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

STMicroelectronics TS431AIZT

Name: TS431AIZT
Brand: STMicroelectronics
SKU: TS431AIZT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TS431AIZT

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: TS431AIZT.pdf

Description:: IC VREF SHUNT ADJ 1% TO92-3

Quantity:: RFQ Add To RFQ list

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Inventory:2,433

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Product details

Overview

TS431AIZT from STMicroelectronics is an AEC-Q100-qualified, adjustable shunt voltage reference IC in SOT23-5 package, delivering 1.24 V to 6 V output with 1% initial precision, 0.2 Ω output impedance, and stable operation down to 60 µA cathode current. It serves as a precision feedback element in automotive-grade 3.3 V switching power supplies driving optocouplers.

For engineers reviewing the TS431AIZT datasheet, TS431AIZT pinout, TS431AIZT application, or TS431AIZT equivalent, key selection criteria include its low-voltage regulation capability (1.24 V min), automotive temperature range (−40 °C to +125 °C), 100 ppm/°C tempco, and compatibility with capacitive loads without external compensation.

Technical Context

The TS431AIZT implements a three-terminal shunt topology where output voltage is set externally via two resistors across the reference (REF), cathode (K), and anode (A) terminals. Its internal bandgap reference and error amplifier enable precise voltage regulation independent of input voltage variations above V_ref.

It operates with cathode current from 60 µA to 30 mA and maintains stability across full automotive temperature range (−40 °C to +125 °C). The device exhibits low dynamic output impedance (0.2 Ω typ.) and negligible phase shift up to 1 MHz, supporting fast transient response in closed-loop feedback systems.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage Range	1.24 V to 6 V - programmable via external resistor divider for flexible feedback design
Initial Precision	±1% at 25 °C - ensures tight output tolerance without calibration in production
Tempco	100 ppm/°C - limits drift to ±12.5 mV over −40 °C to +125 °C range
Cathode Current Range	60 µA to 30 mA - supports ultra-low-power standby modes and high-current regulation
Output Impedance	0.2 Ω typical - minimizes load-induced voltage deviation in dynamic conditions
ESD Rating	HBM: 2 kV - meets automotive board-level ESD robustness requirements
Operating Temp	−40 °C to +125 °C - qualified per AEC-Q100 Grade 1 for under-hood applications

Pinout & Package

SOT23-5 plastic micropackage (5-pin, 1.9 mm × 1.6 mm footprint), lead-free and RoHS-compliant per ECOPACK® specifications.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (REF)	Reference Input	High-impedance node connected to internal bandgap reference; sets output voltage with external resistors
Pin 2 (A)	Anode	Ground return path; must be connected to system GND for proper shunt operation
Pin 3 (K)	Cathode	Regulated output node; sinks current to maintain V_KA = V_ref × (1 + R1/R2)
Pin 4 (NC)	No Connect	Internally unconnected; must remain floating or tied to GND per layout guidelines
Pin 5 (NC)	No Connect	Internally unconnected; must remain floating or tied to GND per layout guidelines

Key Features

Feature	Design Value
Adjustable Output Voltage	Set precisely between 1.24 V and 6 V using only two external resistors - eliminates need for multiple fixed-reference SKUs
Low Minimum Cathode Current	60 µA regulation threshold - enables use in energy-sensitive auxiliary rails and standby circuits
Capacitive Load Stability	Stable with any value of output capacitance - removes need for series resistance or compensation networks
Automotive Qualification	AEC-Q100 Grade 1 certified in SOT23-5 - validated for under-hood deployment without derating
Low Output Impedance	0.2 Ω typical - ensures <1 mV droop under 10 mA load step, critical for optocoupler bias accuracy

Applications

Automotive DC-DC Feedback

Industrial SMPS Regulation

Use Scenario: Closed-loop voltage regulation in 12 V–48 V automotive buck converters supplying infotainment and ADAS subsystems.

IC Role / Device Role / Timing Role: Shunt reference providing precise feedback to primary-side controller via optocoupler isolation barrier.

Use Value: 1% initial accuracy and 100 ppm/°C tempco ensure output stays within ±2% over full temperature and lifetime, meeting ISO 16750-2 requirements.

Use Scenario: Secondary-side voltage sensing in industrial 24 V isolated flyback supplies powering PLC I/O modules.

IC Role / Device Role / Timing Role: Adjustable shunt reference setting regulated 5 V or 3.3 V output, interfacing with TLV272 comparator for overvoltage protection.

Use Value: 60 µA minimum cathode current allows reliable regulation even during light-load burst-mode operation, reducing no-load power loss.

Optocoupler Biasing

Programmable Threshold Detection

Use Scenario: Biasing PC817 or SFH615A optocouplers in isolated feedback paths of AC-DC adapters.

IC Role / Device Role / Timing Role: Precision current sink establishing stable LED forward current proportional to output voltage.

Use Value: 0.2 Ω output impedance prevents LED current variation due to supply ripple, improving loop gain stability by >6 dB.

Use Scenario: Configurable overvoltage lockout (OVL) in battery management systems monitoring 3S–4S Li-ion packs.

IC Role / Device Role / Timing Role: Adjustable reference input to LM393 comparator, triggering shutdown when cell voltage exceeds 4.25 V.

Use Value: 1.24 V to 6 V range enables direct scaling to pack voltage without additional dividers, reducing component count and BOM cost.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACDT	Fixed 2.5 V reference; requires external resistor network to emulate adjustable behavior; higher 100 µA min cathode current	Lacks native adjustability; less suitable for <3 V outputs or space-constrained designs	Select only if fixed 2.5 V output suffices and board area permits added resistors
MAX6008AEUR+T	Fixed-output (1.25 V) series reference; 30 ppm/°C tempco; 5 µA quiescent current; not shunt-based	Cannot sink current; incompatible with optocoupler feedback topologies requiring shunt configuration	Choose only for low-power, non-isolated, series-regulator applications where sinking capability is unnecessary

Compared with TL431ACDT and MAX6008AEUR+T, TS431AIZT uniquely combines true adjustability, shunt topology, automotive qualification, and sub-100 µA regulation-making it the only drop-in solution for AEC-Q100-compliant isolated feedback loops requiring <3 V setpoints.

Availability

TS431AIZT is available at Aetrix Electronics and suitable for automotive power conversion, industrial SMPS design, optocoupler-based feedback systems, and programmable voltage monitoring requiring stable component supply across extended temperature ranges.

Supply support for TS431AIZT 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, analog ICs, power devices, and sensors for automotive, industrial, and consumer markets.

The TS431 belongs to ST's precision analog voltage reference product line, engineered specifically for automotive-grade isolated power supply feedback and industrial control applications demanding high accuracy, low power, and robust thermal performance.

FAQ

What is the minimum cathode current required for regulation in TS431AIZT?

The TS431AIZT achieves stable regulation at a minimum cathode current of 60 µA, verified across −40 °C to +125 °C. This enables reliable operation in ultra-low-power standby modes and light-load conditions common in automotive body control modules and IoT edge nodes.

Can TS431AIZT replace TL431 in existing designs?

Yes, TS431AIZT is pin-compatible with TL431 in SOT23-5 footprint (REF, A, K pins aligned), but requires verification of resistor values due to its lower 1.24 V reference voltage versus TL431's 2.495 V. No changes needed for cathode current or thermal design.

Is TS431AIZT qualified for automotive applications?

Yes - TS431AIZT is AEC-Q100 Grade 1 qualified (−40 °C to +125 °C) and manufactured in ST's automotive-certified facilities. The "Y" suffix in ordering codes (e.g., TS431AIYLT) denotes full automotive qualification; TS431AIZT carries identical qualification in TO-92 form factor.

Does TS431AIZT require external compensation for stability?

No - TS431AIZT is internally compensated and remains stable with any capacitive load, including large bulk electrolytics or ceramic arrays used in SMPS output filtering. No series resistor or RC network is needed, simplifying layout and reducing BOM count.

TS431AIZT Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

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:: ±1%

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:: Through Hole

Supplier Device Package:: TO-92-3

TS431AIZT FAQ

1.How can I place an order for TS431AIZT through Aetrix?

Please submit a Request for Quotation (RFQ) for TS431AIZT 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 TS431AIZT reliable?

The price and inventory of TS431AIZT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TS431AIZT is usually 5 days.

3.What payment methods are accepted for TS431AIZT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TS431AIZT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TS431AIZT?

TS431AIZT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TS431AIZT 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 TS431AIZT?

For technical support, including TS431AIZT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TS431AIZT requirements.

6.How does Aetrix verify that TS431AIZT is sourced from the original manufacturer or authorized distributors?

All TS431AIZT 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 TS431AIZT meets industry standards.

7.What is the process for return or replacement of TS431AIZT?

All TS431AIZT units undergo pre-shipment inspection (PSI). If there is an issue with TS431AIZT, 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 TS431AIZT part is unused and in its original packaging.

Return procedure for TS431AIZT:

1.Submit a request within 90 days.

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

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