Texas Instruments TL431, TL432 User Manual

ref

Input

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432 Precision Programmable Reference

TL431, TL432

1 Features

• Reference voltage tolerance at 25°C – 0.5% (B grade)

– 1% (A grade) – 2% (Standard grade)

• Adjustable output voltage: V

to 36 V

ref

• 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

3 Description

The TL431LI / TL432LI are pin-to-pin alternatives to TL431 / TL432. TL43xLI offers better stability, lower temperature drift (V reference current (I

) for improved system

ref

accuracy.

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 V

ref

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.

), and lower

I(dev)

(approximately

The TL43xxC devices are characterized for operation

Simplified Schematic

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.

Device Information

PART NUMBER

TL43x

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

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.

(1)

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

TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

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1 Features............................................................................1

2 Applications..................................................................... 1

3 Description.......................................................................1

4 Revision History.............................................................. 2

5 Device Comparison Table...............................................3

6 Pin Configuration and Functions...................................4

7 Specifications.................................................................. 5

7.1 Absolute Maximum Ratings........................................ 5

7.2 ESD Ratings............................................................... 5

7.3 Thermal Information....................................................5

7.4 Recommended Operating Conditions.........................5

7.5 Electrical Characteristics, TL431C, TL432C............... 6

7.6 Electrical Characteristics, TL431I, TL432I.................. 7

7.7 Electrical Characteristics, TL431Q, TL432Q...............8

7.8 Electrical Characteristics, TL431AC, TL432AC.......... 9

7.9 Electrical Characteristics, TL431AI, TL432AI........... 10

7.10 Electrical Characteristics, TL431AQ, TL432AQ...... 11

7.11 Electrical Characteristics, TL431BC, TL432BC...... 12

7.12 Electrical Characteristics, TL431BI, TL432BI......... 13

7.13 Electrical Characteristics, TL431BQ, TL432BQ......14

8 Parameter Measurement Information.......................... 19

9 Detailed Description......................................................20

9.1 Overview................................................................... 20

9.2 Functional Block Diagram......................................... 20

9.3 Feature Description...................................................21

9.4 Device Functional Modes..........................................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 Device Nomenclature..............................................31

13.2 Related Links.......................................................... 31

13.3 Receiving Notification of Documentation Updates..31

13.4 Support Resources................................................. 31

13.5 Trademarks.............................................................31

13.6 Electrostatic Discharge Caution..............................32

13.7 Glossary..................................................................32

14 Mechanical, Packaging, and Orderable

Information.................................................................... 32

4 Revision History

Changes from Revision P (November 2018) to Revision Q (July 2022) Page

• Updated the numbering format for tables, figures, and cross-references throughout the document..................1

• Corrected the device names in the Pin Functions table..................................................................................... 4

Changes from Revision O (January 2015) to Revision P (November 2018) 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 (January 2015) 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. ............................................................................0

Changes from Revision M (July 2012) to Revision N (January 2014) Page

• Updated document formatting............................................................................................................................ 1

• Removed Ordering Information table..................................................................................................................4

• Added Application Note links............................................................................................................................ 22

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5 Device Comparison Table

DEVICE PINOUT INITIAL ACCURACY OPERATING FREE-AIR TEMPERATURE (TA)

TL431 TL432

B: 0.5%

A: 1%

(Blank): 2%

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

C: 0°C to 70°C

I: -40°C to 85°C

Q: -40°C to 125°C

Product Folder Links: TL431 TL432

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CATHODE

ANODE

REF

TL431 . . . KTP (PowerFLEX /TO-252) PACKAGE

(TOP VIEW)

ANODE

TL431A, TL431B . . . DCK (SC-70) PACKAGE

(TOP VIEW)

CATHODE

REF

ANODE NC NC

NC − No internal connection

TL431, TL431A, TL431B . . . LP (TO-92/TO-226) PACKAGE

(TOP VIEW)

CATHODE

ANODE

REF

CATHODE

ANODE ANODE

REF ANODE ANODE NC

TL431, TL431A, TL431B . . . D (SOIC) PACKAGE

(TOP VIEW)

CATHODE

NC NC NC

REF NC ANODE NC

TL431, TL431A, TL431B . . . P (PDIP), PS (SOP),

OR PW (TSSOP) PACKAGE

(TOP VIEW)

NC − No internal connection

TL431, TL431A, TL431B . . . DBV (SOT-23-5) PACKAGE

(TOP VIEW)

†

CATHODE

ANODE

REF

TL431, TL431A, TL431B . . . PK (SOT-89) PACKAGE

(TOP VIEW)

REF

ANODE

CATHODE

†

Pin 2 is attached to Substrate and must be connected to ANODE or left open.

NC − No internal connection

TL432, TL432A, TL432B . . . DBV (SOT-23-5) PACKAGE

(TOP VIEW)

ANODE

REF

CATHODE

NC − No internal connection

TL431, TL431A, TL431B . . . DBZ (SOT-23-3) PACKAGE

(TOP VIEW)

TL432, TL432A, TL432B . . . DBZ (SOT-23-3) PACKAGE

(TOP VIEW)

NC − No internal connection

REF

CATHODE

ANODE

CATHODE

REF

ANODE

TL432, TL432A, TL432B . . . PK (SOT-89) PACKAGE

(TOP VIEW)

REF

ANODE

CATHODE

ANODE

TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

6 Pin Configuration and Functions

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NAME

CATHODE 1 3 3 1 1 1 1 1 2 4 1 I/O Shunt Current/Voltage input

REF 2 4 1 8 8 3 3 3 1 5 3 I Threshold relative to common anode

ANODE 3 5 2

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DBZ DBV PK D

2, 3,

6, 7

Table 6-1. Pin Functions

TL431x TL432x

P, PS

LP KTP DCK DBZ DBV PK

6 2 2 6 3 2 2 O Common pin, normally connected to ground

Product Folder Links: TL431 TL432

TYPE DESCRIPTION

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SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7 Specifications

7.1 Absolute Maximum Ratings

TL431, TL432

over operating free-air temperature range (unless otherwise noted)

I(ref)

stg

Cathode voltage

Continuous cathode current range –100 150 mA

Reference input current range –0.05 10 mA

Operating virtual junction temperature 150 °C

Storage temperature range –65 150 °C

(1) 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.

(2) All voltage values are with respect to ANODE, unless otherwise noted.

(2)

7.2 ESD Ratings

Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001

(ESD)

Electrostatic discharge

Charged-device model (CDM), per JEDEC specification JESD22-

(2)

C101

(1)

MIN MAX UNIT

37 V

VALUE UNIT

(1)

±2000

±1000

(1) 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.

(2) 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

(1)

8 PINS 6 PINS 5 PINS 3 PINS

85 149 97 95 259 206 206 140 52

57 65 39 46 87 131 76 55 9

UNITP PW D PS DCK DBV DBZ LP PK

°C/W

θJA

θJC(top)

THERMAL METRIC

Junction-to-ambient thermal resistance

Junction-to-case (top) thermal resistance

(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report (SPRA953).

7.4 Recommended Operating Conditions

(1)

See

MIN MAX UNIT

Cathode voltage V

ref

36 V

Cathode current 1 100 mA

TL43xxC 0 70

Operating free-air temperature

°CTL43xxI –40 85

TL43xxQ –40 125

(1) Maximum power dissipation is a function of T

temperature is PD = (T

– TA)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability.

J(max)

, θJA, and TA. The maximum allowable power dissipation at any allowable ambient

J(max)

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∆I

∆V

|z | =

∆I

∆V

|z'| =

|z |

(

1 +

(

TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7.5 Electrical Characteristics, TL431C, TL432C

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1

See Figure 8-2 IKA = 10 mA

VKA = V IKA = 10 mA,

, IKA = 10 mA 2440 2495 2550 mV

ref

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.4 1.2 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 1 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

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TL431C, TL432C

MIN TYP MAX

SOT23-3 and TL432 devices

6 16

All other devices 4 25

ΔVKA = 10 V – V

ref

–1.4 –2.7

ΔVKA = 36 V – 10 V –1 –2

0.4 1 mA

0.2 0.5 Ω

UNIT

mV/V

(1) The deviation parameters V

the rated temperature range. The average full-range temperature coefficient of the reference input voltage α

is positive or negative, depending on whether minimum V

Vref

ref(dev)

and I

are defined as the differences between the maximum and minimum values obtained over

ref(dev)

or maximum V

ref

, respectively, occurs at the lower temperature.

ref

is defined as:

Vref

(2) The dynamic impedance is defined as:

When the device is operating with two external resistors (see Figure 8-2), the total dynamic impedance of the circuit is given by:

which is approximately equal to

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7.6 Electrical Characteristics, TL431I, TL432I

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1

See Figure 8-2 IKA = 10 mA

VKA = V IKA = 10 mA

, IKA = 10 mA 2440 2495 2550 mV

ref

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 1 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

TL431I, TL432I

MIN TYP MAX

SOT23-3 and TL432 devices

All other devices 5 50

ΔVKA = 10 V – V

ref

ΔVKA = 36 V – 10 V –1 –2

14 34

–1.4 –2.7

0.4 1 mA

0.2 0.5 Ω

UNIT

mV/V

Product Folder Links: TL431 TL432

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TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7.7 Electrical Characteristics, TL431Q, TL432Q

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

, IKA = 10 mA 2440 2495 2550 mV

ref

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1 VKA = V

ref

See Figure 8-2 IKA = 10 mA

, IKA = 10 mA 14 34 mV

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 1 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

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TL431Q, TL432Q

MIN TYP MAX

ΔVKA = 10 V – V

ref

–1.4 –2.7

ΔVKA = 36 V – 10 V –1 –2

0.4 1 mA

0.2 0.5 Ω

UNIT

mV/V

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7.8 Electrical Characteristics, TL431AC, TL432AC

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1

See Figure 8-2 IKA = 10 mA

VKA = V IKA = 10 mA

, IKA = 10 mA 2470 2495 2520 mV

ref

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 1.2 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

TL431AC, TL432AC

MIN TYP MAX

SOT23-3 and TL432 devices

All other devices 4 25

ΔVKA = 10 V – V

ref

ΔVKA = 36 V – 10 V –1 –2

6 16

–1.4 –2.7

0.4 0.6 mA

0.2 0.5 Ω

UNIT

mV/V

Product Folder Links: TL431 TL432

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TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7.9 Electrical Characteristics, TL431AI, TL432AI

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1

See Figure 8-2 IKA = 10 mA

VKA = V IKA = 10 mA

, IKA = 10 mA 2470 2495 2520 mV

ref

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

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TL431AI, TL432AI

MIN TYP MAX

SOT23-3 and TL432 devices

14 34

All other devices 5 50

ΔVKA = 10 V – V

ref

–1.4 –2.7

ΔVKA = 36 V – 10 V –1 –2

0.4 0.7 mA

0.2 0.5 Ω

UNIT

mV/V

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7.10 Electrical Characteristics, TL431AQ, TL432AQ

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

, IKA = 10 mA 2470 2495 2520 mV

ref

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1 VKA = V

ref

See Figure 8-2 IKA = 10 mA

, IKA = 10 mA 14 34 mV

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

TL431AQ, TL432AQ

MIN TYP MAX

ΔVKA = 10 V – V

ref

ΔVKA = 36 V – 10 V –1 –2

–1.4 –2.7

0.4 0.7 mA

0.2 0.5 Ω

UNIT

mV/V

Product Folder Links: TL431 TL432

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TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7.11 Electrical Characteristics, TL431BC, TL432BC

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

, IKA = 10 mA 2483 2495 2507 mV

ref

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1 VKA = V

ref

See Figure 8-2 IKA = 10 mA

, IKA = 10 mA 6 16 mV

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 1.2 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

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TL431BC, TL432BC

MIN TYP MAX

ΔVKA = 10 V – V

ref

–1.4 –2.7

ΔVKA = 36 V – 10 V – –2

0.4 0.6 mA

0.2 0.5 Ω

UNIT

mV/V

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7.12 Electrical Characteristics, TL431BI, TL432BI

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

, IKA = 10 mA 2483 2495 2507 mV

ref

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1 VKA = V

ref

See Figure 8-2 IKA = 10 mA

, IKA = 10 mA 14 34 mV

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

TL431BI, TL432BI

MIN TYP MAX

ΔVKA = 10 V – V

ref

ΔVKA = 36 V – 10 V –1 –2

–1.4 –2.7

0.4 0.7 mA

0.2 0.5 Ω

UNIT

mV/V

Product Folder Links: TL431 TL432

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TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

7.13 Electrical Characteristics, TL431BQ, TL432BQ

over recommended operating conditions, TA = 25°C (unless otherwise noted)

PARAMETER TEST CIRCUIT TEST CONDITIONS

ref

I(dev)

ΔV

ref

ΔV

ref

I(dev)

min

off

|zKA| Dynamic impedance

Reference voltage See Figure 8-1 VKA = V

, IKA = 10 mA 2483 2495 2507 mV

ref

Deviation of reference input voltage over full temperature

(1)

range

Ratio of change in reference

voltage to the change in

See Figure 8-1 VKA = V

ref

See Figure 8-2 IKA = 10 mA

, IKA = 10 mA 14 34 mV

cathode voltage

Reference input current See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 2 4 µA

Deviation of reference input current over full temperature

(1)

range

Minimum cathode current for regulation

Off-state cathode current See Figure 8-3 VKA = 36 V, V

(2)

See Figure 8-2 IKA = 10 mA, R1 = 10 kΩ, R2 = ∞ 0.8 2.5 µA

See Figure 8-1 VKA = V

See Figure 8-1

ref

= 0 0.1 0.5 µA

ref

VKA = V

, f ≤ 1 kHz,

ref

IKA = 1 mA to 100 mA

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TL431BQ, TL432BQ

MIN TYP MAX

ΔVKA = 10 V – V

ref

–1.4 –2.7

ΔVKA = 36 V – 10 V –1 –2

0.4 0.7 mA

0.2 0.5 Ω

UNIT

mV/V

14 Submit Document Feedback

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2500

2480

2420

2400

−75 −50 −25 0 25 50 75

2540

2580

2600

100 125

2460

2560

2520

2440

− Free-Air Temperature − °C

ref

= 2495 mV

ref

= 2440 mV

VKA= V

ref

IKA= 10 mA

ref

= 2550 mV

− Reference Voltage − mV

ref

−75 −25 0 50

100 125

−50 25 75

− Free-Air Temperature − °C

R1 = 10 kΩ R2 =∞ IKA= 10 mA

− Reference Current −ref

µA

−50

−75

−100

125

−25

−2 −1 0 1

100

150

2 3

− Cathode Voltage − V

VKA= V

ref

TA= 25°C

− Cathode Current − mA

400

200

−200

−1 0 1

600

800

2 3

VKA= V

ref

TA= 25°C

VKA− Cathode Voltage − V

min

− Cathode Current −I

Aµ

1.5

0.5

−75 −25 0 50

− Off-State Cathode Current −

2.5

100 125−50 25 75

off

µA

− Free-Air Temperature − °C

VKA= 36 V V

ref

= 0

−1.15

−1.25

−1.35

−1.45

−1.05

− 0.95

− 0.85

− Free-Air Temperature − °C

−75 −25 0 50 100 125−50 25 75

VKA= 3 V to 36 V

− mV/V

∆V

ref

∆V

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Typical Characteristics

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices.

TL431, TL432

Figure 7-1. Reference Voltage vs Free-Air Temperature

Figure 7-3. Cathode Current vs Cathode Voltage

Figure 7-2. Reference Current vs Free-Air Temperature

Figure 7-4. Cathode Current vs Cathode Voltage

Figure 7-5. Off-State Cathode Current vs Free-Air Temperature

Figure 7-6. Ratio of Delta Reference Voltage to Delta Cathode

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Voltage vs Free-Air Temperature

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180

140

120

100

10 100 1 k

220

240

f − Frequency − Hz

260

10 k 100 k

200

160

− Equivalent Input Noise V oltage − nV/

IO= 10 mA TA= 25°C

−1

−2

−4

−5

−6

−3

0 1 2 3 4 5 6

7 8 9 10

t − Time − s

f = 0.1 to 10 Hz IKA= 10 mA TA= 25°C

− Equivalent Input Noise V oltage − µ V

19.1 V

TLE2027

TLE2027 AV= 10 V/mV

0.1 µF

160 kΩ

820 Ω

(DUT)

TL431

16 Ω

910 Ω

2000 µF

1 kΩ

1 µF

16 kΩ 16 kΩ

1 µF

33 kΩ

AV= 2 V/V

22 µF

500 µF

To Oscilloscope

−

TL431, TL432

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Typical Characteristics

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices.

Figure 7-7. Equivalent Input Noise Voltage vs Frequency

Figure 7-9. Test Circuit for Equivalent Input Noise Voltage Over a 10-S Period

Figure 7-8. Equivalent Input Noise Voltage Over a 10-S Period

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1 k 10 k 100 k 1 M 10 M

f − Frequency − Hz

IKA= 10 mA TA= 25°C

− Small-Signal V oltage Amplification − dBA

9 µF

GND

Output

232 Ω

8.25 kΩ

15 kΩ

−

IKA= 10 mA TA= 25°C

0.1 1 k 10 k 100 k 1 M 10 M

f − Frequency − Hz

100

IKA= 10 mA TA= 25°C

− Reference Impedance −

|z | Ω

1 kΩ

50 Ω

GND

Output

−

−1 0 1 2 3 4

Input and Output V oltage − V

5 6 7

Input

Output

TA= 25°C

t − Time − µs

220 Ω

50 Ω

GND

Output

Pulse

Generator

f = 100 kHz

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Typical Characteristics

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices.

TL431, TL432

Figure 7-10. Small-Signal Voltage Amplification vs Frequency

Figure 7-12. Reference Impedance vs Frequency

Figure 7-11. Test Circuit for Voltage Amplification

Figure 7-13. Test Circuit for Reference Impedance

Figure 7-14. Pulse Response

Figure 7-15. Test Circuit for Pulse Response

Product Folder Links: TL431 TL432

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0.001 0.01 0.1 1

100

TA= 25°C

Stable

A VKA= V

ref

B VKA= 5 V C VKA= 10 V D VKA= 15 V

− Load Capacitance − µF

− Cathode Current − mA

150 Ω

R1 = 10 kΩ

BATT

150 Ω

TEST CIRCUIT FOR CURVE A

TEST CIRCUIT FOR CURVES B, C, AND D

−

0.001 0.01 0.1 1

100

Stable

A VKA= V

ref

B VKA= 5 V C VKA= 10 V D VKA= 15 V

− Load Capacitance − µF

− Cathode Current − mA

TA= 25°C

Stable

150

Ω

R1 = 10 kΩ

BATT

150 Ω

TEST CIRCUIT FOR CURVE A

TEST CIRCUIT FOR CURVES B, C, AND D

−

TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

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Typical Characteristics

Data at high and low temperatures are applicable only within the recommended operating free-air temperature ranges of the various devices.

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. V

ranges of stability.

Figure 7-16. Stability Boundary Conditions for All TL431 and

TL431A Devices (Except for SOT23-3, SC-70, and Q-Temp

and CL then are adjusted to determine the

BATT

Devices)

Figure 7-17. Test Circuits for Stability Boundary Conditions

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. V

ranges of stability.

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Figure 7-18. Stability Boundary Conditions for All TL431B,

TL432, SOT-23, SC-70, and Q-Temp Devices

and CL then are adjusted to determine the

BATT

Figure 7-19. Test Circuit for Stability Boundary Conditions

Product Folder Links: TL431 TL432

ref

Input

ref

Input

ref

KA ref ref

V = V 1 + + I × R1

æ ö ç ÷

è ø

off

Input

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8 Parameter Measurement Information

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

TL431, TL432

Figure 8-1. Test Circuit for VKA = V

Figure 8-2. Test Circuit for VKA > V

Figure 8-3. Test Circuit for I

off

ref

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CATHODE

REF

ANODE

ref

ANODE

REF

CATHODE

2.4 kΩ

7.2 kΩ

3.28 kΩ

20 pF

4 kΩ

1 kΩ

800 Ω

20 pF

150 Ω

10 kΩ

TL431, TL432

SLVS543Q – AUGUST 2004 – REVISED JULY 2022

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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 (I 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

(max)) must be supplied in to the cathode pin. Under this condition,

min

20 Submit Document Feedback

Figure 9-1. Equivalent Schematic

Figure 9-2. Detailed Schematic

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TL431, TL432

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 9-2). 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 I

≥ 4 µA (please see Electrical

REF

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 9-2 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 9-1. 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.

Product Folder Links: TL431 TL432

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2.5V

CATHODE

ANODE

REF

Vout

Vsup

Rsup

TL431, TL432

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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

Figure 10-1. Comparator Application Schematic

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10.2.1.1 Design Requirements

For this design example, use the parameters listed in Table 10-1 as the input parameters.

Table 10-1. 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 – V

Logic Input Thresholds VIH/VIL V

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

TL431, TL432

SUP

In the configuration shown in Figure 10-1 TL431 will behave as a comparator, comparing the V

pin voltage

REF

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 10-2, where the R µA) situation responds much slower than R (I

) being 1 mA, operation below that could result in low gain, leading to a slow response.

MIN

10.2.1.2.1.1 Overdrive

=1 kΩ (IKA=5 mA). With the TL43xx's max Operating Current

SUP

=10 kΩ (IKA=500

SUP

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 V

should suffice.

REF

For minimal voltage drop or difference from Vin to the ref pin, it is recommended to use an input resistor <10kΩ to provide Iref.

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Time (s)

Voltage (V)

-0.001 -0.0006 -0.0002 0.0002 0.0006 0.001

-0.5

0.5

1.5

2.5

3.5

4.5

5.5

D001

Vin Vka(Rsup=10k:) Vka(Rsup=1k:)

TL431, TL432

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10.2.1.2.2 Output Voltage and Logic Input Level

In order for TL431 to properly be used as a comparator, the logic output must be readable by the receiving logic device. This is accomplished by knowing the input high and low level threshold voltage levels, typically denoted by VIH & VIL.

As seen in Figure 10-2, TL431's output low level voltage in open-loop/comparator mode is ~2 V, which is typically sufficient for 5V supplied logic. However, would not work for 3.3 V & 1.8 V supplied logic. In order to accomodate this a resistive divider can be tied to the output to attenuate the output voltage to a voltage legible to the receiving low voltage logic device.

TL431's output high voltage is equal to V

due to TL431 being open-collector. If V

SUP

is much higher than the

SUP

receiving logic's maximum input voltage tolerance, the output must be attenuated to accomadate the outgoing logic's reliability.

When using a resistive divider on the output, be sure to make the sum of the resistive divider (R1 & R2 in Figure

10-1) is much greater than R

in order to not interfere with TL431's ability to pull close to V

SUP

when turning

SUP

off.

10.2.1.2.2.1 Input Resistance

TL431 requires an input resistance in this application in order to source the reference current (I

) needed from

REF

this device to be in the proper operating regions while turing on. The actual voltage seen at the ref pin will be V

REF=VIN-IREF*RIN

will mitigate the error that I

. Since I

can be as high as 4 µA it is recommended to use a resistance small enough that

REF

creates from VIN.

REF

10.2.1.3 Application Curve

Figure 10-2. Output Response With Various Cathode Currents

24 Submit Document Feedback

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REF

CATHODE

ANODE

SUP

(

ref

0.1%

TL431

= 1 + V

ref

)

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10.2.2 Shunt Regulator/Reference

Figure 10-3. Shunt Regulator Schematic

10.2.2.1 Design Requirements

For this design example, use the parameters listed in Table 10-1 as the input parameters.

Table 10-2. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE

Reference Initial Accuracy 1.0 %

Supply Voltage 24 V

Cathode Current (Ik) 5 mA

Output Voltage Level 2.5 V - 36 V

Load Capacitance 100 nF

Feedback Resistor Values and Accuracy (R1 & R2) 10 kΩ

TL431, TL432

10.2.2.2 Detailed Design Procedure

When using TL431 as a Shunt Regulator, determine the following:

• Input Voltage Range

• Temperature Range

• Total Accuracy

• Cathode Current

• Reference Initial Accuracy

• Output Capacitance

10.2.2.2.1 Programming Output/Cathode Voltage

In order to program the cathode voltage to a regulated voltage a resistive bridge must be shunted between the cathode and anode pins with the mid point tied to the reference pin. This can be seen in Figure 10-3, with R1 & R2 being the resistive bridge. The cathode/output voltage in the shunt regulator configuration can be approximated by the equation shown in Figure 10-3. The cathode voltage can be more accuratel determined by taking in to account the cathode current:

Vo=(1+R1/R2)*V

REF-IREF

*R1

In order for this equation to be valid, TL43xx must be fully biased so that it has enough open loop gain to mitigate any gain error. This can be done by meeting the Imin spec denoted in Electrical Characteristics,

TL431C, TL432C.

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+ 58 hidden pages

Texas Instruments TL431, TL432 User Manual

1 Features

2 Applications

3 Description

Table of Contents

4 Revision History

5 Device Comparison Table

6 Pin Configuration and Functions

7 Specifications

7.1 Absolute Maximum Ratings

7.2 ESD Ratings

7.3 Thermal Information

7.4 Recommended Operating Conditions

7.5 Electrical Characteristics, TL431C, TL432C

7.6 Electrical Characteristics, TL431I, TL432I

7.7 Electrical Characteristics, TL431Q, TL432Q

7.8 Electrical Characteristics, TL431AC, TL432AC

7.9 Electrical Characteristics, TL431AI, TL432AI

7.10 Electrical Characteristics, TL431AQ, TL432AQ

7.11 Electrical Characteristics, TL431BC, TL432BC

7.12 Electrical Characteristics, TL431BI, TL432BI

7.13 Electrical Characteristics, TL431BQ, TL432BQ

8 Parameter Measurement Information

9 Detailed Description

9.1 Overview

9.2 Functional Block Diagram

9.3 Feature Description

9.4 Device Functional Modes

9.4.1 Open Loop (Comparator)

9.4.2 Closed Loop

10 Applications and Implementation

10.1 Application Information

10.2 Typical Applications

10.2.1 Comparator With Integrated Reference

10.2.1.1 Design Requirements

10.2.1.2 Detailed Design Procedure

10.2.1.2.1 Basic Operation

10.2.1.2.1.1 Overdrive

10.2.1.2.2 Output Voltage and Logic Input Level

10.2.1.2.2.1 Input Resistance

10.2.1.3 Application Curve

10.2.2 Shunt Regulator/Reference

10.2.2.1 Design Requirements

10.2.2.2 Detailed Design Procedure

10.2.2.2.1 Programming Output/Cathode Voltage