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

STMicroelectronics TL1431AID

Name: TL1431AID
Brand: STMicroelectronics
SKU: TL1431AID
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TL1431AID

Manufacturer:: STMicroelectronics

Category:: Voltage Reference

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

Datasheet:: TL1431AID.pdf

Description:: IC VREF SHUNT ADJ 0.25% 8SO

Quantity:: RFQ Add To RFQ list

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Inventory:2,764

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Product details

Overview

TL1431AID from STMicroelectronics is an adjustable shunt voltage reference IC with 0.25% 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 feedback element in isolated DC-DC converters, linear regulators, and overvoltage protection circuits.

For engineers reviewing the TL1431AID datasheet, TL1431AID pinout, TL1431AID application, or TL1431AID equivalent, this page delivers verified electrical parameters, SO-8 package terminal mapping, automotive-grade thermal performance data, and real-world design context for closed-loop voltage regulation systems.

Technical Context

The TL1431AID implements a bandgap-based reference core with internal error amplifier and NPN output stage, enabling precise cathode-to-anode voltage control across wide current and temperature ranges. Its dynamic impedance of 0.2 Ω (typ.) and ±13 ppm/°C temperature coefficient support stable regulation in feedback loops with capacitive loads up to 10 µF.

It operates as a 3-terminal shunt regulator: the REF pin senses voltage via external resistor divider, the CATHODE sinks current to maintain V_REF × (1 + R1/R2), and the ANODE connects to system ground or return path. No external compensation is required for stability with ≤10 nF load capacitance.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference voltage accuracy	±0.25% at 25 °C - enables <±9 mV error in 3.3 V or 5 V feedback networks without trimming.
Output voltage range	2.5 V to 36 V - set by external R1/R2 divider; supports regulation in 12 V, 24 V, and 48 V industrial power rails.
Sink current range	1 mA to 100 mA - sufficient to drive optocoupler LEDs in flyback controllers or bias error amplifiers in LDOs.
Dynamic impedance	0.2 Ω (typ.) - ensures <20 mV output deviation under 100 mA load transients, critical for tight-tolerance regulation.
Temp. coefficient	±13 ppm/°C - guarantees <±0.33 mV/°C drift over –40 °C to +105 °C, meeting automotive AEC-Q100 Grade 2 requirements.
Operating temperature	–40 °C to +105 °C - qualified for under-hood automotive modules, industrial PLC I/O, and telecom power supplies.
Max. cathode-anode voltage	36 V - allows direct use in 24 V systems with margin; absolute max rating is 37 V.

Pinout & Package

TL1431AID is supplied in SO-8 "batwing" plastic micropackage (ECOPACK® compliant), offering improved thermal dissipation (R_thJA = 85 °C/W) versus TO-92 or SOT variants. Pin 1 is ANODE, Pin 2 is CATHODE, Pin 3 is REF, Pins 4–8 are NC (no connect) per Figure 2 of ST's DocID5286 Rev 9.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (ANODE)	Reference ground return	Connects to system ground or low-side return path; carries full cathode current minus reference input current.
Pin 2 (CATHODE)	Current sink output	Sinks regulated current to maintain V_REF at divider node; must be connected to high-side of feedback divider or optocoupler anode.
Pin 3 (REF)	Reference input sense	High-impedance (2.5 µA typ.) input sensing voltage at divider junction; sets regulation point via R1/R2 ratio.
Pins 4–8 (NC)	No connection	Internally unconnected; must remain floating or grounded per layout best practices-no routing or soldering required.

Key Features

Feature	Design Value
Adjustable output voltage	Programmable from 2.5 V to 36 V using only two external resistors-eliminates need for multiple fixed-reference SKUs.
Low dynamic impedance	0.2 Ω typical ensures minimal output voltage perturbation during fast load steps, improving transient response in SMPS feedback loops.
Automotive-grade temp. range	–40 °C to +105 °C operation with ±0.25% initial accuracy meets AEC-Q100 stress test requirements for engine control units.
High sink current capability	100 mA max cathode current drives standard PC817/PC818 optocouplers directly-no external transistor needed in isolated flyback designs.
Stability with capacitive loads	Remains stable with ≥10 nF load capacitance-supports direct connection to error amplifier inputs without phase compensation.

Applications

Isolated Flyback Converter Feedback

Programmable Linear Regulator Reference

Use Scenario: TL1431AID provides secondary-side voltage sensing in 24 V input, 5 V/3 A isolated flyback converter for industrial IoT gateway.

IC Role / Device Role / Timing Role: Shunt reference IC acting as precision voltage comparator and current sink in optocoupler-coupled feedback loop.

Use Value: Enables ±1% output regulation across line/load/temperature with no secondary-side LDO-reducing BOM count and board area.

Use Scenario: Used in adjustable 3.3 V to 12 V linear regulator for FPGA I/O bank supply, where fine-grained voltage tuning is required.

IC Role / Device Role / Timing Role: Adjustable shunt reference setting base-emitter voltage of pass transistor in series regulator topology.

Use Value: Delivers 0.25% initial accuracy and <10 mV total drift over temperature-meeting FPGA VCCIO tolerance specs without calibration.

Overvoltage Protection Circuit

Current-Limited Voltage Monitor

Use Scenario: Monitors 48 V telecom power rail and triggers crowbar circuit when voltage exceeds 52 V threshold.

IC Role / Device Role / Timing Role: Precision voltage threshold detector with hysteresis implemented via external resistor network on REF pin.

Use Value: Achieves ±0.13 V trip accuracy at 52 V (0.25% × 52 V), ensuring reliable protection without false triggering.

Use Scenario: Controls gate voltage of external MOSFET to limit charging current in 12 V battery backup system.

IC Role / Device Role / Timing Role: Adjustable reference generating error signal for current-sense amplifier in constant-current loop.

Use Value: Supports 0.1 A to 5 A programmable current limit with <±1% accuracy-enabling single design for multiple battery chemistries.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431BIDR	0.5% initial accuracy, same SO-8 package, wider –40 °C to +125 °C range but higher 20 ppm/°C tempco.	Acceptable where ±1% output tolerance suffices and extended temperature margin is prioritized over precision.	Select TL431BIDR if cost sensitivity outweighs need for 0.25% accuracy and tighter tempco in non-automotive industrial use.
MAX6008AEUR+T	Fixed 2.5 V output, SOT23-3 package, 0.1% accuracy, 3 ppm/°C tempco-but not adjustable and lower 15 mA sink current.	Only suitable for fixed-voltage references; cannot replace TL1431AID in programmable-output designs.	Choose MAX6008AEUR+T only for space-constrained 2.5 V reference needs where adjustability is unnecessary and ultra-low drift is critical.

Compared with TL431BIDR, TL1431AID offers superior initial accuracy and lower temperature drift for tighter regulation, while MAX6008AEUR+T trades adjustability for ultra-stable fixed output-making TL1431AID the optimal choice for programmable, automotive-grade shunt regulation.

Availability

TL1431AID is available at Aetrix Electronics and suitable for isolated DC-DC converters, programmable linear regulators, overvoltage protection circuits, and current-limited voltage monitors requiring stable component supply across automotive, industrial, and telecom power designs.

Supply support for TL1431AID 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.

TL1431AID belongs to ST's precision analog voltage reference product line, engineered specifically for high-reliability feedback control in isolated power conversion and safety-critical regulation applications.

FAQ

What is the minimum cathode current required for regulation in TL1431AID?

The TL1431AID requires a minimum cathode current of 0.5 mA (typ.) to maintain regulation, as specified in Table 4 of ST's DocID5286 Rev 9. This value increases slightly at temperature extremes, reaching 0.6 mA maximum over –40 °C to +105 °C. Below this threshold, the device exits regulation and V_KA rises toward the input voltage.

Can TL1431AID replace TL431 in existing designs?

Yes, TL1431AID is pin-compatible with TL431 in SO-8 packages and shares identical electrical behavior, including REF/CATHODE/ANODE pinout and 2.5 V reference core. However, TL1431AID offers tighter 0.25% accuracy and lower ±13 ppm/°C tempco versus standard TL431's 0.5% and ±50 ppm/°C-providing immediate performance uplift without layout changes.

Does TL1431AID require external compensation for stability?

No external compensation is required for TL1431AID when driving capacitive loads ≤10 nF, per Figure 20 in ST's datasheet. For larger capacitors (e.g., >100 nF), a series resistor (typically 10–100 Ω) between REF and the divider node restores phase margin-verified in application note AN2718.

What is the power dissipation limit of TL1431AID in SO-8 package?

In SO-8 "batwing" package, TL1431AID has a maximum power dissipation of 960 mW at T_amb = 25 °C (R_thJA = 85 °C/W), calculated assuming T_j ≤ 150 °C. At +105 °C ambient, derated dissipation drops to ~500 mW-requiring thermal-aware layout with copper pour under exposed pad if operating near 100 mA sink current.

TL1431AID 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:: ±0.25%

Temperature Coefficient:: 100ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 700 µA

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

TL1431AID FAQ

1.How can I place an order for TL1431AID through Aetrix?

Please submit a Request for Quotation (RFQ) for TL1431AID 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 TL1431AID reliable?

The price and inventory of TL1431AID are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431AID is usually 5 days.

3.What payment methods are accepted for TL1431AID?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431AID transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TL1431AID?

TL1431AID orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TL1431AID 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 TL1431AID?

For technical support, including TL1431AID datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431AID requirements.

6.How does Aetrix verify that TL1431AID is sourced from the original manufacturer or authorized distributors?

All TL1431AID 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 TL1431AID meets industry standards.

7.What is the process for return or replacement of TL1431AID?

All TL1431AID units undergo pre-shipment inspection (PSI). If there is an issue with TL1431AID, 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 TL1431AID part is unused and in its original packaging.

Return procedure for TL1431AID:

1.Submit a request within 90 days.

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

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