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TL431, TL432
SLVS543P – AUGUST 2004 – REVISED NOVEMBER 2018
TL431 / TL432 Precision Programmable Reference
1 Features
3 Description
•
The TL431LI / TL432LI are pin-to-pin alternatives
to TL431 / TL432. TL43xLI offers better stability,
lower temperature drift (VI(dev)), and lower
reference current (Iref) for improved system
accuracy.
1
•
•
•
•
•
•
Reference Voltage Tolerance at 25°C
– 0.5% (B Grade)
– 1% (A Grade)
– 2% (Standard Grade)
Adjustable Output Voltage: Vref to 36 V
Operation From −40°C to 125°C
Typical Temperature Drift (TL43xB)
– 6 mV (C Temp)
– 14 mV (I Temp, Q Temp)
Low Output Noise
0.2-Ω Typical Output Impedance
Sink-Current Capability: 1 mA to 100 mA
2 Applications
•
•
•
•
•
Adjustable Voltage and Current Referencing
Secondary Side Regulation in Flyback SMPSs
Zener Replacement
Voltage Monitoring
Comparator with Integrated Reference
Simplified Schematic
VKA
Input
IKA
The TL431 and TL432 devices are three-terminal
adjustable shunt regulators, with specified thermal
stability over applicable automotive, commercial, and
military temperature ranges. The output voltage can
be set to any value between Vref (approximately
2.5 V) and 36 V, with two external resistors. These
devices have a typical output impedance of 0.2 Ω.
Active output circuitry provides a very sharp turn-on
characteristic, making these devices excellent
replacements for Zener diodes in many applications,
such as onboard regulation, adjustable power
supplies, and switching power supplies. The TL432
device has exactly the same functionality and
electrical specifications as the TL431 device, but has
different pinouts for the DBV, DBZ, and PK packages.
Both the TL431 and TL432 devices are offered in
three grades, with initial tolerances (at 25°C) of 0.5%,
1%, and 2%, for the B, A, and standard grade,
respectively. In addition, low output drift versus
temperature ensures good stability over the entire
temperature range.
The TL43xxC devices are characterized for operation
from 0°C to 70°C, the TL43xxI devices are
characterized for operation from –40°C to 85°C, and
the TL43xxQ devices are characterized for operation
from –40°C to 125°C.
Vref
Device Information(1)
PART NUMBER
TL43x
PACKAGE (PIN)
BODY SIZE (NOM)
SOT-23-3 (3)
2.90 mm × 1.30 mm
SOT-23-5 (5)
2.90 mm × 1.60 mm
SOIC (8)
4.90 mm × 3.90 mm
PDIP (8)
9.50 mm × 6.35 mm
SOP (8)
6.20 mm × 5.30 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
TL431, TL432
SLVS543P – AUGUST 2004 – REVISED NOVEMBER 2018
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.10
7.11
7.12
7.13
7.14
8
1
1
1
2
3
4
5
Absolute Maximum Ratings ...................................... 5
ESD Ratings.............................................................. 5
Thermal Information .................................................. 5
Recommended Operating Conditions....................... 5
Electrical Characteristics, TL431C, TL432C ............. 6
Electrical Characteristics, TL431I, TL432I ................ 7
Electrical Characteristics, TL431Q, TL432Q............. 8
Electrical Characteristics, TL431AC, TL432AC ........ 9
Electrical Characteristics, TL431AI, TL432AI ......... 10
Electrical Characteristics, TL431AQ, TL432AQ.... 11
Electrical Characteristics, TL431BC, TL432BC .... 12
Electrical Characteristics, TL431BI, TL432BI ....... 13
Electrical Characteristics, TL431BQ, TL432BQ.... 14
Typical Characteristics .......................................... 15
Parameter Measurement Information ................ 19
9
Detailed Description ............................................ 20
9.1
9.2
9.3
9.4
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
20
20
21
21
10 Applications and Implementation...................... 22
10.1 Application Information.......................................... 22
10.2 Typical Applications .............................................. 22
10.3 System Examples ................................................. 27
11 Power Supply Recommendations ..................... 30
12 Layout................................................................... 30
12.1 Layout Guidelines ................................................. 30
12.2 Layout Example .................................................... 30
13 Device and Documentation Support ................. 31
13.1
13.2
13.3
13.4
13.5
13.6
13.7
Device Nomenclature............................................
Related Links ........................................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
31
31
31
31
31
32
32
14 Mechanical, Packaging, and Orderable
Information ........................................................... 32
4 Revision History
Changes from Revision O (January 2015) to Revision P
Page
•
Added text to the Description section..................................................................................................................................... 1
•
Added TL43x Device Comparison Table ............................................................................................................................... 3
•
Added TL43x Device Nomenclature section ........................................................................................................................ 31
Changes from Revision N (January 2014) to Revision O
Page
•
Added Applications, Device Information table, Pin Functions table, ESD Ratings table, Thermal Information table,
Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply
Recommendations section, Layout section, Device and Documentation Support section, and Mechanical,
Packaging, and Orderable Information section. ..................................................................................................................... 1
•
Added Applications. ................................................................................................................................................................ 1
•
Moved Typical Characteristics into Specifications section. ................................................................................................. 15
Changes from Revision M (July 2012) to Revision N
Page
•
Updated document formatting ................................................................................................................................................ 1
•
Removed Ordering Information table. .................................................................................................................................... 4
•
Added Application Note links................................................................................................................................................ 22
2
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SLVS543P – AUGUST 2004 – REVISED NOVEMBER 2018
5 Device Comparison Table
DEVICE PINOUT
INITIAL ACCURACY
OPERATING FREE-AIR TEMPERATURE (TA)
TL431
TL432
B: 0.5%
A: 1%
(Blank): 2%
C: 0°C to 70°C
I: -40°C to 85°C
Q: -40°C to 125°C
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TL431, TL432
SLVS543P – AUGUST 2004 – REVISED NOVEMBER 2018
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6 Pin Configuration and Functions
TL431, TL431A, TL431B . . . LP (TO-92/TO-226) PACKAGE
(TOP VIEW)
TL431A, TL431B . . . DCK (SC-70) PACKAGE
(TOP VIEW)
TL431 . . . KTP (PowerFLEX /TO-252) PACKAGE
(TOP VIEW)
CATHODE
ANODE
CATHODE
ANODE
CATHODE
NC
REF
ANODE
REF
REF
1
8
2
7
3
6
4
5
REF
ANODE
ANODE
NC
CATHODE
NC
NC
NC
3
4
ANODE
NC
NC
1
8
2
7
3
6
4
5
REF
NC
ANODE
NC
NC − No internal connection
TL431, TL431A, TL431B . . . PK (SOT-89) PACKAGE
(TOP VIEW)
TL432, TL432A, TL432B . . . PK (SOT-89) PACKAGE
(TOP VIEW)
REF
ANODE
ANODE
CATHODE
ANODE
ANODE
REF
CATHODE
TL432, TL432A, TL432B . . . DBV (SOT-23-5) PACKAGE
(TOP VIEW)
TL431, TL431A, TL431B . . . DBV (SOT-23-5) PACKAGE
(TOP VIEW)
NC
1
†
2
CATHODE
3
5
ANODE
4
REF
NC
1
ANODE
2
NC
3
REF
4
CATHODE
TL432, TL432A, TL432B . . . DBZ (SOT-23-3) PACKAGE
(TOP VIEW)
TL431, TL431A, TL431B . . . DBZ (SOT-23-3) PACKAGE
(TOP VIEW)
REF
1
CATHODE
2
1
3
5
NC − No internal connection
NC − No internal connection
† Pin 2 is attached to Substrate and must be
connected to ANODE or left open.
REF
5
TL431, TL431A, TL431B . . . P (PDIP), PS (SOP),
OR PW (TSSOP) PACKAGE
(TOP VIEW)
NC − No internal connection
CATHODE
6
2
NC − No internal connection
TL431, TL431A, TL431B . . . D (SOIC) PACKAGE
(TOP VIEW)
CATHODE
ANODE
ANODE
NC
1
ANODE
3
2
ANODE
Pin Functions
PIN
TLV431x
NAME
TLV432x
TYPE
DESCRIPTION
DBZ
DBV
PK
D
P, PS
PW
CATHODE
1
3
3
1
1
1
1
1
2
4
1
I/O
REF
2
4
1
8
8
3
3
3
1
5
3
I
Threshold relative to common anode
2
2, 3,
6, 7
6
2
2
6
3
2
2
O
Common pin, normally connected to ground
ANODE
4
3
5
LP
KTP
DCK
DBZ
DBV
PK
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Shunt Current/Voltage input
Copyright © 2004–2018, Texas Instruments Incorporated
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SLVS543P – AUGUST 2004 – REVISED NOVEMBER 2018
7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
VKA
Cathode voltage (2)
IKA
Continuous cathode current range
II(ref)
Reference input current range
TJ
Operating virtual junction temperature
Tstg
Storage temperature range
(1)
(2)
MAX
UNIT
37
V
–100
150
mA
–0.05
10
mA
150
°C
150
°C
–65
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating
Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
All voltage values are with respect to ANODE, unless otherwise noted.
7.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±1000
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 500-V HBM is possible with the necessary precautions.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Manufacturing with
less than 250-V CDM is possible with the necessary precautions.
7.3 Thermal Information
TL43xx
THERMAL METRIC (1)
P
PW
D
PS
8 PINS
DCK
DBV
6 PINS
5 PINS
DBZ
LP
PK
RθJA
Junction-to-ambient thermal
resistance
85
149
97
95
259
206
206
140
52
RθJC(top)
Junction-to-case (top) thermal
resistance
57
65
39
46
87
131
76
55
9
(1)
UNIT
3 PINS
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report (SPRA953).
7.4 Recommended Operating Conditions
See (1)
VKA
Cathode voltage
IKA
Cathode current
MIN
MAX
Vref
36
V
1
100
mA
0
70
TL43xxI
–40
85
TL43xxQ
–40
125
TL43xxC
TA
(1)
Operating free-air temperature
UNIT
°C
Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient
temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability.
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7.5 Electrical Characteristics, TL431C, TL432C
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
Vref
TEST CIRCUIT
Reference voltage
See Figure 20
TEST CONDITIONS
VKA = Vref, IKA = 10 mA
TL431C, TL432C
MIN
TYP
MAX
2440
2495
2550
SOT23-3 and TL432
devices
6
16
All other devices
4
25
–1.4
–2.7
–1
–2
UNIT
mV
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.4
1.2
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
1
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
1
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
VI(dev)
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
6
VKA = Vref,
IKA = 10 mA,
(
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7.6 Electrical Characteristics, TL431I, TL432I
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
Vref
TEST CIRCUIT
Reference voltage
See Figure 20
TL431I, TL432I
TEST CONDITIONS
VKA = Vref, IKA = 10 mA
SOT23-3 and TL432
devices
MIN
TYP
MAX
2440
2495
2550
14
34
5
50
–1.4
–2.7
–1
–2
UNIT
mV
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
1
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
1
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
VI(dev)
|zKA|
(1)
(2)
Dynamic impedance
(2)
VKA = Vref,
IKA = 10 mA
All other devices
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
(
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7.7 Electrical Characteristics, TL431Q, TL432Q
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
TEST CONDITIONS
TL431Q, TL432Q
UNIT
MIN
TYP
MAX
2440
2495
2550
mV
14
34
mV
–1.4
–2.7
–1
–2
Vref
Reference voltage
See Figure 20
VKA = Vref, IKA = 10 mA
VI(dev)
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
VKA = Vref, IKA = 10 mA
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
1
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
1
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 36 V – 10 V
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
8
ΔVKA = 10 V – Vref
(
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7.8 Electrical Characteristics, TL431AC, TL432AC
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
Vref
TEST CIRCUIT
Reference voltage
See Figure 20
TL431AC, TL432AC
TEST CONDITIONS
VKA = Vref, IKA = 10 mA
MIN
TYP
MAX
2470
2495
2520
SOT23-3 and TL432
devices
6
16
All other devices
4
25
–1.4
–2.7
–1
–2
UNIT
mV
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
1.2
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.6
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
VI(dev)
|zKA|
(1)
(2)
Dynamic impedance
(2)
VKA = Vref,
IKA = 10 mA
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
(
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7.9 Electrical Characteristics, TL431AI, TL432AI
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
Vref
TEST CIRCUIT
Reference voltage
See Figure 20
TEST CONDITIONS
VKA = Vref, IKA = 10 mA
SOT23-3 and TL432
devices
TL431AI, TL432AI
MIN
TYP
MAX
2470
2495
2520
14
34
5
50
–1.4
–2.7
–1
–2
UNIT
mV
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.7
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
VI(dev)
|zKA|
(1)
(2)
Dynamic impedance
(2)
All other devices
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
10
VKA = Vref,
IKA = 10 mA
(
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7.10 Electrical Characteristics, TL431AQ, TL432AQ
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
TL431AQ, TL432AQ
TEST CONDITIONS
UNIT
MIN
TYP
MAX
2470
2495
2520
mV
14
34
mV
–1.4
–2.7
–1
–2
Vref
Reference voltage
See Figure 20
VKA = Vref, IKA = 10 mA
VI(dev)
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
VKA = Vref, IKA = 10 mA
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.7
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
(
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7.11 Electrical Characteristics, TL431BC, TL432BC
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
TEST CONDITIONS
TL431BC, TL432BC
UNIT
MIN
TYP
MAX
2483
2495
2507
mV
6
16
mV
–1.4
–2.7
–
–2
Vref
Reference voltage
See Figure 20
VKA = Vref, IKA = 10 mA
VI(dev)
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
VKA = Vref, IKA = 10 mA
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
1.2
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.6
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 36 V – 10 V
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
12
ΔVKA = 10 V – Vref
(
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7.12 Electrical Characteristics, TL431BI, TL432BI
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
TL431BI, TL432BI
TEST CONDITIONS
UNIT
MIN
TYP
MAX
2483
2495
2507
mV
14
34
mV
–1.4
–2.7
–1
–2
Vref
Reference voltage
See Figure 20
VKA = Vref, IKA = 10 mA
VI(dev)
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
VKA = Vref, IKA = 10 mA
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.7
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 10 V – Vref
ΔVKA = 36 V – 10 V
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
(
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7.13 Electrical Characteristics, TL431BQ, TL432BQ
over recommended operating conditions, TA = 25°C (unless otherwise noted)
PARAMETER
TEST CIRCUIT
TEST CONDITIONS
TL431BQ, TL432BQ
UNIT
MIN
TYP
MAX
2483
2495
2507
mV
14
34
mV
–1.4
–2.7
–1
–2
Vref
Reference voltage
See Figure 20
VKA = Vref, IKA = 10 mA
VI(dev)
Deviation of reference input
voltage over full temperature
range (1)
See Figure 20
VKA = Vref, IKA = 10 mA
ΔVref /
ΔVKA
Ratio of change in reference
voltage to the change in
cathode voltage
See Figure 21
IKA = 10 mA
Iref
Reference input current
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
2
4
µA
II(dev)
Deviation of reference input
current over full temperature
range (1)
See Figure 21
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
0.8
2.5
µA
Imin
Minimum cathode current for
regulation
See Figure 20
VKA = Vref
0.4
0.7
mA
Ioff
Off-state cathode current
See Figure 22
VKA = 36 V, Vref = 0
0.1
0.5
µA
See Figure 20
VKA = Vref, f ≤ 1 kHz, IKA = 1 mA to 100 mA
0.2
0.5
Ω
|zKA|
(1)
(2)
Dynamic impedance
(2)
ΔVKA = 36 V – 10 V
mV/V
The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between 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:
αVref is positive or negative, depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
∆VKA
|zKA| =
∆IKA
The dynamic impedance is defined as:
|z'| = ∆V
∆I
When the device is operating with two external resistors (see Figure 21), the total dynamic impedance of the circuit is given by:
|zKA| 1 + R1
R2 .
which is approximately equal to
(
14
ΔVKA = 10 V – Vref
(
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7.14 Typical Characteristics
Data at high and low temperatures are applicable only within the recommended operating free-air temperature
ranges of the various devices.
2600
5
2580
Vref = 2550 mV
2560
4
I ref − Reference Current − µA
V ref − Reference Voltage − mV
R1 = 10 kΩ
R2 =∞
IKA = 10 mA
VKA = Vref
IKA = 10 mA
2540
2520
Vref = 2495 mV
2500
2480
2460
Vref = 2440 mV
2440
3
2
1
2420
2400
−75
−50
−25
0
25
50
75
100
0
−75
125
−50
Figure 1. Reference Voltage vs Free-Air Temperature
25
0
50
75
100
125
Figure 2. Reference Current vs Free-Air Temperature
800
150
VKA = Vref
TA = 25°C
125
VKA = Vref
TA = 25°C
600
I KA − Cathode Current − µ A
100
I KA − Cathode Current − mA
−25
TA − Free-Air Temperature − °C
TA − Free-Air Temperature − °C
75
50
25
0
−25
−50
Imin
400
200
0
−75
−100
−2
−1
0
2
1
−200
−1
3
0
VKA − Cathode Voltage − V
Figure 3. Cathode Current vs Cathode Voltage
3
Figure 4. Cathode Current vs Cathode Voltage
− 0.85
2.5
VKA = 36 V
Vref = 0
VKA = 3 V to 36 V
− 0.95
2
∆V ref / ∆V KA − mV/V
I off − Off-State Cathode Current − µA
2
1
VKA − Cathode Voltage − V
1.5
1
0.5
−1.05
−1.15
−1.25
−1.35
16
0
−75
16
−50
−25
0
25
50
75
100
125
−1.45
−75
−50
−25
0
25
50
75
100
125
TA − Free-Air Temperature − °C
TA − Free-Air Temperature − °C
Figure 5. Off-State Cathode Current
vs Free-Air Temperature
Figure 6. Ratio of Delta Reference Voltage to Delta Cathode
Voltage vs Free-Air Temperature
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Typical Characteristics (continued)
6
IO = 10 mA
TA = 25°C
Vn − Equivalent Input Noise V oltage − nV/
240
V n − Equivalent Input Noise V oltage − µV
Hz
260
220
200
180
160
140
120
16
100
10
100
1k
10 k
5
4
3
2
1
0
−1
−2
−3
f = 0.1 to 10 Hz
IKA = 10 mA
TA = 25°C
−4
−5
−6
100 k
0
1
2
3
f − Frequency − Hz
4
5
7
6
8
9
10
t − Time − s
Figure 7. Equivalent Input Noise Voltage vs Frequency
Figure 8. Equivalent Input Noise Voltage Over a 10-S Period
19.1 V
1 kΩ
500 µF
910 Ω
2000 µF
VCC
TL431
(DUT)
VCC
1 µF
TLE2027
AV = 10 V/mV
+
820 Ω
TLE2027
+
−
16 kΩ
16 kΩ
1 µF
To
Oscilloscope
−
16 Ω
160 kΩ
22 µF
33 kΩ
AV = 2 V/V
0.1 µF
33 kΩ
VEE
VEE
Figure 9. Test Circuit for Equivalent Input Noise Voltage Over a 10-S Period
IKA = 10 mA
TA = 25°C
A V − Small-Signal V oltage Amplification − dB
60
IKA = 10 mA
TA = 25°C
50
Output
40
15 kΩ
IKA
232 Ω
30
9 µF
+
20
8.25 kΩ
10
0
1k
−
GND
10 k
100 k
1M
10 M
f − Frequency − Hz
Figure 10. Small-Signal Voltage Amplification
vs Frequency
16
Figure 11. Test Circuit for Voltage Amplification
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Typical Characteristics (continued)
100
1 kΩ
Output
|z KA| − Reference Impedance − Ω
IKA = 10 mA
TA = 25°C
IKA
50 Ω
10
−
+
GND
1
0.1
1k
10 k
100 k
1M
10 M
f − Frequency − Hz
Figure 12. Reference Impedance vs Frequency
Figure 13. Test Circuit for Reference Impedance
6
220 Ω
TA = 25°C
Output
Input
Input and Output V oltage − V
5
Pulse
Generator
f = 100 kHz
4
3
50 Ω
Output
GND
2
1
0
−1
0
1
2
3
4
5
6
7
t − Time − µs
Figure 14. Pulse Response
100
90
I KA − Cathode Current − mA
80
A V KA
B V KA
C VKA
D VKA
Figure 15. Test Circuit for Pulse Response
150 Ω
= Vref
=5V
= 10 V
= 15 Vf
TA = 25°C
IKA
+
B
VBATT
CL
70
−
Stable
60
C
Stable
50
A
40
TEST CIRCUIT FOR CURVE A
30
D
20
IKA
10
0
0.001
R1 = 10 kΩ
0.01
0.1
1
10
150 Ω
CL
CL − Load Capacitance − µF
+
The areas under the curves represent conditions that may cause
the device to oscillate. For curves B, C, and D, R2 and V+ are
adjusted to establish the initial VKA and IKA conditions, with CL = 0.
VBATT and CL then are adjusted to determine the ranges of
stability.
Figure 16. Stability Boundary Conditions for All TL431 and
TL431A Devices
(Except for SOT23-3, SC-70, and Q-Temp Devices)
R2
VBATT
−
TEST CIRCUIT FOR CURVES B, C, AND D
Figure 17. Test Circuits for Stability Boundary Conditions
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Typical Characteristics (continued)
100
90
I KA − Cathode Current − mA
80
A VKA
B V KA
C VKA
D VKA
150 Ω
= Vref
=5V
= 10 V
= 15 Vf
IKA
+
70
VBATT
CL
B
−
TA = 25°C
60
C
Stable
Stable
50
A
TEST CIRCUIT FOR CURVE A
40
A
30
D
IKA
20
R1 = 10 kΩ
B
150 Ω
10
0
0.001
CL
0.01
0.1
1
+
10
R2
CL − Load Capacitance − µF
The areas under the curves represent conditions that may cause
the device to oscillate. For curves B, C, and D, R2 and V+ are
adjusted to establish the initial VKA and IKA conditions, with CL = 0.
VBATT and CL then are adjusted to determine the ranges of
stability.
Figure 18. Stability Boundary Conditions for All TL431B,
TL432, SOT-23, SC-70, and Q-Temp Devices
18
VBATT
−
TEST CIRCUIT FOR CURVES B, C, AND D
Figure 19. Test Circuit for Stability Boundary Conditions
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8 Parameter Measurement Information
VKA
Input
IKA
Vref
Figure 20. Test Circuit for VKA = Vref
Input
VKA
IKA
R1
Iref
R2
Vref
R1 ö
æ
VKA = Vref ç 1 +
÷ + Iref × R1
R2 ø
è
Figure 21. Test Circuit for VKA > Vref
Input
VKA
Ioff
Figure 22. Test Circuit for Ioff
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9 Detailed Description
9.1 Overview
This standard device has proven ubiquity and versatility across a wide range of applications, ranging from power
to signal path. This is due to it's key components containing an accurate voltage reference & opamp, which are
very fundamental analog building blocks. TL43xx is used in conjunction with it's key components to behave as a
single voltage reference, error amplifier, voltage clamp or comparator with integrated reference.
TL43xx can be operated and adjusted to cathode voltages from 2.5V to 36V, making this part optimum for a wide
range of end equipments in industrial, auto, telecom & computing. In order for this device to behave as a shunt
regulator or error amplifier, >1mA (Imin(max)) must be supplied in to the cathode pin. Under this condition,
feedback can be applied from the Cathode and Ref pins to create a replica of the internal reference voltage.
Various reference voltage options can be purchased with initial tolerances (at 25°C) of 0.5%, 1%, and 2%. These
reference options are denoted by B (0.5%), A (1.0%) and blank (2.0%) after the TL431 or TL432. TL431 & TL432
are both functionaly, but have separate pinout options.
The TL43xxC devices are characterized for operation from 0°C to 70°C, the TL43xxI devices are characterized
for operation from –40°C to 85°C, and the TL43xxQ devices are characterized for operation from –40°C to
125°C.
9.2 Functional Block Diagram
CATHODE
+
REF
_
Vref
ANODE
Figure 23. Equivalent Schematic
CATHODE
800 Ω
800 Ω
20 pF
REF
150 Ω
3.28 kΩ
2.4 kΩ
7.2 kΩ
4 kΩ
10 kΩ
20 pF
1 kΩ
800 Ω
ANODE
Figure 24. Detailed Schematic
20
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9.3 Feature Description
TL43xx consists of an internal reference and amplifier that outputs a sink current base on the difference between
the reference pin and the virtual internal pin. The sink current is produced by the internal Darlington pair, shown
in the above schematic (Figure 24). A Darlington pair is used in order for this device to be able to sink a
maximum current of 100 mA.
When operated with enough voltage headroom (≥ 2.5 V) and cathode current (IKA), TL431 forces the reference
pin to 2.5 V. However, the reference pin can not be left floating, as it needs IREF ≥ 4 µA (please see Electrical
Characteristics, TL431C, TL432C). This is because the reference pin is driven into an npn, which needs base
current in order operate properly.
When feedback is applied from the Cathode and Reference pins, TL43xx behaves as a Zener diode, regulating
to a constant voltage dependent on current being supplied into the cathode. This is due to the internal amplifier
and reference entering the proper operating regions. The same amount of current needed in the above feedback
situation must be applied to this device in open loop, servo or error amplifying implementations in order for it to
be in the proper linear region giving TL43xx enough gain.
Unlike many linear regulators, TL43xx is internally compensated to be stable without an output capacitor
between the cathode and anode. However, if it is desired to use an output capacitor Figure 24 can be used as a
guide to assist in choosing the correct capacitor to maintain stability.
9.4 Device Functional Modes
9.4.1 Open Loop (Comparator)
When the cathode/output voltage or current of TL43xx is not being fed back to the reference/input pin in any
form, this device is operating in open loop. With proper cathode current (Ika) applied to this device, TL43xx will
have the characteristics shown in Figure 23. With such high gain in this configuration, TL43xx is typically used as
a comparator. With the reference integrated makes TL43xx the prefered choice when users are trying to monitor
a certain level of a single signal.
9.4.2 Closed Loop
When the cathode/output voltage or current of TL43xx is being fed back to the reference/input pin in any form,
this device is operating in closed loop. The majority of applications involving TL43xx use it in this manner to
regulate a fixed voltage or current. The feedback enables this device to behave as an error amplifier, computing
a portion of the output voltage and adjusting it to maintain the desired regulation. This is done by relating the
output voltage back to the reference pin in a manner to make it equal to the internal reference voltage, which can
be accomplished via resistive or direct feedback.
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10 Applications and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
As this device has many applications and setups, there are many situations that this datasheet can not
characterize in detail. The linked application notes will help the designer make the best choices when using this
part.
Application note Understanding Stability Boundary Conditions Charts in TL431, TL432 Data Sheet (SLVA482)
will provide a deeper understanding of this devices stability characteristics and aid the user in making the right
choices when choosing a load capacitor. Application note Setting the Shunt Voltage on an Adjustable Shunt
Regulator (SLVA445) assists designers in setting the shunt voltage to achieve optimum accuracy for this device.
10.2 Typical Applications
10.2.1 Comparator With Integrated Reference
Vsup
Rsup
Vout
CATHODE
R1
VIN
RIN
REF
VL
+
R2
2.5V
ANODE
Figure 25. Comparator Application Schematic
22
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Typical Applications (continued)
10.2.1.1 Design Requirements
For this design example, use the parameters listed in Table 1 as the input parameters.
Table 1. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Input Voltage Range
0 V to 5 V
Input Resistance
10 kΩ
Supply Voltage
24 V
Cathode Current (Ik)
5 mA
Output Voltage Level
~2 V – VSUP
Logic Input Thresholds VIH/VIL
VL
10.2.1.2 Detailed Design Procedure
When using TL431 as a comparator with reference, determine the following:
• Input Voltage Range
• Reference Voltage Accuracy
• Output logic input high and low level thresholds
• Current Source resistance
10.2.1.2.1 Basic Operation
In the configuration shown in Figure 25 TL431 will behave as a comparator, comparing the VREF pin voltage to
the internal virtual reference voltage. When provided a proper cathode current (IK), TL43xx will have enough
open loop gain to provide a quick response. This can be seen in Figure 26, where the RSUP=10 kΩ (IKA=500 µA)
situation responds much slower than RSUP=1 kΩ (IKA=5 mA). With the TL43xx's max Operating Current (IMIN)
being 1 mA, operation below that could result in low gain, leading to a slow response.
10.2.1.2.1.1 Overdrive
Slow or inaccurate responses can also occur when the reference pin is not provided enough overdrive voltage.
This is the amount of voltage that is higher than the internal virtual reference. The internal virtual reference
voltage will be within the range of 2.5 V ±(0.5%, 1.0% or 1.5%) depending on which version is being used. The
more overdrive voltage provided, the faster the TL431 will respond.
For applications where TL431 is being used as a comparator, it is best to set the trip point to greater than the
positive expected error (i.e. +1.0% for the A version). For fast response, setting the trip point to >10% of the
internal VREF should suffice.
For minimal voltage drop or difference from Vin to the ref pin, it is recommended to use an input resistor
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