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

STMicroelectronics TS3431BIZ

Name: TS3431BIZ
Brand: STMicroelectronics
SKU: TS3431BIZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TS3431BIZ

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

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

Datasheet:: TS3431BIZ.pdf

Description:: IC VREF SHUNT ADJ 0.5% SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,522

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Product details

Overview

TS3431BIZ from STMicroelectronics is a programmable shunt voltage reference with 0.5% initial accuracy at 25°C, adjustable output voltage from 1.24V to 24V via external resistors, ±21mV reference voltage drift over –40°C to +125°C, and sink current capability up to 100mA. It serves as a precision feedback element in isolated DC-DC converters and battery charger regulation circuits.

For engineers reviewing the TS3431BIZ datasheet, TS3431BIZ pinout, TS3431BIZ application, or TS3431BIZ equivalent, key selection criteria include temperature-stable reference voltage (100 ppm/°C TC), low off-state cathode current (≤2 µA at +125°C), dynamic impedance (0.2–0.4 Ω), wideband noise (100 nV/√Hz), and TO-92 package compatibility with legacy through-hole power supply designs.

Technical Context

The TS3431BIZ implements a two-terminal shunt topology where cathode-anode voltage is regulated by internal bandgap-derived reference and error amplifier driving an NPN output stage. Its operation requires external resistor divider to set V_REF, with minimum cathode current of 0.5mA across full temperature range to maintain regulation.

It features guaranteed thermal stability: reference voltage variation is limited to ±21mV over –40°C to +125°C, and temperature coefficient is specified at ≤100 ppm/°C. Dynamic impedance remains below 0.4Ω from 1mA to 100mA cathode current, enabling stable loop response in SMPS feedback networks.

Key Specifications

Parameter	Value and Actual Design Meaning
Initial Accuracy	±0.5% at 25°C - ensures precise voltage setting without trimming in production
Output Voltage Range	1.24V to 24V - supports wide-range feedback scaling for diverse power topologies
Temp. Coefficient	≤100 ppm/°C - maintains <±0.3% total drift over industrial temperature range
Sink Current Range	0.5mA to 100mA - enables direct drive of optocoupler LEDs or error amplifier inputs
Dynamic Impedance	0.2–0.4Ω - provides low AC impedance for high-frequency loop stability
Wideband Noise	100 nV/√Hz (1–100 kHz) - minimizes noise injection into sensitive feedback paths
Off-State Current	≤2000 nA at +125°C - reduces standby power loss in battery-backed systems

Pinout & Package

TS3431BIZ uses the TO-92 plastic package (3-pin, through-hole), with standardized pinout: Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Reference (adjust) terminal. This configuration enables direct replacement of TL431 in existing through-hole designs requiring shunt reference functionality.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Pin 1)	Current return path	Connected to system ground or low-side return; sets reference node potential
Cathode (Pin 2)	Regulated output node	Sinks current to maintain V_KA = V_REF × (1 + R1/R2); drives optocoupler or error amp
Reference (Pin 3)	Feedback input	Connects to resistor divider midpoint; senses scaled output for regulation control

Key Features

Feature	Design Value
Guaranteed temp. stability	±21mV over –40°C to +125°C - eliminates need for external compensation in harsh environments
Low reference current	≤1.5 µA at 25°C - minimizes loading on resistor divider, improving accuracy and power efficiency
High ESD robustness	2 kV HBM - withstands handling stress in manual assembly and field service
Legacy-compatible footprint	TO-92 mechanical outline matches TL431 - enables drop-in replacement without PCB redesign

Applications

Switch Mode Power Supply

Battery Charger

Use Scenario: Primary-side feedback in isolated flyback converters using optocoupler-coupled regulation.

IC Role / Device Role / Timing Role: Shunt reference providing precise voltage threshold to drive optocoupler LED current.

Use Value: Enables ±1% output regulation across line/load/temperature with no secondary-side sensing.

Use Scenario: Constant-voltage stage control in multi-stage Li-ion battery chargers.

IC Role / Device Role / Timing Role: Precision voltage reference for comparator-based CV loop termination.

Use Value: Ensures cell voltage accuracy within ±5mV, preventing overcharge and extending cycle life.

Instrumentation

Computer Power Management

Use Scenario: Calibration reference in portable multimeters and data loggers.

IC Role / Device Role / Timing Role: Stable 2.5V or 5V reference source for ADC and DAC biasing.

Use Value: Delivers <100 ppm/°C drift, supporting 16-bit measurement accuracy without recalibration.

Use Scenario: +3.3V and +5V rail monitoring in ATX motherboard VRM supervision circuits.

IC Role / Device Role / Timing Role: Threshold detector for power-good signaling and OVP protection.

Use Value: Provides fast, accurate trip point with <1µs response time to prevent CPU damage during overvoltage events.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACZ	±1% initial accuracy, higher 2.5V fixed reference (non-programmable), TO-92 package	Limited to 2.5V output; lacks adjustable range; lower temp. stability (±50 ppm/°C)	Select when fixed 2.5V reference suffices and cost is primary constraint
LM431ACZ	±1% accuracy, same TO-92 package, but higher min. cathode current (1mA) and wider V_KA range (2–36V)	Higher startup current may require larger bias resistor; less suitable for ultra-low-power battery systems	Prefer for higher-voltage rails (>24V) where extended V_KA range is needed

Compared with TL431ACZ and LM431ACZ, TS3431BIZ offers tighter initial tolerance (±0.5%), superior temperature coefficient (≤100 vs ≥200 ppm/°C), and lower minimum operating current (0.5mA vs 1mA), making it optimal for precision, low-power, and wide-temperature industrial power supplies.

Availability

TS3431BIZ is available at Aetrix Electronics and suitable for switch mode power supplies, battery chargers, instrumentation systems, and computer power management requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for TS3431BIZ 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The TS3431 series belongs to ST's precision analog portfolio, engineered specifically for high-reliability voltage reference applications in industrial power conversion, where long-term stability, wide temperature operation, and legacy package compatibility are critical design requirements.

FAQ

What is the maximum cathode-to-anode voltage rating for TS3431BIZ?

The absolute maximum cathode-to-anode voltage (V_KA) is 25V. Operation above this level risks permanent device failure. In practice, the device regulates only up to 24V under normal conditions, with derating recommended above 85°C ambient to maintain junction temperature below 150°C.

Can TS3431BIZ replace TL431 in existing TO-92 designs?

Yes - TS3431BIZ shares identical TO-92 pinout (Anode–Cathode–Reference), mechanical dimensions, and functional behavior. Its ±0.5% accuracy and improved temperature stability provide immediate performance uplift without layout changes, provided external resistor values are verified for target V_OUT.

How does the reference input current (I_REF) affect accuracy in precision applications?

I_REF flows into the reference pin and creates voltage drop across upper divider resistor, introducing gain error. At 1.5µA max and typical R1=10kΩ, this adds ≤15mV offset - corrected by reducing R1 or using I_REF-compensated divider design per ST AN2175.

Is TS3431BIZ suitable for battery-operated equipment with strict quiescent current limits?

Yes - its off-state cathode current is ≤500nA at 25°C and ≤2µA at +125°C, and reference current is ≤1.5µA. Combined with minimal bias resistor power, it supports multi-year battery life in always-on monitoring circuits such as smoke detectors and remote sensors.

TS3431BIZ Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

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

Series:: -

Packaging:: Tube

Product Status:: Obsolete

Reference Type:: Shunt

Output Type:: Adjustable

Voltage - Output (Min/Fixed):: 1.24V

Voltage - Output (Max):: 24 V

Current - Output:: 100 mA

Tolerance:: ±0.5%

Temperature Coefficient:: 100ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 500 µA

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

TS3431BIZ FAQ

1.How can I place an order for TS3431BIZ through Aetrix?

Please submit a Request for Quotation (RFQ) for TS3431BIZ 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 TS3431BIZ reliable?

The price and inventory of TS3431BIZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TS3431BIZ is usually 5 days.

3.What payment methods are accepted for TS3431BIZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TS3431BIZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TS3431BIZ?

TS3431BIZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TS3431BIZ 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 TS3431BIZ?

For technical support, including TS3431BIZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TS3431BIZ requirements.

6.How does Aetrix verify that TS3431BIZ is sourced from the original manufacturer or authorized distributors?

All TS3431BIZ 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 TS3431BIZ meets industry standards.

7.What is the process for return or replacement of TS3431BIZ?

All TS3431BIZ units undergo pre-shipment inspection (PSI). If there is an issue with TS3431BIZ, 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 TS3431BIZ part is unused and in its original packaging.

Return procedure for TS3431BIZ:

1.Submit a request within 90 days.

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

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