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

STMicroelectronics TS431ILT

Name: TS431ILT
Brand: STMicroelectronics
SKU: TS431ILT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TS431ILT

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: SC-74A, SOT-753

Datasheet:: TS431ILT.pdf

Description:: IC VREF SHUNT ADJ 2% SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:2,684

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Product details

Overview

TS431ILT from STMicroelectronics is an AEC-Q100 qualified, adjustable shunt voltage reference IC in SOT23-5 package, delivering 2% initial voltage precision across 1.24–6 V output range with 100 ppm/°C temperature coefficient and 0.2 Ω output impedance. It operates down to 60 µA cathode current and supports automotive-grade 3.3 V switching power supply regulation via optocoupler feedback.

For engineers reviewing the TS431ILT datasheet, TS431ILT pinout, TS431ILT application, or TS431ILT equivalent, this page provides verified electrical parameters, thermal behavior at −40 °C to +125 °C, stability under capacitive loads, ESD ratings (2 kV HBM), and design guidance for low-current shunt reference implementation in isolated DC-DC feedback loops.

Technical Context

The TS431ILT implements a three-terminal bandgap-based shunt reference architecture with internal reference voltage (V_REF = 1.24 V) and adjustable output via external resistor divider. Its low 60 µA minimum cathode current enables operation in ultra-low-power feedback paths where TL431 variants fail.

It features inherently stable loop dynamics-no external compensation required-and maintains ≤21 mV total output voltage drift over −40 °C to +125 °C. The device's 0.2 Ω static impedance ensures minimal load regulation error even at 30 mA cathode current.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage Range	1.24 V to 6 V - set by external R1/R2 divider; enables precise regulation of 3.3 V, 5 V, or custom rails
Initial Voltage Precision	2% - specified at 25 °C; defines worst-case output deviation before trimming or calibration
Tempco	100 ppm/°C - limits output drift to ±12.5 mV over −40 °C to +125 °C (ΔT = 165 °C)
Cathode Current Range	60 µA to 30 mA - supports operation in standby mode (µA-level) and full-load regulation (mA-level)
Output Impedance	0.2 Ω - ensures <1 mV load regulation error for 5 mA load step changes
ESD Rating	2 kV HBM - meets automotive board-level robustness requirements without additional protection
Operating Temp Range	−40 °C to +125 °C - qualified per AEC-Q100 Grade 1 for under-hood and powertrain applications

Pinout & Package

SOT23-5 plastic micropackage (ECOPACK® compliant), 1.45 mm × 1.75 mm footprint, 1.3 mm max height, with exposed pad not connected internally.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (K)	Cathode	Main current sink terminal; connects to regulated rail node and optocoupler anode in flyback feedback
Pin 2 (A)	Anode	Reference ground return; tied to system GND or isolated secondary ground
Pin 3 (REF)	Reference Input	Sense node for resistor divider; draws only 70–160 nA, enabling high-R bias networks
Pin 4 (NC)	No Connect	Internally unconnected; must be left floating or tied to A for mechanical stability
Pin 5 (NC)	No Connect	Internally unconnected; must be left floating or tied to A for mechanical stability

Key Features

Feature	Design Value
Low-voltage start-up	Operates down to 1.24 V cathode-anode differential - enables use in 1.8 V–3.3 V auxiliary supplies where TL431 fails
Capacitive load immunity	Stable with any value of output capacitance - eliminates need for series resistance or compensation network
Ultra-low I_MIN	60 µA minimum cathode current - reduces standby power in always-on systems by >5× vs. TL431 (1 mA typical)
Automotive qualification	AEC-Q100 Grade 1 certified in SOT23-5 - validated for 15-year lifetime in harsh thermal cycling environments
Low noise performance	200 nV/√Hz input noise at 10 kHz - preserves signal integrity in precision sensing and ADC reference paths

Applications

AC-DC Flyback Power Supply

Automotive Body Control Module

Use Scenario: Isolated 12 V → 3.3 V flyback converter with optocoupler feedback loop.

IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 3.3 V sense point to optocoupler LED anode.

Use Value: Enables ±2% output regulation across line/load/temp with no external compensation, reducing BOM count by one capacitor and one resistor.

Use Scenario: Low-power 5 V rail regulation in door module MCU power domain.

IC Role / Device Role / Timing Role: Adjustable shunt reference setting 5 V output via resistor divider on secondary side of isolated DC-DC.

Use Value: Meets AEC-Q100 Grade 1 temp range (−40 °C to +125 °C) and 2 kV HBM ESD without derating or shielding.

Industrial PLC I/O Module

Medical Patient Monitor Power Rail

Use Scenario: 24 V input, 5 V/3.3 V dual-output isolated buck-boost with feedback stabilization.

IC Role / Device Role / Timing Role: Primary-side shunt reference controlling PWM duty cycle via optocoupler feedback path.

Use Value: 60 µA I_MIN allows reliable start-up during brown-out conditions where input dips to 15 V.

Use Scenario: Battery-backed 3.3 V supply for analog front-end in portable ECG unit.

IC Role / Device Role / Timing Role: Precision voltage reference for ADC reference buffer and sensor excitation circuitry.

Use Value: 100 ppm/°C tempco ensures <±0.5% reference drift over patient ambient range (15–40 °C), critical for diagnostic accuracy.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACDBVR	Higher 1 mA minimum cathode current; 2% precision; no AEC-Q100 qualification	Not suitable for automotive or ultra-low-power designs requiring <100 µA start-up	Select when cost is primary concern and operating temperature stays within −25 °C to +85 °C
MAX6008AEUR+T	Fixed 2.048 V output; 0.5% precision; 75 ppm/°C tempco; SOT23-3 package	Lacks adjustability; requires redesign of resistor network; lower thermal drift but inflexible voltage choice	Select when fixed 2.048 V reference is acceptable and higher precision outweighs need for programmability

Compared with TL431ACDBVR and MAX6008AEUR+T, the TS431ILT uniquely combines automotive qualification, adjustable output, sub-100 µA start-up capability, and uncompromised stability-making it the only viable option for AEC-Q100-compliant, optocoupler-driven flyback controllers in constrained thermal and power envelopes.

Availability

TS431ILT is available at Aetrix Electronics and suitable for AC-DC power supplies, automotive body electronics, industrial PLC I/O modules, and medical battery-powered devices requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for TS431ILT 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, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The TS431ILT belongs to ST's precision analog voltage reference product line, engineered specifically for automotive-grade isolated power conversion and high-reliability feedback control where low quiescent current, wide temperature operation, and AEC-Q100 compliance are mandatory.

FAQ

What is the minimum cathode current required for regulation in TS431ILT?

The TS431ILT requires a minimum cathode current of 60 µA to maintain regulation, verified across −40 °C to +125 °C. This value is measured at V_KA = V_REF and is significantly lower than TL431 (typically 1 mA), enabling reliable operation in ultra-low-power standby modes and energy-harvesting applications.

Can TS431ILT replace TL431 in existing designs without modification?

No direct drop-in replacement is guaranteed. While pin-compatible in SOT23-5 layout, TS431ILT has different internal gain and dynamic response. Designs using TL431 with marginal phase margin may require re-evaluation of optocoupler CTR and compensation network due to TS431ILT's lower I_REF (70–160 nA vs. ~2 µA) and faster settling.

Does TS431ILT require external capacitors for stability?

No external capacitors are required for stability. The TS431ILT is characterized as "typically stable for any capacitive loads" per its datasheet, eliminating the need for series resistance or RC compensation networks commonly used with TL431 in high-C_OUT applications like LDO post-regulation.

What does the 'L272' marking on TS431ILT indicate?

The 'L272' top-side marking identifies the TS431ILT as the 2% precision grade in SOT23-5 tape-and-reel packaging. It is distinct from L271 (1%) and L270 (0.5%), and confirms AEC-Q100 qualification per ordering code TS431ILT in Table 8 of the official ST datasheet DocID5558 Rev 12.

TS431ILT 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):: 1.24V

Voltage - Output (Max):: 6 V

Current - Output:: 30 mA

Tolerance:: ±2%

Temperature Coefficient:: 100ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 60 µA

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

TS431ILT FAQ

1.How can I place an order for TS431ILT through Aetrix?

Please submit a Request for Quotation (RFQ) for TS431ILT 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 TS431ILT reliable?

The price and inventory of TS431ILT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TS431ILT is usually 5 days.

3.What payment methods are accepted for TS431ILT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TS431ILT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TS431ILT?

TS431ILT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TS431ILT 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 TS431ILT?

For technical support, including TS431ILT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TS431ILT requirements.

6.How does Aetrix verify that TS431ILT is sourced from the original manufacturer or authorized distributors?

All TS431ILT 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 TS431ILT meets industry standards.

7.What is the process for return or replacement of TS431ILT?

All TS431ILT units undergo pre-shipment inspection (PSI). If there is an issue with TS431ILT, 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 TS431ILT part is unused and in its original packaging.

Return procedure for TS431ILT:

1.Submit a request within 90 days.

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

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