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

STMicroelectronics TL431CL5T

Name: TL431CL5T
Brand: STMicroelectronics
SKU: TL431CL5T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL431CL5T

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: SC-74A, SOT-753

Datasheet:: TL431CL5T.pdf

Description:: IC VREF SHUNT ADJ 2.21% SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:8,967

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Product details

Overview

TL431CL5T from STMicroelectronics is an AEC-Q100 qualified automotive-grade adjustable shunt voltage reference in SOT23-5 package, delivering 2.5–36 V programmable output with ±2% initial accuracy, 1–100 mA sink current capability, and 0.22 Ω typical dynamic impedance for precision feedback in isolated DC-DC converters and battery management systems.

For engineers reviewing the TL431CL5T datasheet, TL431CL5T pinout, TL431CL5T application, or TL431CL5T equivalent, key selection criteria include automotive temperature range (−40 °C to +125 °C), cathode-to-anode voltage rating (37 V), minimum regulation current (0.6 mA), reference input current (≤4 µA), and thermal resistance (67 °C/W junction-to-case).

Technical Context

The TL431CL5T implements a precision 2.5 V internal bandgap reference with high-gain error amplifier driving an NPN output stage, enabling stable shunt regulation across wide load and line variations. Its architecture supports both fixed and adjustable configurations via external resistor dividers.

It operates as a three-terminal programmable shunt regulator where the REF pin senses voltage, the CATHODE sinks current to ground, and the ANODE connects to the regulated rail. The device maintains regulation over −40 °C to +125 °C with guaranteed 0.5% voltage deviation over temperature for the B-grade variant - though TL431CL5T is the 2% accuracy version.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage Range	2.5 V to 36 V - set externally via two resistors; enables flexible feedback design for diverse power topologies.
Initial Accuracy	±2% at 25 °C - defines maximum output error before temperature and load effects; suitable for cost-sensitive automotive subsystems.
Sink Current Range	1 mA to 100 mA - determines compatible optocoupler LED drive strength and loop compensation stability margin.
Dynamic Impedance	0.22 Ω typical - ensures minimal output voltage perturbation under fast load transients; critical for tight regulation.
Operating Temperature	−40 °C to +125 °C - validated for under-hood automotive applications including engine control units and ADAS power supplies.
Cathode-Anode Voltage Max	37 V - sets absolute upper limit for input rail voltage; constrains use in >36 V systems without series protection.
Reference Input Current	≤4 µA max - reduces divider network power loss and improves high-impedance feedback accuracy.

Pinout & Package

SOT23-5 plastic surface-mount package with 5 terminals: Cathode (pin 1), Anode (pin 2), Reference (pin 3), NC (pin 4), NC (pin 5). Thermal resistance is 67 °C/W (junction-to-case) and 157 °C/W (junction-to-ambient), supporting moderate power dissipation in compact layouts.

Pin/Terminal	Circuit Role	Design Meaning
1 - Cathode	Current sink output	Connects to regulated rail; sinks current to maintain reference voltage at REF pin.
2 - Anode	Return path	Typically tied to system ground; completes current path for shunt operation.
3 - Ref	Voltage sense input	High-impedance node comparing external divider voltage to internal 2.5 V reference.
4 - NC	No connection	Internally unconnected; must remain floating or grounded per layout best practices.
5 - NC	No connection	Internally unconnected; no electrical function; avoid routing signals nearby.

Key Features

Feature	Design Value
AEC-Q100 qualification	Validated for automotive applications including engine control, body electronics, and infotainment power rails.
Adjustable output (2.5–36 V)	Enables single BOM part to support multiple output voltages across product families without redesign.
Low dynamic impedance (0.22 Ω)	Minimizes output voltage ripple during transient load steps; improves PSRR in feedback loops.
Wide sink current (1–100 mA)	Directly drives standard optocouplers (e.g., PC817, SFH615A) without external buffer transistors.
Stable over −40 °C to +125 °C	Eliminates need for external temperature compensation in harsh-environment designs.

Applications

Automotive Power Supply

Industrial SMPS Feedback

Use Scenario: Primary-side feedback in isolated flyback converters powering automotive ECUs.

IC Role / Device Role / Timing Role: Shunt regulator providing precise voltage reference to optocoupler LED, closing secondary-side regulation loop.

Use Value: Enables ±2% output regulation across temperature and line variations while meeting AEC-Q100 reliability requirements.

Use Scenario: Output voltage sensing in industrial AC/DC adapters and DIN-rail power supplies.

IC Role / Device Role / Timing Role: Adjustable reference element in TL431-based feedback network controlling PWM duty cycle.

Use Value: Delivers stable 0.22 Ω dynamic impedance to suppress noise-induced regulation errors in noisy factory environments.

Battery Management System

Programmable Current Sink

Use Scenario: Cell voltage monitoring and balancing circuitry in 12 V–48 V automotive battery packs.

IC Role / Device Role / Timing Role: Precision shunt reference setting threshold for comparator-based cell overvoltage detection.

Use Value: Maintains ±2% accuracy over −40 °C to +125 °C, ensuring safe cutoff thresholds despite under-hood thermal cycling.

Use Scenario: Constant-current load for LED driver testing and analog calibration fixtures.

IC Role / Device Role / Timing Role: Programmable shunt sink regulating current through external sense resistor.

Use Value: Achieves 1–100 mA sink range with <4 µA reference bias, minimizing measurement uncertainty in test equipment.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACL5T	±1% initial accuracy vs. ±2% for TL431CL5T; otherwise identical pinout, package, and temperature range.	Required where tighter output tolerance is needed for high-precision feedback (e.g., medical-grade power supplies).	Select TL431ACL5T when system-level voltage regulation budget demands <1% error contribution from reference.
TL431IL5T	Same ±2% accuracy but rated for −40 °C to +105 °C (vs. +125 °C); otherwise identical SOT23-5 footprint and electrical specs.	Suitable for non-under-hood automotive modules (e.g., infotainment, HVAC) where ambient temperature stays below 105 °C.	Choose TL431IL5T to reduce cost where full AEC-Q100 automotive grade is not required.

Compared with TL431CL5T, TL431ACL5T trades higher accuracy for slightly increased cost, while TL431IL5T offers cost savings by relaxing the upper temperature limit - both retain identical pin compatibility and dynamic performance for drop-in evaluation.

Availability

TL431CL5T is available at Aetrix Electronics and suitable for automotive power supplies, industrial SMPS feedback networks, and battery management systems requiring stable component supply with AEC-Q100 compliance and extended temperature operation.

Supply support for TL431CL5T 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 ICs, sensors, and analog components for automotive, industrial, and consumer markets.

The TL431 product line delivers precision programmable shunt references optimized for feedback control in isolated power converters, with variants engineered specifically for automotive reliability, industrial robustness, and cost-sensitive consumer applications.

FAQ

What is the maximum cathode-to-anode voltage for TL431CL5T?

The absolute maximum cathode-to-anode voltage (V_KA) is 37 V. Exceeding this risks permanent damage. In normal operation, the device regulates when V_KA ≥ V_REF (2.5 V) and ≤ 36 V, with derating recommended above 30 V for long-term reliability under thermal stress.

Can TL431CL5T replace TL431CD in SO-8 packages?

No - TL431CL5T uses SOT23-5 packaging with different pinout, thermal characteristics, and footprint. While electrically similar, it is not a drop-in replacement for SO-8 versions due to mechanical incompatibility and lower power dissipation (67 °C/W vs. 85 °C/W for SO-8). PCB redesign is required.

Does TL431CL5T require external capacitors for stability?

Yes - stability depends on output capacitance and loop gain. The datasheet recommends ≥10 nF ceramic capacitor from cathode to anode for phase margin >45° with typical optocoupler loads. Larger values (>100 nF) may be needed for high-ESR electrolytic outputs or low-frequency compensation.

How does the 2% accuracy affect output voltage programming?

With external resistor divider R1/R2, output voltage is V_OUT = 2.5 × (1 + R1/R2). A ±2% V_REF error directly contributes ±2% to V_OUT, independent of resistor tolerance. For example, a 12 V target may vary between 11.76 V and 12.24 V at 25 °C before adding resistor and temperature drift contributions.

TL431CL5T Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: SC-74A, SOT-753

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:: ±2.21%

Temperature Coefficient:: -

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 1 mA

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

TL431CL5T FAQ

1.How can I place an order for TL431CL5T through Aetrix?

Please submit a Request for Quotation (RFQ) for TL431CL5T 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 TL431CL5T reliable?

The price and inventory of TL431CL5T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431CL5T is usually 5 days.

3.What payment methods are accepted for TL431CL5T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431CL5T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL431CL5T?

TL431CL5T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL431CL5T 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 TL431CL5T?

For technical support, including TL431CL5T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431CL5T requirements.

6.How does Aetrix verify that TL431CL5T is sourced from the original manufacturer or authorized distributors?

All TL431CL5T 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 TL431CL5T meets industry standards.

7.What is the process for return or replacement of TL431CL5T?

All TL431CL5T units undergo pre-shipment inspection (PSI). If there is an issue with TL431CL5T, 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 TL431CL5T part is unused and in its original packaging.

Return procedure for TL431CL5T:

1.Submit a request within 90 days.

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

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