
LM7805/MC7805
VO1R1
R2
-------
+
Vref
=
LM431S
LM431S
LM431S
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Typical Performance Characteristics
Figure 10. Cathode Current vs. Cathode Voltage Figure 11. Cathode Current vs. Cathode Voltage
Figure 12. OFF-State Cathode Current vs.
Ambient Temperature Figure 13. Reference Input Current vs.
Ambient Temperature
Figure 14. Frequency vs. Small Signal Voltage
Amplification Figure 15. Pulse Response
-2 -1 0 1 2 3
-100
-50
0
50
100
150
VKA = VREF
TA = 25oC
IK, Cathode Current ( m A)
VKA, Cathode Voltage (V)
IK - Cathode Current (mA)
VKA - Cathode Voltage (V)
-10123
-200
0
200
400
600
800
IKA(MIN)
VKA = VREF
TA = 25oC
IKA, CATHODE CURRENT (uA)
VKA, CATHODE VOLTAGE (V)
IKA - Cathode Current (μA)
VKA - Cathode Voltage (V)
-50 -25 0 25 50 75 100 125 150
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
Ioff, Off-State Cathode Current (uA)
TA, Am bient Temperature (oC)
Ioff - Off-State Cathode Curre n t (μA)
TA - Ambient Temperature (oC)
-50 -25 0 25 50 75 100 125
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Iref, Reference Input Current (uA)
TA, Ambient Temperature (oC)
TA - Ambient Temperature (oC)
Iref - Reference Input Current (μA)
1k 10k 100k 1M 10M
-10
0
10
20
30
40
50
60 TA = 25oC
IKA = 10mA
Open Loop Voltage Gain (dB)
Frequency (Hz)
Open Loop Voltage Gain (dB)
Frequency (Hz)
048121620
0
1
2
3
4
5
6
TA=25oC
OUTPUT
INPUT
Voltage Swing (V)
Time (us)
Time (μs)
Voltage Swing (V)
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Typical Performance Characteristics (Continued)
Figure 16. Stability Boundary Conditions Figure 17. Anode-Reference Diode Curve
Figure 18. Reference-Cathode Diode Curve Figure 19. Reference Input Voltage vs.
Ambient Temperature
100p 1n 10n 100n 1? 10?
0
20
40
60
80
100
120
140
B
A
A VKA = Vref
B VKA = 5.0 V @ IK = 10mA
TA = 25oC
IK, CATHODE CURRENT(mA)
CL, LOAD CAPACITANCE
IK - Cathode Current (mA)
CL - Load Capacitance
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0
1
2
3
4
5
Current(mA)
Anode-Ref. Voltage(V)
Current (mA)
Anode-Ref . Voltage (V)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0
1
2
3
4
5
Current(mA)
Ref.-Cathode Voltage(V)
Ref.-Cathode Voltag e (V)
Current (mA)
-50 -25 0 25 50 75 100 125
2.46
2.47
2.48
2.49
2.50
2.51
VREF , Reference Input Voltage (V)
TA, Ambient Temperature (oC)
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Physical Dimensions
Figure 20. 3-LEAD, SOT-89, JEDEC TO-243, OPTION AA
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Physical Dimensions (Continued)
Figure 21. 3-LEAD, SOT23F, FLAT LEAD, LOW PROFILE
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LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Physical Dimensions (Continued)
Figure 22. 3-LEAD, SOT-23, JEDEC TO-236, LOW PROFILE
LAND PATTERN
RECOMMENDATION
NOTES: UNLESS OTHERWISE SPECIFIED
A) REFERENCE JEDEC REGISTRATION
TO-236, VARIATION AB, ISSUE H.
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS ARE INCLUSIVE OF BURRS,
MOLD FLASH AND TIE BAR EXTRUSIONS.
D) DIMENSIONING AND TOLERANCING PER
ASME Y14.5M - 1994.
E) DRAWING FILE NAME: MA03DREV10
3
12
SEE DETAIL A
SEATING
PLANE
SCALE: 2X
GAGE PLANE
(0.55)
(0.93)
1.20 MAX
C
0.10
0.00
0.10 C
2.40±0.30
2.92±0.20
1.30+0.20
-0.15
0.60
0.37
0.20 A B
1.90
0.95
(0.29)
0.95
1.40
2.20
1.00
1.90
0.25
0.23
0.08
0.20 MIN
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