Diodes Incorporated AZ431LBRTR-E1

Overview

AZ431LBRTR-E1 from Diodes Incorporated is a 1.0% tolerance, low-voltage (1.24 V nominal) adjustable precision shunt regulator in SOT89 package, designed for voltage reference and feedback control in switching power supplies, PC motherboards, and chargers. It delivers 0.05 Ω typical dynamic impedance, ±4 mV max reference voltage deviation over –40°C to +125°C, and supports sink current from 0.1 mA to 100 mA.

For engineers reviewing the AZ431LBRTR-E1 datasheet, AZ431LBRTR-E1 pinout, AZ431LBRTR-E1 application, or AZ431LBRTR-E1 equivalent, this page provides verified electrical parameters, thermal performance data, package-specific layout guidance, and validated alternative options for feedback loop design in industrial and computing power systems.

Technical Context

The AZ431LBRTR-E1 implements a three-terminal bandgap-based shunt reference architecture with internal error amplifier and output stage, enabling precise regulation via external resistor divider. Its sharp turn-on characteristic and low 20 ppm/°C typical temperature coefficient ensure stable reference voltage under varying load and thermal conditions.

It operates as a programmable cathode-controlled current sink: reference input (REF) sets threshold, anode (ANODE) connects to ground or return path, and cathode (CATHODE) sources regulated current into the feedback node. The device remains stable with capacitive loads up to 10 µF without external compensation.

Key Specifications

Pinout & Package

SOT89 package: 3-pin surface-mount, thermally enhanced plastic outline with exposed tab (pin 2 connected to substrate). Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE. Anode must be tied to system ground or return path; cathode connects to feedback node of PWM controller.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDBZR and AS431ASTU-Z, AZ431LBRTR-E1 offers superior thermal handling (770 mW in SOT89), lower dynamic impedance (0.05 Ω), and native 1.24 V reference-making it optimal for high-current, low-voltage, thermally demanding feedback applications where precision and robustness are co-prioritized.

Availability

AZ431LBRTR-E1 is available at Aetrix Electronics and suitable for switching power supplies, PC motherboards, and charger designs requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term manufacturability.

Supply support for AZ431LBRTR-E1 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 AZ431L series belongs to Diodes' precision reference product line, engineered specifically for high-stability, low-drift shunt regulation in cost-sensitive yet thermally demanding power conversion systems.

FAQ

What is the minimum cathode current required for regulation in AZ431LBRTR-E1?

The AZ431LBRTR-E1 requires a minimum cathode current of 55 µA to maintain regulation, as specified in the Electrical Characteristics table under I_K(Min) at T_A = +25°C. This value increases slightly at temperature extremes but remains ≤80 µA across –40°C to +125°C, enabling reliable startup and light-load operation in energy-efficient designs.

Can AZ431LBRTR-E1 replace a standard zener diode in existing designs?

Yes-AZ431LBRTR-E1 can directly replace zener diodes in feedback loops where three-terminal configuration is feasible. Its sharp turn-on, low temperature coefficient (20 ppm/°C), and programmable output (1.24 V–18 V) provide superior accuracy and stability versus discrete zeners, especially under varying load and temperature conditions.

Is the SOT89 package of AZ431LBRTR-E1 thermally optimized for high-current operation?

Yes-the SOT89 package delivers θ_JC = 29.8 °C/W and 770 mW maximum power dissipation, significantly exceeding SOT23/SOT25 alternatives. Its exposed tab enhances heat transfer to PCB copper, making it suitable for applications requiring sustained cathode currents above 50 mA without external heatsinking.

Does AZ431LBRTR-E1 require external compensation for stability?

No-AZ431LBRTR-E1 is internally compensated and remains stable with capacitive loads up to 10 µF, as confirmed in the Performance Characteristics section. This eliminates the need for series damping resistors or RC networks in most switching power supply feedback implementations, simplifying layout and reducing component count.