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

STMicroelectronics TL1431CL3T

Name: TL1431CL3T
Brand: STMicroelectronics
SKU: TL1431CL3T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL1431CL3T

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

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

Datasheet:: TL1431CL3T.pdf

Description:: IC VREF SHUNT ADJ 0.4% SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,520

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Product details

Overview

TL1431CL3T from STMicroelectronics is an adjustable shunt voltage reference IC with 0.4% initial voltage precision, 2.5 V to 36 V programmable output via two external resistors, and guaranteed operation from −40 °C to +70 °C. It delivers 1–100 mA sink current with 0.22 Ω typical dynamic impedance and supports automotive-grade thermal stability in SOT23-3L packaging.

For engineers reviewing the TL1431CL3T datasheet, TL1431CL3T pinout, TL1431CL3T application, or TL1431CL3T equivalent, this device serves as a precision voltage setpoint in feedback loops for DC-DC converters, linear regulators, and overvoltage protection circuits where compact size and temperature-stable reference accuracy are critical.

Technical Context

The TL1431CL3T implements a bandgap-based reference core with internal error amplifier and NPN pass transistor, configured as a 3-terminal shunt regulator. Its cathode-anode voltage regulation range spans 2.5 V to 36 V, controlled by external resistor divider on the REF pin.

It operates across 1–100 mA cathode current with <0.5 Ω max dynamic impedance at 1 kHz, and maintains ≤30 mV total reference voltage deviation over its −40 °C to +70 °C operating range. The SOT23-3L package enables surface-mount integration in space-constrained power management subsystems.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.500 V (typical), ±0.4% initial tolerance - sets precise feedback threshold in closed-loop regulation.
Output Voltage Range	2.5 V to 36 V - programmable via external R1/R2 divider without requiring additional op-amps.
Sink Current Range	1 mA to 100 mA - supports direct drive of optocoupler LEDs or error amplifier inputs in isolated SMPS.
Dynamic Impedance	0.22 Ω (typical) - ensures minimal output voltage perturbation under fast load transients.
Temp. Stability	±30 mV over −40 °C to +70 °C - guarantees consistent regulation across industrial ambient conditions.
Package	SOT23-3L - 2.9 mm × 2.4 mm footprint with 0.95 mm pitch, suitable for high-density PCB layouts.
ESD Rating	2000 V HBM - provides robustness against handling-induced electrostatic discharge during assembly.

Pinout & Package

SOT23-3L plastic surface-mount package with gull-wing leads, 1.45 mm height, and moisture sensitivity level (MSL) 1 per JEDEC J-STD-020.

Pin	Circuit Role	Design Meaning
Anode (Pin 1)	Reference ground node	Connected to system ground or return path; establishes common reference for internal bandgap and error amp.
Cathode (Pin 2)	Current-sink output terminal	Delivers regulated current to external load; voltage at this pin equals programmed V_OUT when used in shunt configuration.
Ref (Pin 3)	Adjust input / feedback sense	Internal 2.5 V reference node; connected to resistor divider midpoint to set output voltage per V_OUT = 2.5 × (1 + R1/R2).

Key Features

Feature	Design Value
Adjustable output voltage	2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-voltage references in BOM.
Low dynamic impedance	0.22 Ω typical - improves transient response and reduces output ripple in feedback-controlled supplies.
Wide cathode current range	1–100 mA - accommodates both low-power sensing and higher-current shunt regulation without external buffering.
Automotive-grade temp. range	−40 °C to +70 °C - qualified for under-hood and industrial control applications with extended thermal margins.
Compact SOT23-3L package	2.9 mm × 2.4 mm footprint - enables miniaturized designs in space-constrained power modules and embedded systems.

Applications

AC-DC Adapter Feedback

Isolated DC-DC Converter

Use Scenario: Secondary-side voltage sensing in flyback converters with optocoupler isolation.

IC Role / Device Role / Timing Role: Shunt reference providing stable 2.5 V reference to optocoupler LED driver, enabling precise primary-side regulation.

Use Value: Maintains ±1% output voltage accuracy across line/load/temperature with no secondary-side LDO required.

Use Scenario: Output voltage monitoring in isolated 12 V → 3.3 V DC-DC modules for telecom equipment.

IC Role / Device Role / Timing Role: Adjustable shunt reference setting 3.3 V output via R1/R2 divider, interfacing directly with error amplifier input.

Use Value: Eliminates need for dedicated voltage monitor IC; reduces component count while preserving tight regulation.

Overvoltage Protection Circuit

Programmable Current Limiter

Use Scenario: Clamp circuit protecting downstream 5 V logic rails from >5.5 V surges in industrial I/O modules.

IC Role / Device Role / Timing Role: Precision shunt element triggering MOSFET gate shutdown when sensed voltage exceeds 5.5 V threshold.

Use Value: Achieves ±25 mV trip point accuracy over −40 °C to +70 °C, reducing false trips vs. Zener-based solutions.

Use Scenario: Constant-current source for LED biasing in automotive interior lighting drivers.

IC Role / Device Role / Timing Role: Reference node for op-amp-controlled current mirror, with V_REF = 2.5 V setting 100 mA output.

Use Value: Delivers <1% current variation across temperature due to low TC and stable dynamic impedance.

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	0.25% initial voltage tolerance (vs. 0.4%); identical SOT23-3L pinout and electrical specs.	Preferred where tighter regulation is required in high-accuracy feedback paths (e.g., medical power supplies).	Select TL431ACL3T if ±0.25% reference precision is mandatory; otherwise TL1431CL3T offers cost-effective performance.
LM431AIM3X/NOPB	0.5% tolerance, −25 °C to +85 °C operating range, same SOT23-3 package but different pin assignment (Anode/Cathode/Ref order differs).	Not drop-in compatible due to reversed Anode/Cathode pinout; requires PCB layout revision.	Choose LM431AIM3X only if legacy design compatibility or TI supply chain preference dictates; verify pin mapping before substitution.

Compared with TL431ACL3T, TL1431CL3T trades 0.15% precision for lower unit cost while retaining identical thermal stability and dynamic response; versus LM431AIM3X, it offers wider temperature range and guaranteed pinout compatibility but requires sourcing from ST's distribution network.

Availability

TL1431CL3T is available at Aetrix Electronics and suitable for AC-DC adapters, isolated DC-DC converters, and overvoltage protection circuits requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for TL1431CL3T 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 industrial, automotive, and consumer markets.

The TL1431 belongs to ST's precision analog reference product line, engineered specifically for high-stability voltage setpoints in power supply feedback networks and protection circuitry where reliability across temperature extremes is essential.

FAQ

What is the minimum cathode current required for regulation in TL1431CL3T?

The TL1431CL3T requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of the datasheet under "Imin Minimum cathode current for regulation." Below this threshold, the device exits regulation and output voltage becomes uncontrolled. This value is verified across −40 °C to +70 °C ambient temperature.

Can TL1431CL3T be used in place of TL431ACL3T without circuit modification?

Yes - TL1431CL3T and TL431ACL3T share identical SOT23-3L pinout (Anode/Cathode/Ref), electrical architecture, and absolute maximum ratings. The only difference is initial voltage tolerance (0.4% vs. 0.25%). No schematic or layout changes are needed for substitution, though system-level accuracy verification is recommended.

What is the thermal resistance junction-to-ambient (RthJA) for TL1431CL3T in SOT23-3L package?

The SOT23-3L variant of TL1431CL3T has a junction-to-ambient thermal resistance of 248 °C/W, as documented in Table 3 ("Thermal data") of the datasheet. This value assumes standard JEDEC 2-layer board layout; actual thermal performance improves with copper pour and thermal vias.

Does TL1431CL3T support capacitive loads, and what is the stability limit?

Yes - TL1431CL3T remains stable with capacitive loads up to 10 µF, as shown in Figure 20 ("Stability behavior with capacitive loads"). For loads >1 µF, a series resistor (typically 1–10 Ω) between cathode and capacitor is recommended to ensure phase margin >45° across operating conditions.

TL1431CL3T 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:: ±0.4%

Temperature Coefficient:: 90ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 1 mA

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

TL1431CL3T FAQ

1.How can I place an order for TL1431CL3T through Aetrix?

Please submit a Request for Quotation (RFQ) for TL1431CL3T 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 TL1431CL3T reliable?

The price and inventory of TL1431CL3T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431CL3T is usually 5 days.

3.What payment methods are accepted for TL1431CL3T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431CL3T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL1431CL3T?

TL1431CL3T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL1431CL3T 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 TL1431CL3T?

For technical support, including TL1431CL3T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431CL3T requirements.

6.How does Aetrix verify that TL1431CL3T is sourced from the original manufacturer or authorized distributors?

All TL1431CL3T 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 TL1431CL3T meets industry standards.

7.What is the process for return or replacement of TL1431CL3T?

All TL1431CL3T units undergo pre-shipment inspection (PSI). If there is an issue with TL1431CL3T, 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 TL1431CL3T part is unused and in its original packaging.

Return procedure for TL1431CL3T:

1.Submit a request within 90 days.

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

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