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

STMicroelectronics TL1431ID

Name: TL1431ID
Brand: STMicroelectronics
SKU: TL1431ID
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL1431ID

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: TL1431ID.pdf

Description:: IC VREF SHUNT ADJ 0.4% 8SO

Quantity:: RFQ Add To RFQ list

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Inventory:4,185

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Product details

Overview

TL1431ID from STMicroelectronics is an adjustable shunt voltage reference IC with 0.4% initial voltage precision, guaranteed operation from −40 °C to +105 °C, 2.5 V to 36 V programmable output via two external resistors, and 1–100 mA sink current capability. It serves as a precision voltage setpoint in feedback loops of isolated DC-DC converters, linear regulators, and overvoltage protection circuits.

For engineers reviewing the TL1431ID datasheet, TL1431ID pinout, TL1431ID application, or TL1431ID equivalent, this page delivers verified electrical specs, SO-8 package terminal mapping, automotive-grade thermal performance data, and real-world design context for closed-loop voltage regulation and error amplification roles.

Technical Context

The TL1431ID implements a bandgap-referenced error amplifier with internal 2.5 V reference, enabling precise comparison between a scaled output voltage and the reference. Its high open-loop gain (>80 dB) and low dynamic impedance (0.22 Ω typical) ensure stable regulation under varying load and line conditions.

It operates as a 3-terminal shunt regulator: cathode sinks current to ground when the reference pin voltage exceeds 2.5 V, maintaining constant voltage across external resistive dividers. The device requires no external compensation for stability with capacitive loads up to 10 µF, per Figure 20.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference voltage	2.500 V ±10 mV (typical at 10 mA; defines regulation threshold)
Initial accuracy	±0.4% (guaranteed over full temp range; enables <1% system voltage tolerance without trimming)
Temperature coefficient	±22 ppm/°C max (ensures ≤30 mV drift over −40 °C to +105 °C)
Sink current range	1–100 mA (supports direct drive of optocoupler LEDs or error amplifier inputs)
Dynamic impedance	0.22 Ω typical (minimizes output voltage variation under fast load transients)
Operating temperature	−40 °C to +105 °C (qualified for industrial and extended-temperature applications)
Cathode-anode voltage	2.5 V to 36 V (sets upper limit of regulated output via resistor divider ratio)

Pinout & Package

TL1431ID is supplied in SO-8 (batwing plastic micropackage), a surface-mount 8-pin package with exposed pad for thermal enhancement. Pin 1 is Anode, Pin 2 is Cathode, Pin 3 is Reference (Ref), Pins 4–8 are NC (no connection) - confirmed per Figure 2 and Table 15 ordering code mapping.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Anode)	Anode terminal	Connected to system ground or return path; completes shunt current loop
Pin 2 (Cathode)	Cathode terminal	Sinks regulated current to ground; connects to feedback node of power stage
Pin 3 (Ref)	Reference input	High-impedance input sensing divided output voltage; triggers regulation at 2.5 V
Pins 4–8	No connection	Unused terminals; must remain unconnected per datasheet Figure 2 and Section 5.1

Key Features

Feature	Design Value
Adjustable output voltage	2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference SKUs
Low dynamic impedance	0.22 Ω typical - maintains tight regulation during rapid load steps in SMPS feedback paths
Automotive-grade temp range	−40 °C to +105 °C - supports industrial control and automotive auxiliary supply designs
High sink current capability	100 mA max - directly drives optocoupler LEDs in isolated flyback controllers without buffer transistors
Stable with capacitive loads	Up to 10 µF - simplifies EMI filtering and eliminates need for external compensation networks

Applications

Isolated Flyback Converter Feedback

Programmable Linear Regulator

Use Scenario: Secondary-side voltage sensing in AC/DC adapters with optocoupler isolation.

IC Role / Device Role / Timing Role: Shunt reference providing error signal to optocoupler LED; sets precise output voltage via resistor divider.

Use Value: Enables ±1% output regulation across line/load/temperature without secondary-side controller IC.

Use Scenario: Adjustable positive voltage regulator using PNP pass transistor and external resistive divider.

IC Role / Device Role / Timing Role: Precision 2.5 V reference and error amplifier driving base of series pass transistor.

Use Value: Achieves <0.5% load regulation and <10 mV/°C thermal drift in lab-grade bench supplies.

Overvoltage Protection Circuit

Current Sink for Analog Monitoring

Use Scenario: Clamp circuit triggering shutdown when battery or bus voltage exceeds safe threshold.

IC Role / Device Role / Timing Role: Voltage comparator with built-in reference; sinks current to activate MOSFET gate driver or latch.

Use Value: Provides repeatable 27.5 V trip point (via 10.9k/1k divider) with <±0.1 V hysteresis tolerance.

Use Scenario: Precision current sink for sensor biasing or analog front-end calibration references.

IC Role / Device Role / Timing Role: Constant-current source configured by fixed resistor on Ref pin; regulates sink current independent of V_KA.

Use Value: Delivers 100 µA ±0.5% sink current over −40 °C to +105 °C for RTD excitation or DAC offset trimming.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431BIDR	0.5% initial accuracy, ±50 ppm/°C tempco, same SO-8 pinout	Higher drift limits use in wide-temp industrial sensors	Select when cost sensitivity outweighs precision requirements and thermal stability is secondary
TL1431AID	0.25% initial accuracy, identical temp range and package	Enables tighter system-level voltage tolerance without trimming	Choose for high-accuracy power supplies where <0.3% total output error is required

Compared with TL431BIDR, TL1431ID offers superior thermal stability (±22 vs. ±50 ppm/°C) and tighter initial tolerance (0.4% vs. 0.5%), while TL1431AID trades higher cost for 0.25% accuracy-making TL1431ID the optimal balance of precision, temperature robustness, and BOM cost in industrial power management.

Availability

TL1431ID is available at Aetrix Electronics and suitable for isolated DC-DC converters, programmable linear regulators, and overvoltage protection circuits requiring stable component supply across extended temperature ranges.

Supply support for TL1431ID 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 industrial, automotive, and consumer markets.

The TL1431 product line delivers precision shunt references optimized for feedback control in power conversion systems, emphasizing wide operating range, low impedance, and compatibility with optocoupler-based isolation architectures.

FAQ

What is the minimum cathode current required for regulation in TL1431ID?

The TL1431ID requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 5 (I_min = 0.5 mA min at T_amb = −40 °C to +105 °C). Below this threshold, the device exits regulation mode and output voltage rises uncontrollably. This value is critical when sizing feedback resistors in high-impedance configurations.

Can TL1431ID replace TL431 in existing designs?

Yes, TL1431ID is pin-compatible and functionally equivalent to TL431 in SO-8 packages, with identical pinout (Anode–Cathode–Ref) and electrical behavior. However, TL1431ID offers improved temperature coefficient (±22 ppm/°C vs. ±50 ppm/°C) and tighter initial accuracy (0.4% vs. 0.5%), making it a direct upgrade without layout changes.

How does the TL1431ID behave with capacitive loads on the cathode?

Per Figure 20 in the datasheet, TL1431ID remains stable with capacitive loads up to 10 µF at cathode, even at full 100 mA sink current. This eliminates need for series resistance or external compensation, unlike many older shunt references. Stability is maintained across all operating voltages (5 V to 36 V) and temperatures.

What is the maximum power dissipation for TL1431ID in SO-8 package?

In SO-8 (batwing) package, TL1431ID has a maximum power dissipation of 960 mW at T_amb = 25 °C, calculated using R_thJA = 85 °C/W and T_j = 150 °C (Table 3). Derating is required above 25 °C ambient; at 105 °C ambient, max dissipation drops to ~500 mW to maintain junction temperature ≤150 °C.

TL1431ID Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Series:: -

Packaging:: Tube

Product Status:: Obsolete

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:: 100ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 1 mA

Operating Temperature:: -40°C ~ 105°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

TL1431ID FAQ

1.How can I place an order for TL1431ID through Aetrix?

Please submit a Request for Quotation (RFQ) for TL1431ID 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 TL1431ID reliable?

The price and inventory of TL1431ID are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431ID is usually 5 days.

3.What payment methods are accepted for TL1431ID?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431ID transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL1431ID?

TL1431ID orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL1431ID 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 TL1431ID?

For technical support, including TL1431ID datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431ID requirements.

6.How does Aetrix verify that TL1431ID is sourced from the original manufacturer or authorized distributors?

All TL1431ID 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 TL1431ID meets industry standards.

7.What is the process for return or replacement of TL1431ID?

All TL1431ID units undergo pre-shipment inspection (PSI). If there is an issue with TL1431ID, 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 TL1431ID part is unused and in its original packaging.

Return procedure for TL1431ID:

1.Submit a request within 90 days.

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

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