1. General description
Three-terminal shu nt regulator fa mily with an outpu t volt age range b etween V ref and 36 V,
to be set by two external resistors.
The TL431xDBZR types feature an enhanced stability area with a very low
load capacity requirement.
The TL431xFDT types offer an enhanced stability area and a higher
ElectroMagnetic Interference (EMI) ruggedn ess, for example, for Switch Mode Power
Supply (SMPS) applications.
The TL431xSDT types are designed for standard requirements and linear
applications.
TL431 family
Adjustable precision shunt regulator
Rev. 4 — 30 June 2011 Product data sheet
SOT23
Table 1. Product overview
Reference voltage
tolerance (Vref)Temperature range (Tamb)Pinning
configuration
(see Table 5)
0 to 70 C40 to 85 C40 to 125 C
2 % TL431CDBZR TL431IDBZR TL431QDBZR normal pinning
TL431FDT normal pinning
TL431MFDT mirrored pinning
TL431SDT normal pinning
TL431MSDT mirrored pinning
1 % TL431ACDBZR TL431AIDBZR TL431AQDBZR normal pinning
TL431AFDT normal pinning
TL431AMFDT mirrored pinning
TL431ASDT normal pinning
TL431AMSDT mirrored pinning
0.5 % TL431BCDBZR TL431BIDBZR TL431BQDBZR normal pinning
TL431BFDT normal pinning
TL431BMFDT mirrored pinning
TL431BSDT normal pinning
TL431BMSDT mirrored pinning
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Product data sheet Rev. 4 — 30 June 2011 2 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
2. Features and benefits
Programmable output voltage up to 36 V
Three different reference voltage tolerances:
Standard grade: 2 %
A-Grade: 1 %
B-Grade: 0.5 %
Typical temperature drift: 6 mV (in a range of 0 C up to 70 C)
Low output nois e
Typical output impedance: 0.2
Sink current capability: 1 mA to 100 mA
AEC-Q100 qualified (grade 1)
3. Applications
Shunt regulator
Precision current limiter
Precision constant current sink
Isolated feedback loop for Switch Mode Power Supply (SMPS)
4. Quick reference data
Table 2. Quick reference data
Symbol Parameter Conditions Min Typ Max Unit
VKA cathode-anode voltage Vref -36V
IKcathode current 1 - 100 mA
Vref reference voltage VKA =V
ref;
IK=10mA;
Tamb =25C
Standard-Grade (2 %) 2440 2495 2550 mV
A-Grade (1 %) 2470 2495 2520 mV
B-Grade (0.5 %) 2483 2495 2507 mV
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Product data sheet Rev. 4 — 30 June 2011 3 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
5. Ordering information
Table 3. Ordering information
Type number Package
Name Description Version
TL431CDBZR - plastic surface-mounted package; 3 leads SOT23
TL431IDBZR
TL431QDBZR
TL431FDT
TL431MFDT
TL431SDT
TL431MSDT
TL431ACDBZR
TL431AIDBZR
TL431AQDBZR
TL431AFDT
TL431AMFDT
TL431ASDT
TL431AMSDT
TL431BCDBZR
TL431BIDBZR
TL431BQDBZR
TL431BFDT
TL431BMFDT
TL431BSDT
TL431BMSDT
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Product data sheet Rev. 4 — 30 June 2011 4 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
6. Marking
[1] * = placeholder for manufacturing site code.
7. Functional diagram
The TL431 family comprises a range of 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 2.5 V)
and 36 V with two external resistors (see Figure 8). These devices have a typical output
impedance of 0.2 . Active output circuitry provides a very shar p tur n -o n ch aracteristic,
making these devices excellent replacement s for Zener diodes in many applications like
on-board regulation, adjustable power supplies and switching power supplies.
Table 4. Marking codes
Type number Marking code[1] Type number Marking code[1]
TL431CDBZR CA* TL431ASDT RL*
TL431IDBZR CB* TL431AMSDT LQ*
TL431QDBZR CC* TL431BCDBZR CG*
TL431FDT AR* TL431BIDBZR CH*
TL431MFDT AU* TL431BQDBZR CJ*
TL431SDT RM* TL431BFDT AT*
TL431MSDT LR* TL431BMFDT AW*
TL431ACDBZR CD* TL431BSDT MA*
TL431AIDBZR CE* TL431BMSDT MB*
TL431AQDBZR CF* - -
TL431AFDT AS* - -
TL431AMFDT AV* - -
Fig 1. Functional diagram
Vref
ANODE
CATHODE
REF
006aab569
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Product data sheet Rev. 4 — 30 June 2011 5 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
8. Pinning information
9. Limiting values
[1] Device mounted on an FR4 Printed-Circuit Board (PCB), single-sided copper, tin-plated and standard
footprint.
[2] Device mounted on an FR4 PCB, single-sided copper, tin-plated, mounting pad for anode 1 cm2.
[3] Device mounted on a ceramic PCB, Al2O3, standard footprint.
Table 5. Pinning
Pin Symbol Description Simplified outline Graphic symbol
Normal pinning: All types wit ho ut MFDT and MSDT ending
1 k cathode
2 REF reference
3 a anode
Mirrored pinnin g: All types with MFDT and MSDT ending
1 REF reference
2 k cathode
3 a anode
12
3
006aab355
REF
ak
12
3
006aab355
REF
ak
Table 6. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter Conditions Min Max Unit
VKA cathode-anode voltage - 37 V
IKcathode current 100 150 mA
Iref reference current 0.05 10 mA
Ptot total power dissipation Tamb 25 C[1] -350mW
[2] -580mW
[3] -950mW
Tjjunction temperature - 150 C
Tamb ambient temperature
TL431XCDBZR 0 +70 C
TL431XIDBZR 40 +85 C
TL431XQDBZR
TL431XFDT
TL431XSDT
40 +125 C
Tstg storage temperature 65 +150 C
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Product data sheet Rev. 4 — 30 June 2011 6 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
10. Recommended operating conditions
(1) Ceramic PCB, Al2O3, standard footprint
(2) FR4 PCB, mounting pad for anode 1 cm2
(3) FR4 PCB, standard footprint
Fig 2. Power derating curves
Table 7. ESD maximum ratings
Tamb =25
C unless otherwise specified.
Symbol Parameter Conditions Min Max Unit
VESD electrostatic discharge voltage MIL-STD-883
(human body model) -4kV
Tamb (°C)
75 17512525 7525
006aab570
500
750
250
1000
1250
Ptot
(mW)
0
(1)
(2)
(3)
Table 8. Operating cond itions
Symbol Parameter Conditions Min Max Unit
VKA cathode-anode voltage Vref 36 V
IKcathode current 1 100 mA
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Product data sheet Rev. 4 — 30 June 2011 7 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
11. Thermal characteristics
[1] Device mounted on an FR4 PCB, single-sided copper, tin-plated and standard footprint.
[2] Device mounted on an FR4 PCB, single-sided copper, tin-plated, mounting pad for anode 1 cm2.
[3] Device mounted on a ceramic PCB, Al2O3, standard footprint.
[4] Soldering point of anode.
12. Characteristics
Table 9. Thermal characteristics
Symbol Parameter Conditions Min Typ Max Unit
Rth(j-a) thermal resistance from
junction to ambient in free air [1] --360K/W
[2] --216K/W
[3] --132K/W
Rth(j-sp) thermal resistance from
junction to solder point [4] --50K/W
Table 10. Characteristics
Tamb =25
C unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Unit
Standard-Grade (2 %):
TL431CDBZR; TL43 1IDBZR; TL431QDBZR; TL431FDT; TL43 1MFDT; TL431SDT; TL431MSDT
Vref reference voltage VKA =V
ref; IK= 10 mA 2440 2495 2550 mV
Vref reference voltage variation VKA =V
ref; IK=10mA
TL431CDBZR Tamb =0Cto70C-616mV
TL431IDBZR Tamb =40 Cto85C - 14 34 mV
TL431QDBZR
TL431FDT
TL431MFDT
TL431SDT
TL431MSDT
Tamb =40 C to 125 C
Vref/VKA reference voltage variation
to cathode-anode voltage
variation ratio
IK=10mA
VKA =10VtoV
ref -1.4 2.7 mV/V
VKA =36Vto10V - 12mV/V
Iref reference current IK=10mA;
R1 = 10 k; R2 = open -24A
Iref reference current variation IK=10mA;
R1 = 10 k; R2 = open
TL431CDBZR Tamb =0Cto70C-0.41.2A
TL431IDBZR Tamb =40 Cto85C- 0.82.5A
TL431QDBZR
TL431FDT
TL431MFDT
TL431SDT
TL431MSDT
Tamb =40 C to 125 C
IK(min) minimum cathode current VKA =V
ref -0.41mA
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Product data sheet Rev. 4 — 30 June 2011 8 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Ioff off-state current VKA =36V; V
ref =0 - 0.1 1 A
ZKA dynamic cathode-anode
impedance IK=1mAto100mA;
VKA =V
ref; f < 1 kHz -0.20.5
A-Grade(1%):
TL431ACDBZR; TL431AIDBZR; TL431AQDBZR; TL431AFDT; TL431AMFDT; TL431ASDT; TL431AMSDT
Vref reference voltage VKA =V
ref; IK= 10 mA 2470 2495 2520 mV
Vref reference voltage variation VKA =V
ref; IK=10mA
TL431ACDBZR Tamb =0Cto70C-616mV
TL431AIDBZR Tamb =40 Cto85C - 14 34 mV
TL431AQDBZR
TL431AFDT
TL431AMFDT
TL431ASDT
TL431AMSDT
Tamb =40 C to 125 C
Vref/VKA reference voltage variation
to cathode-anode voltage
variation ratio
IK=10mA
VKA =10VtoV
ref -1.4 2.7 mV/V
VKA =36Vto10V - 12mV/V
Iref reference current IK=10mA;
R1 = 10 k; R2 = open -24A
Iref reference current variation IK=10mA;
R1 = 10 k; R2 = open
TL431ACDBZR Tamb =0Cto70C-0.41.2A
TL431AIDBZR Tamb =40 Cto85C- 0.82.5A
TL431AQDBZR
TL431AFDT
TL431AMFDT
TL431ASDT
TL431AMSDT
Tamb =40 C to 125 C
IK(min) minimum cathode current VKA =V
ref
TL431ACDBZR Tamb =0Cto70C-0.40.6mA
TL431AIDBZR Tamb =40 Cto85C
TL431AQDBZR
TL431AFDT
TL431AMFDT
TL431ASDT
TL431AMSDT
Tamb =40 C to 125 C
Ioff off-state current VKA =36V; V
ref =0 - 0.1 0.5 A
ZKA dynamic cathode-anode
impedance IK=1mAto100mA;
VKA =V
ref; f < 1 kHz -0.20.5
Table 10. Characteristics …continued
Tamb =25
C unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Unit
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Product data sheet Rev. 4 — 30 June 2011 9 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
B-Grade(0.5%):
TL431BCDBZR; TL431BIDBZR; TL431BQDBZR; TL431BFDT; TL431BMFDT; TL431BSDT; TL431BMSDT
Vref reference voltage VKA =V
ref; IK= 10 mA 2483 2495 2507 mV
Vref reference voltage variation VKA =V
ref; IK=10mA
TL431BCDBZR Tamb =0Cto70C-616mV
TL431BIDBZR Tamb =40 Cto85C - 14 34 mV
TL431BQDBZR
TL431BFDT
TL431BMFDT
TL431BSDT
TL431BMSDT
Tamb =40 C to 125 C
Vref/VKA reference voltage variation
to cathode-anode voltage
variation ratio
IK=10mA
VKA =10VtoV
ref -1.4 2.7 mV/V
VKA =36Vto10V - 12mV/V
Iref reference current IK=10mA;
R1 = 10 k; R2 = open -24A
Iref reference current variation IK=10mA;
R1 = 10 k; R2 = open
TL431BCDBZR Tamb =0Cto70C-0.41.2A
TL431BIDBZR Tamb =40 Cto85C- 0.82.5A
TL431BQDBZR
TL431BFDT
TL431BMFDT
TL431BSDT
TL431BMSDT
Tamb =40 C to 125 C
IK(min) minimum cathode current VKA =V
ref
TL431BCDBZR Tamb =0Cto70C-0.40.6mA
TL431BIDBZR Tamb =40 Cto85C
TL431BQDBZR
TL431BFDT
TL431BMFDT
TL431BSDT
TL431BMSDT
Tamb =40 C to 125 C
Ioff off-state current VKA =36V; V
ref =0 - 0.1 0.5 A
ZKA dynamic cathode-anode
impedance IK=1mAto100mA;
VKA =V
ref; f < 1 kHz -0.20.5
Table 10. Characteristics …continued
Tamb =25
C unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Unit
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Product data sheet Rev. 4 — 30 June 2011 10 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
IK=10mA; V
KA =V
ref VKA =V
ref; Tamb =25C
Fig 3. Reference voltage as a function of ambient
temperature; typical values Fig 4. Cathode current as a function of
cathode-anode voltage; typical value s
IK=10mA; V
KA =V
ref
Fig 5. Test circuit to Figure 3 and Figure 4
Tamb (°C)
75 1257525 25
006aab571
2.48
2.52
2.44
2.56
2.60
Vref
(V)
2.40
VKA (V)
232011
006aab572
0
50
50
100
150
IK
(mA)
100
006aab573
GND
Vref
VKA
INPUT
IK
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Product data sheet Rev. 4 — 30 June 2011 11 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
IK=10mA; R1=10k; R2 = open IK=10mA; T
amb =25C
Fig 6. Reference current as a function of ambient
temperature; typical values Fig 7. Re feren ce voltage variation as a function of
cathode-anode voltage; typical value s
Fig 8. Test circuit to Figure 6 and Figure 7
Tamb (°C)
75 1257525 25
006aab574
2.0
3.0
1.0
4.0
5.0
Iref
(μA)
0.0
VKA (V)
0403010 20
006aab575
40
20
0
ΔVref
(mV)
60
006aab576
GND
Vref
VKA
INPUT
IK
Iref
R1
R2
VKA Vref 1R1
R2
-------
+


Iref R1+=
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Product data sheet Rev. 4 — 30 June 2011 12 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
VKA =36V; V
ref =0V
Fig 9. Off-state current as a function of ambient temperature; typical values
VKA =36V; V
ref =0V
Fig 10. Off-state current as a function of ambient temperature; test circuit
Tamb (°C)
75 1257525 25
006aab577
100
150
50
200
250
Ioff
(nA)
0
006aab578
GND
VKA
INPUT
Ioff
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Product data sheet Rev. 4 — 30 June 2011 13 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Tamb =25C
(1) Input
(2) Output
Tamb =25C
(1) Input
(2) Output
Fig 11. All types except TL431XFDT and TL431XSDT:
Input voltage and output voltage as a function
of time; typical values
Fig 12. TL431XFDT:
Input voltage and output voltage as a function
of time; typical values
Tamb =25C
(1) Input
(2) Output
Tamb =25C
Fig 13. TL431XSDT:
Input voltage and output voltage as a function
of time; typical values
Fig 14. Test circu it to Figure 11, Figure 12 and
Figure 13
t (μs)
17513
006aab579
2
4
6
Vin; Vout
(V)
0
(1)
(2)
t (μs)
17513
006aac478
2
4
6
Vin; Vout
(V)
0
(1)
(2)
t (μs)
17513
006aab580
2
4
6
Vin; Vout
(V)
0
(1)
(2)
006aab581
GND
VKA
220 Ω
50 Ω
PULSE
GENERATOR
f = 100 kHz
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Product data sheet Rev. 4 — 30 June 2011 14 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
IK=10mA; T
amb =25CI
K=10mA; T
amb =25C
Fig 15. All types except TL431XFDT and TL431XSDT:
Volt age amplification as a function of
frequency; typical values
Fig 16. TL431XFDT:
Voltage amplification as a function of
frequency; typical values
IK=10mA; T
amb =25CI
K=10mA; T
amb =25C
Fig 17. TL431XSDT:
Volt age amplification as a function of
frequency; typical values
Fig 18. Test circu it to Figure 15, Figure 16 and
Figure 17
006aab583
20
40
60
Av
(dB)
0
f (kHz)
110
4
103
10 102
006aac479
20
40
60
Av
(dB)
0
f (kHz)
110
4
103
10 102
006aab582
20
40
60
Av
(dB)
0
f (kHz)
110
4
103
10 102
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Product data sheet Rev. 4 — 30 June 2011 15 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
IK=10mA; T
amb =25CI
K=10mA; T
amb =25C
Fig 19. All types except TL431XFDT and TL431XSDT:
Dynamic cathode-anode impedance as a
function of frequency; typical values
Fig 20. TL431XFDT:
Dynamic cathode-anode impedance as a
function of frequency; typical values
IK=10mA; T
amb =25CI
K=10mA; T
amb =25C
Fig 21. TL431XSDT:
Dynamic cathode-anode impedance as a
function of frequency; typical values
Fig 22. Test circu it to Figure 19, Figure 20 and
Figure 21
006aab585
10
1
102
ZKA
(Ω)
101
f (kHz)
110
4
103
10 102
006aac480
10
1
102
ZKA
(Ω)
101
f (kHz)
110
4
103
10 102
006aab586
10
1
102
ZKA
(Ω)
101
f (kHz)
110
4
103
10 102
006aab587
GND
V
KA
I
K
50 Ω
1 kΩ
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Product data sheet Rev. 4 — 30 June 2011 16 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Tamb =25C
(1) VKA =V
ref
VKA = 5 V: no oscillation
VKA = 10 V: no oscillation
VKA = 15 V: no oscillation
Fig 23. All types except TL431XFDT and TL431XSDT:
Cathode current as a function of load capacitance; typical values
VKA =V
ref
Tamb =25CVKA > 5 V: stable operation
Tamb =25C
Fig 24. Test circuit (1) to Figure 23 Fig 25. Test circui t (2) to Figure 23
006aab588
40
60
20
80
100
I
K
(mA)
0
C
L
(nF)
1 10
4
10
3
10 10
2
Stable Oscillation Stable
(1) (1)
006aab589
GND
CL
I
K
150 Ω
VBATT
006aab590
GND
CL
IK150 Ω
VBATT
R2
R1 = 10 kΩ
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Product data sheet Rev. 4 — 30 June 2011 17 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Tamb =25C
(1) VKA =V
ref
VKA = 5 V: no oscillation
VKA = 10 V: no oscillation
VKA = 15 V: no oscillation
Fig 26. TL431XFDT: Cathode current as a function of load capacitance; typical values
VKA =V
ref
Tamb =25CVKA > 5 V: stable operation
Tamb =25C
Fig 27. Test circuit (1) to Figure 26 Fig 28. Test circui t (2) to Figure 26
006aac481
40
60
20
80
100
I
K
(mA)
0
10
1
C
L
(nF)
10
3
10
4
10
2
110
Stable Oscillation Stable
(1) (1)
006aab589
GND
CL
I
K
150 Ω
VBATT
006aab590
GND
CL
IK150 Ω
VBATT
R2
R1 = 10 kΩ
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Product data sheet Rev. 4 — 30 June 2011 18 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Tamb =25C
(1) VKA =V
ref
(2) VKA =5V
VKA = 10 V: no oscillation
VKA = 15 V: no oscillation
Fig 29. TL431XSDT: Cathode current as a function of load capacitance; typical values
VKA =V
ref
Tamb =25CVKA =5V
VKA > 10 V: stable operation
Tamb =25C
Fig 30. Test circuit (1) to Figure 29 Fig 31. Test circui t (2) to Figure 29
006aab591
40
60
20
80
100
I
K
(mA)
0
10
1
C
L
(nF)
10
3
10
4
10
2
110
Stable Oscillation Stable
(2) (2)
(1) (1)
006aab589
GND
CL
I
K
150 Ω
VBATT
006aab590
GND
CL
IK150 Ω
VBATT
R2
R1 = 10 kΩ
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Product data sheet Rev. 4 — 30 June 2011 19 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
13. Application information
Fig 32. Shunt regulator
;
Fig 33. Series pass regulator
Fig 34. Single-supply comparator with temperature-compensated threshold
006aab592
V
OUT
R1
R2
V+
VOUT 1R1
R2
-------
+


Vref
=
006aab593
VOUT
R1
R2
V+
VOUT 1R1
R2
-------
+


Vref
=
VOUT min Vref Vbe
+=
006aab594
VOUT
V+
VIN
Vth Vref
=
VIN Vref VOUT 0
VIN Vref VOUT 2V
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Product data sheet Rev. 4 — 30 June 2011 20 of 27
NXP Semiconductors TL431 family
Adjustable precision shunt regulator
Fig 35. Const ant current source
Fig 36. High-current sh un t regu la tor
Fig 37. Constant current sink
006aab595
I
OUT
RCL
V+
IOUT Vref
RCL
---------
=
006aab596
VOUT
R1
R2
V+
VOUT 1R1
R2
-------
+


Vref
=
006aab597
ISINK
RS