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

Diodes Incorporated AP431IARTR-G1

Name: AP431IARTR-G1
Brand: Diodes Incorporated
SKU: AP431IARTR-G1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP431IARTR-G1

Manufacturer:: Diodes Incorporated

Category:: Voltage Reference

Package:: TO-243AA

Datasheet:: AP431IARTR-G1.pdf

Description:: IC VREF SHUNT ADJ 0.5% SOT89-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

AP431IARTR-G1 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with 0.5% initial reference voltage tolerance (2.495 V), low minimum cathode current of 50 µA (typ), and 36 V max cathode voltage. It replaces Zener diodes in feedback loops of switching power supplies, battery chargers, and voltage adapters where thermal stability and low-power operation are critical.

For engineers reviewing the AP431IARTR-G1 datasheet, AP431IARTR-G1 pinout, AP431IARTR-G1 application, or AP431IARTR-G1 equivalent, key selection criteria include its 11 mV reference deviation over –40°C to +125°C, 0.1 Ω dynamic impedance, sink current range of 100 µA–100 mA, and SOT-89 package compatibility with high-reliability industrial power control designs.

Technical Context

The AP431IARTR-G1 implements a bandgap-based 2.495 V reference with internal error amplifier and NPN output stage, enabling precise voltage regulation via external resistor divider. Its low 50 µA minimum cathode current allows stable operation under ultra-low standby loads-critical for energy-efficient AC/DC adapters and USB PD chargers.

It features low temperature coefficient (11 mV typical drift across –40°C to +125°C), high capacitive load stability (no oscillation up to 100 µF), and robust ESD immunity (5.5 kV HBM). The device operates with cathode-to-anode voltage up to 36 V and supports sink currents from 100 µA to 100 mA without external compensation.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage	2.495 V ±0.5% at +25°C - sets precise output voltage threshold in feedback networks
Min Cathode Current	50 µA (typ), 100 µA (max) - enables regulation in micropower standby modes
Dynamic Impedance	0.1 Ω (typ) - ensures minimal output voltage variation under load transients
Ref Voltage Drift	11 mV (typ) over –40°C to +125°C - guarantees stable setpoint across automotive/industrial ambient ranges
Cathode Voltage Range	2.495 V to 36 V - supports wide-output DC-DC converters and programmable references
Sink Current Range	100 µA to 100 mA - accommodates both light-load biasing and high-current error amplification
Package	SOT-89 (RoHS/Green, tape & reel) - surface-mount compatible with high thermal dissipation (80°C/W θ_JC)

Pinout & Package

SOT-89 package with 3-pin configuration: compact, thermally enhanced plastic outline optimized for power regulation applications. Pin 1 = REF (reference input), Pin 2 = ANODE (ground return), Pin 3 = CATHODE (regulated output node).

Pin/Terminal	Circuit Role	Design Meaning
1 (REF)	Reference Input	High-impedance node connected to resistor divider midpoint; sets regulation point via V_REF × (1 + R1/R2)
2 (ANODE)	Ground Reference	Common return path for cathode current and reference bias; must be low-impedance to avoid regulation error
3 (CATHODE)	Regulated Output Node	Sinks adjustable current to maintain V_OUT; connects to primary-side optocoupler LED or error amplifier input in isolated SMPS

Key Features

Feature	Design Value
Low Minimum Cathode Current	50 µA typ - reduces quiescent power loss in no-load or burst-mode operation
Precision Reference Tolerance	±0.5% at +25°C - eliminates need for post-production trimming in cost-sensitive power supplies
Wide Temperature Stability	11 mV drift over –40°C to +125°C - maintains accuracy in under-hood or industrial enclosure environments
Capacitive Load Immunity	No oscillation up to 100 µF - simplifies layout in noisy switcher feedback paths without added compensation
Green Packaging	RoHS-compliant, halogen- and antimony-free - meets IEC 61249-2-21 and JEDEC JS709C requirements

Applications

AC/DC Adapter Feedback

USB-C Charger Regulation

Use Scenario: Primary-side feedback in 5–65 W offline flyback converters powering wall adapters.

IC Role / Device Role / Timing Role: Adjustable shunt regulator providing precise voltage reference to optocoupler LED, closing secondary-side regulation loop.

Use Value: 50 µA min cathode current enables <100 mW no-load consumption; 0.1 Ω dynamic impedance suppresses ripple-induced output variation.

Use Scenario: Programmable voltage reference in multi-protocol USB PD 3.0 chargers supporting 5–20 V output profiles.

IC Role / Device Role / Timing Role: Precision shunt element in DAC-controlled feedback network, setting V_OUT via resistor ladder and MCU-adjusted divider ratio.

Use Value: 2.495 V ±0.5% reference ensures ±30 mV absolute output accuracy across full 20 V range; thermal stability prevents derating at elevated PCB temperatures.

Industrial SMPS Monitoring

Graphic Card VRM Reference

Use Scenario: Overvoltage protection and rail monitoring in 24 V/48 V industrial DC-DC modules with remote sense capability.

IC Role / Device Role / Timing Role: High-accuracy shunt comparator detecting >105% nominal rail voltage and triggering shutdown logic via open-collector interface.

Use Value: 36 V cathode rating supports direct connection to 48 V bus; 11 mV temp drift avoids false trips across –40°C to +85°C operating envelope.

Use Scenario: Secondary-side voltage reference for GPU core VRMs requiring tight transient response and <±1% output tolerance.

IC Role / Device Role / Timing Role: Low-impedance reference source for multiphase controller error amplifiers, improving load-step accuracy and reducing output capacitor count.

Use Value: 0.1 Ω dynamic impedance minimizes gain error during 10 A/µs load steps; SOT-89 thermal resistance (80°C/W) sustains 100 mA sink without derating.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TL431ACDR	2.495 V ±1%, 100 µA min cathode current, SOIC-8 package	Higher min cathode current increases no-load power; larger footprint limits high-density layouts	Preferred when legacy SOIC-8 board space exists and 1% tolerance is acceptable
AS431ATR-E1	2.500 V ±0.5%, 60 µA min cathode current, SOT-23 package	SOT-23 has higher thermal resistance (140°C/W); lower max cathode voltage (24 V)	Selected for space-constrained designs where 24 V max and 60 µA min current suffice

Compared with TL431ACDR and AS431ATR-E1, the AP431IARTR-G1 delivers tighter initial tolerance (0.5%), lowest min cathode current (50 µA), and highest cathode voltage rating (36 V) in an industry-standard SOT-89 package-making it optimal for high-efficiency, wide-input industrial and adapter applications demanding thermal robustness and micropower regulation.

Availability

AP431IARTR-G1 is available at Aetrix Electronics and suitable for switching power supplies, battery chargers, and industrial voltage adapters requiring stable component supply, RoHS/Green compliance, and long-term lifecycle support.

Supply support for AP431IARTR-G1 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP431i series belongs to Diodes' precision shunt regulator product line, engineered specifically for high-stability, low-quiescent-power feedback control in AC/DC and DC/DC converters-addressing efficiency, thermal reliability, and design simplicity in power supply systems.

FAQ

What is the maximum cathode voltage rating for AP431IARTR-G1?

The AP431IARTR-G1 supports a maximum cathode-to-anode voltage of 36 V under recommended operating conditions, with an absolute maximum rating of 40 V. This allows direct use in 24 V and 36 V industrial bus applications without external clamping, provided power dissipation remains within the SOT-89 package limit of 750 mW.

How does the 50 µA minimum cathode current impact system efficiency?

The 50 µA typical minimum cathode current enables stable regulation at ultra-low load levels, reducing no-load power consumption in standby mode. In a 12 V adapter with 100 kΩ upper feedback resistor, this allows regulation down to ~120 µW total quiescent loss-critical for meeting DOE Level VI and EU CoC Tier 2 efficiency standards.

Can AP431IARTR-G1 replace TL431 in existing designs?

Yes, AP431IARTR-G1 is pin-compatible with TL431 in SOT-89 footprint and shares identical pinout (REF-ANODE-CATHODE), but offers superior specs: 0.5% vs. 1% reference tolerance, 50 µA vs. 100 µA min cathode current, and better thermal resistance. No circuit changes are needed, though layout should verify thermal relief for 750 mW dissipation.

Is AP431IARTR-G1 suitable for automotive under-hood applications?

Yes-the device is rated for –40°C to +125°C ambient operation, with only 11 mV reference voltage drift across that range and guaranteed stability under capacitive loads up to 100 µF. Its SOT-89 package provides adequate thermal performance for under-hood power modules, provided PCB copper area meets Diodes' recommended pad layout (4.6 mm × 1.55 mm thermal pad).

AP431IARTR-G1 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Package/Case:: TO-243AA

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Reference Type:: Shunt

Output Type:: Adjustable

Voltage - Output (Min/Fixed):: 2.5V

Voltage - Output (Max):: 36 V

Current - Output:: 100 mA

Tolerance:: ±0.5%

Temperature Coefficient:: -

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: -

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 100 µA

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89-3

AP431IARTR-G1 FAQ

1.How can I place an order for AP431IARTR-G1 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP431IARTR-G1 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 AP431IARTR-G1 reliable?

The price and inventory of AP431IARTR-G1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP431IARTR-G1 is usually 5 days.

3.What payment methods are accepted for AP431IARTR-G1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP431IARTR-G1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP431IARTR-G1?

AP431IARTR-G1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP431IARTR-G1 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 AP431IARTR-G1?

For technical support, including AP431IARTR-G1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP431IARTR-G1 requirements.

6.How does Aetrix verify that AP431IARTR-G1 is sourced from the original manufacturer or authorized distributors?

All AP431IARTR-G1 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 AP431IARTR-G1 meets industry standards.

7.What is the process for return or replacement of AP431IARTR-G1?

All AP431IARTR-G1 units undergo pre-shipment inspection (PSI). If there is an issue with AP431IARTR-G1, 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 AP431IARTR-G1 part is unused and in its original packaging.

Return procedure for AP431IARTR-G1:

1.Submit a request within 90 days.

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

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