Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Reference

STMicroelectronics TL431AIL3T

Name: TL431AIL3T
Brand: STMicroelectronics
SKU: TL431AIL3T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: TL431AIL3T

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: TL431AIL3T.pdf

Description:: IC VREF SHUNT ADJ 1% SOT23-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,518

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

TL431AIL3T from STMicroelectronics is an AEC-Q100 qualified automotive-grade adjustable shunt voltage reference with 1% initial voltage precision (2.5 V nominal), operating over –40 °C to +125 °C, supporting 1–100 mA sink current and delivering 0.22 Ω typical dynamic impedance - used in feedback loops of isolated DC-DC converters and battery management systems.

For engineers reviewing the TL431AIL3T datasheet, TL431AIL3T pinout, TL431AIL3T application, or TL431AIL3T equivalent, key selection criteria include automotive temperature compliance, shunt reference stability under variable load, cathode-anode voltage range (2.5–36 V), and SOT23-3 package suitability for space-constrained power supply designs.

Technical Context

The TL431AIL3T implements a precision bandgap-based reference amplifier driving an NPN output transistor in shunt configuration. Its internal 2.5 V reference is trimmed at wafer level to ±1% accuracy across the full –40 °C to +125 °C automotive range, with guaranteed thermal drift performance.

It operates as a two-terminal programmable shunt regulator: the REF pin senses external resistor divider voltage, while cathode and anode form the current-sinking path. Dynamic impedance remains ≤0.5 Ω up to 100 mA, enabling stable regulation even with fast load transients in automotive power supplies.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.5 V ±1% (2.47–2.53 V) at 10 mA cathode current, ensuring accurate feedback setpoint in closed-loop regulators.
Operating Temperature	–40 °C to +125 °C (automotive grade), validated per AEC-Q100, enabling use in engine control units and ADAS power rails.
Sink Current Range	1–100 mA continuous, allowing direct interface with optocoupler LEDs or error amplifiers without external buffering.
Dynamic Impedance	0.22 Ω typical (≤0.5 Ω max), minimizing output voltage deviation during rapid load changes in SMPS feedback paths.
Cathode-Anode Voltage	2.5–36 V, supporting wide-input industrial and automotive DC-DC topologies including flyback and forward converters.
Reference Input Current	≤4 µA typical (≤6.5 µA max), reducing divider network power loss and improving high-impedance sensing accuracy.
Thermal Resistance	R_thJA = 157 °C/W (SOT23-3), defining maximum power dissipation (≈350 mW at T_A = 85 °C) for thermal design margining.

Pinout & Package

SOT23-3 plastic surface-mount package (3-pin, 1.3 mm × 2.9 mm footprint), optimized for automated assembly and thermal performance in compact power modules.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Anode)	Anode terminal	Low-side return path for shunt current; connects to system ground or negative rail in standard configurations.
Pin 2 (Cathode)	Cathode terminal	Main current-sinking output; ties to feedback node of isolated DC-DC converter or voltage monitor point.
Pin 3 (Ref)	Reference input	High-impedance sense input; connected to resistor divider midpoint to set regulated output voltage (V_OUT = 2.5 × (1 + R1/R2)).

Key Features

Feature	Design Value
AEC-Q100 qualification	Validated for automotive applications including powertrain and body electronics, with extended temperature stress testing.
Adjustable output voltage	Programmable from 2.5 V to 36 V using only two external resistors - eliminates need for multiple fixed-reference ICs.
Low dynamic impedance	0.22 Ω typical ensures minimal output voltage perturbation during transient load steps in switching regulators.
Wide cathode current range	Operates stably from 1 mA minimum to 100 mA maximum, supporting both low-power monitoring and high-current regulation.
Low reference input current	≤4 µA typical reduces power loss in high-value resistor dividers, enabling precise voltage setting with minimal bias error.

Applications

Automotive DC-DC Converter

Industrial Isolated Power Supply

Use Scenario: Feedback regulation in 12 V/48 V bidirectional DC-DC converters for 48 V mild-hybrid vehicles.

IC Role / Device Role / Timing Role: Shunt reference in optocoupler-coupled secondary-side feedback loop, setting precise output voltage despite primary-side isolation.

Use Value: Maintains ±1% output accuracy over –40 °C to +125 °C ambient, meeting ASIL-B functional safety requirements for power conversion stability.

Use Scenario: Secondary-side voltage regulation in industrial PLC power supplies with reinforced isolation barriers.

IC Role / Device Role / Timing Role: Programmable shunt reference interfacing with linear optocoupler to close feedback loop across isolation boundary.

Use Value: Enables <1% output tolerance without trimming, reducing BOM count and calibration labor in high-volume industrial power modules.

Battery Management System (BMS)

LED Driver Current Regulation

Use Scenario: Precision voltage reference for cell voltage monitoring and charge termination thresholds in EV traction battery packs.

IC Role / Device Role / Timing Role: Stable 2.5 V reference source for ADC reference inputs and comparator trip points in analog front-end circuits.

Use Value: Delivers <±30 mV total voltage deviation over full temperature range, directly improving state-of-charge estimation accuracy.

Use Scenario: Constant-current regulation for high-brightness LED strings in automotive lighting modules.

IC Role / Device Role / Timing Role: Shunt reference controlling MOSFET gate drive via op-amp feedback to maintain fixed LED current.

Use Value: Ensures luminous flux stability within ±2% over vehicle lifetime, meeting ECE R149 photometric consistency requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable shunt reference applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACL3T	Same SOT23-3 package and 1% accuracy, but rated for –40 °C to +105 °C (industrial grade, not AEC-Q100).	Lacks automotive qualification; unsuitable for under-hood or powertrain applications requiring AEC-Q100 compliance.	Select when cost-sensitive industrial designs do not require automotive reliability validation.
TL431BIL3T	0.5% initial accuracy (tighter tolerance), same automotive temperature range and SOT23-3 package.	Higher precision enables tighter output regulation in premium ADAS power supplies where <±10 mV error is critical.	Choose when system-level voltage accuracy demands exceed ±1%, such as in radar module LDO references.

Compared with TL431ACL3T, TL431AIL3T adds AEC-Q100 qualification for automotive deployment; compared with TL431BIL3T, it trades 0.5% precision for lower unit cost while retaining full automotive thermal and reliability specs.

Availability

TL431AIL3T is available at Aetrix Electronics and suitable for automotive power conversion, industrial isolated supplies, and battery management systems requiring stable component supply with long-term lifecycle support.

Supply support for TL431AIL3T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, and analog components for automotive, industrial, and consumer markets.

The TL431 series belongs to ST's precision analog portfolio, engineered specifically for high-reliability voltage reference applications in harsh environments - emphasizing thermal stability, long-term drift control, and automotive qualification readiness.

FAQ

What is the maximum cathode-to-anode voltage for TL431AIL3T?

The absolute maximum cathode-to-anode voltage is 37 V, with recommended operating range from 2.5 V to 36 V. Exceeding 37 V risks permanent device damage due to junction breakdown, and operation above 36 V may degrade long-term stability and thermal performance in automotive environments.

Can TL431AIL3T be used in three-terminal regulator configurations?

No - TL431AIL3T is a two-terminal shunt regulator (anode and cathode carry current; REF is a high-impedance sense input). It cannot replace a three-terminal series regulator like LM78xx. It must be used with an external pass element (e.g., transistor or MOSFET) when series regulation topology is required.

How does the SOT23-3 package affect thermal performance in continuous operation?

With R_thJA = 157 °C/W, TL431AIL3T dissipates up to ~350 mW at 85 °C ambient before reaching its 150 °C junction limit. For >200 mW continuous dissipation, PCB copper pour under the exposed pad (if present) or thermal vias are strongly recommended to reduce effective R_thJA.

Is the 1% voltage accuracy maintained across the full –40 °C to +125 °C range?

Yes - the 1% specification (2.47–2.53 V) applies over the entire automotive operating temperature range. Total deviation over temperature is limited to ±30 mV (±1.2% of 2.5 V), confirmed by characterization data in Table 5 of the datasheet for TL431AI/TL432AI variants.

TL431AIL3T Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: TO-236-3, SC-59, SOT-23-3

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Active

Reference Type:: Shunt

Output Type:: Adjustable

Voltage - Output (Min/Fixed):: 2.495V

Voltage - Output (Max):: 36 V

Current - Output:: 100 mA

Tolerance:: ±1%

Temperature Coefficient:: -

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 700 µA

Operating Temperature:: -40°C ~ 105°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

TL431AIL3T FAQ

1.How can I place an order for TL431AIL3T through Aetrix?

Please submit a Request for Quotation (RFQ) for TL431AIL3T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TL431AIL3T reliable?

The price and inventory of TL431AIL3T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431AIL3T is usually 5 days.

3.What payment methods are accepted for TL431AIL3T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431AIL3T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL431AIL3T?

TL431AIL3T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL431AIL3T order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TL431AIL3T?

For technical support, including TL431AIL3T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431AIL3T requirements.

6.How does Aetrix verify that TL431AIL3T is sourced from the original manufacturer or authorized distributors?

All TL431AIL3T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TL431AIL3T meets industry standards.

7.What is the process for return or replacement of TL431AIL3T?

All TL431AIL3T units undergo pre-shipment inspection (PSI). If there is an issue with TL431AIL3T, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TL431AIL3T part is unused and in its original packaging.

Return procedure for TL431AIL3T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…