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

STMicroelectronics TL1431ACL3T

Name: TL1431ACL3T
Brand: STMicroelectronics
SKU: TL1431ACL3T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL1431ACL3T

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

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

Datasheet:: TL1431ACL3T.pdf

Description:: IC VREF SHUNT ADJ 0.25% SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:3,696

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Product details

Overview

TL1431ACL3T from STMicroelectronics is an adjustable precision shunt voltage reference IC designed for feedback regulation in isolated DC-DC converters, linear regulators, and overvoltage protection circuits. It delivers 2.500 V nominal reference voltage with ±0.25% initial accuracy, supports 1–100 mA sink current, exhibits 0.22 Ω typical dynamic impedance, and operates across –40 °C to +125 °C for automotive-grade power supply monitoring.

For engineers reviewing the TL1431ACL3T datasheet, TL1431ACL3T pinout, TL1431ACL3T application, or TL1431ACL3T equivalent, key selection criteria include output voltage adjustability (2.5 V to 36 V), low temperature coefficient (±13 ppm/°C), cathode current capability, thermal stability in SOT23-3L packaging, and compliance with AEC-Q100 automotive qualification requirements.

Technical Context

The TL1431ACL3T functions as a 2.5 V bandgap-referenced shunt regulator with internal error amplifier and NPN pass transistor. Its reference input (REF) compares against external resistor-divider feedback, while cathode (K) sinks current to maintain regulated voltage at the anode (A) node. The device achieves stable operation with capacitive loads up to 10 µF and maintains regulation down to 0.5 mA minimum cathode current.

It uses a two-terminal configuration (anode and cathode) with a third control terminal (REF) enabling precise voltage setting via external resistors. The SOT23-3L package provides compact footprint and thermal performance suitable for space-constrained automotive and industrial power supplies requiring high-temperature reliability.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.500 V (typical), ±0.25% initial tolerance - enables accurate voltage setting from 2.5 V to 36 V using two external resistors
Sink Current Range	1–100 mA - supports direct regulation of medium-power feedback loops without external amplification
Dynamic Impedance	0.22 Ω (typical) - ensures minimal output voltage variation under load transients in closed-loop systems
Temp. Coefficient	±13 ppm/°C - guarantees < ±30 mV total drift over –40 °C to +125 °C for automotive-grade stability
Operating Temp.	–40 °C to +125 °C - qualified per AEC-Q100 Grade 0, suitable for under-hood and industrial ambient environments
Min. Cathode Current	0.5 mA - allows stable regulation even in ultra-low-power standby modes of power converters
Input Current (REF)	2.5 µA (typical) - minimizes divider resistor power loss and improves efficiency in high-impedance feedback networks

Pinout & Package

SOT23-3L plastic surface-mount package (3-pin, 1.3 mm × 2.9 mm × 1.1 mm), RoHS-compliant and ECOPACK® certified.

Pin/Terminal	Circuit Role	Design Meaning
Anode (A)	Reference ground node	Connected to system ground or return path; defines voltage reference point for REF input
Cathode (K)	Current-sink output	Sinks adjustable current to regulate voltage at external node; handles up to 100 mA continuous
Ref (R)	Feedback input	High-impedance (2.5 µA typ.) input that compares against internal 2.5 V reference to control K current

Key Features

Feature	Design Value
Adjustable output range	2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference parts
Low dynamic impedance	0.22 Ω typical - maintains tight regulation during fast load steps in SMPS feedback paths
Automotive temperature range	–40 °C to +125 °C - validated for engine control units, ADAS power rails, and battery management systems
High ESD robustness	2000 V HBM - withstands handling and board-level electrostatic discharge in production and field environments
Low reference input current	2.5 µA typical - enables use of high-value feedback resistors (>1 MΩ), reducing quiescent power in always-on circuits

Applications

Isolated Flyback Converter Feedback

Programmable Overvoltage Protection

Use Scenario: Primary-side regulation in 12 V/48 V automotive flyback converters where secondary-side sensing is impractical.

IC Role / Device Role / Timing Role: Shunt reference providing precise voltage threshold to optocoupler input, closing feedback loop across isolation barrier.

Use Value: Enables ±1% output regulation without secondary-side controller; 0.22 Ω impedance minimizes opto-LED current variation with line/load changes.

Use Scenario: Monitoring 24 V industrial bus voltage to trigger shutdown if exceeding 27.5 V.

IC Role / Device Role / Timing Role: Adjustable threshold detector with hysteresis implemented via external comparator and resistor network.

Use Value: 0.25% initial accuracy and ±13 ppm/°C TC ensure trip point remains within ±0.3 V over full temperature range, avoiding nuisance trips.

Linear Regulator Reference

Current Sink for LED Biasing

Use Scenario: Precision 5.0 V output in low-noise analog supply for sensor signal conditioning in vehicle cabin modules.

IC Role / Device Role / Timing Role: Shunt reference establishing stable reference for series-pass transistor base drive in discrete LDO architecture.

Use Value: 2.5 µA REF input current allows high-resistance bias network, reducing thermal drift contribution from resistor self-heating.

Use Scenario: Constant-current driver for status LEDs in infotainment head units operating from 5 V rail.

IC Role / Device Role / Timing Role: Adjustable current sink configured with single resistor between REF and cathode to set LED current.

Use Value: 1–100 mA sink range and 0.5 mA minimum regulation current enable dimming down to 1 mA with stable brightness control.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACDBVR	Same 2.5 V reference, ±0.5% initial accuracy, SOT23-3L package, but rated only to +105 °C	Lacks AEC-Q100 qualification and extended temperature range; unsuitable for under-hood use	Select when cost sensitivity outweighs automotive qualification and extended temp requirement
LM4040CIM3-ADJ	Fixed 2.5 V reference only; no adjustable output; 0.5% accuracy; 75 µA max quiescent current	No external resistor adjustment possible; higher REF current limits high-impedance divider use	Choose only for simple fixed-voltage reference needs where adjustability is unnecessary

Compared with TL431ACDBVR and LM4040CIM3-ADJ, TL1431ACL3T uniquely combines AEC-Q100 qualification, ±0.25% accuracy, –40 °C to +125 °C operation, and full 2.5–36 V adjustability-making it the sole fit for automotive feedback and programmable protection where precision and environmental robustness are co-required.

Availability

TL1431ACL3T is available at Aetrix Electronics and suitable for automotive power management, industrial DC-DC converter feedback, and programmable overvoltage protection requiring stable component supply across extended temperature ranges.

Supply support for TL1431ACL3T 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and R&D infrastructure.

The TL1431 product line was developed specifically for high-reliability voltage reference applications in automotive and industrial power systems, emphasizing precision, thermal stability, and long-term parametric consistency.

FAQ

What is the minimum cathode current required for regulation in TL1431ACL3T?

The TL1431ACL3T requires a minimum cathode current of 0.5 mA to maintain regulation, verified across –40 °C to +125 °C. This value is specified in Table 4 of the datasheet under "Imin Minimum cathode current for regulation" and enables stable operation in low-power standby modes of automotive power supplies.

Can TL1431ACL3T be used with capacitive loads, and what is the maximum stable value?

Yes, TL1431ACL3T supports capacitive loads up to 10 µF while maintaining stability, as confirmed in Figure 20 of the datasheet. The device remains in the stable region for all VKA values (5 V to 24 V) with capacitive loads ≤10 µF, making it suitable for filtering in feedback nodes of switching regulators.

How does the reference input current (Iref) vary with temperature?

Iref remains tightly bounded between 1.5 µA and 3.0 µA over the full –40 °C to +125 °C range, with typical value 2.5 µA at 25 °C. This low and stable input current minimizes power loss in high-impedance feedback dividers and reduces thermal drift contributions from resistor self-heating.

What is the meaning of the 'L3' suffix in TL1431ACL3T?

The 'L3' suffix denotes the SOT23-3L package variant-ST's standardized 3-pin, lead-free, RoHS-compliant surface-mount package with 0.95 mm pitch. It is distinct from SO-8 (D), TO-92 (Z), SOT23-5L (L5), and SOT323-6L (CT) variants, and appears in Table 15 of the ordering information.

TL1431ACL3T 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):: 2.5V

Voltage - Output (Max):: 36 V

Current - Output:: 100 mA

Tolerance:: ±0.25%

Temperature Coefficient:: 90ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 600 µA

Operating Temperature:: -20°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

TL1431ACL3T FAQ

1.How can I place an order for TL1431ACL3T through Aetrix?

Please submit a Request for Quotation (RFQ) for TL1431ACL3T 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 TL1431ACL3T reliable?

The price and inventory of TL1431ACL3T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431ACL3T is usually 5 days.

3.What payment methods are accepted for TL1431ACL3T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431ACL3T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL1431ACL3T?

TL1431ACL3T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL1431ACL3T 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 TL1431ACL3T?

For technical support, including TL1431ACL3T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431ACL3T requirements.

6.How does Aetrix verify that TL1431ACL3T is sourced from the original manufacturer or authorized distributors?

All TL1431ACL3T 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 TL1431ACL3T meets industry standards.

7.What is the process for return or replacement of TL1431ACL3T?

All TL1431ACL3T units undergo pre-shipment inspection (PSI). If there is an issue with TL1431ACL3T, 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 TL1431ACL3T part is unused and in its original packaging.

Return procedure for TL1431ACL3T:

1.Submit a request within 90 days.

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

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