Diodes Incorporated AZ431AZ-BTRE1

Overview

AZ431AZ-BTRE1 from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 0.4% reference voltage tolerance, 2.5V nominal VREF, and guaranteed thermal stability from –40°C to +125°C. It replaces Zener diodes in feedback loops of switching power supplies, battery chargers, and voltage adapters, delivering low output impedance (0.2Ω typical), sharp turn-on, and stable regulation under capacitive loads up to 10µF.

For engineers reviewing the AZ431AZ-BTRE1 datasheet, AZ431AZ-BTRE1 pinout, AZ431AZ-BTRE1 application, or AZ431AZ-BTRE1 equivalent, key selection criteria include its programmable 2.5–18V output range, ±4.5mV max VREF drift over full temperature range, 1mA–100mA sink current capability, and TO-92 ammo-packaged form factor optimized for cost-sensitive industrial power designs.

Technical Context

The AZ431AZ-BTRE1 implements an internal bandgap reference and high-gain error amplifier driving a NPN pass transistor, enabling precise cathode voltage regulation via external resistor divider. Its functional block diagram confirms direct REF–ANODE–CATHODE topology with no internal compensation-stability relies on external capacitor placement per load conditions.

It operates as a two-quadrant shunt device: sinking current when cathode voltage exceeds (1+R1/R2)×VREF, and entering high-impedance off-state below regulation threshold. Dynamic impedance remains ≤0.5Ω from 1–100mA, and small-signal gain stays >40dB below 10kHz, supporting fast transient response in PWM feedback paths.

Key Specifications

Pinout & Package

AZ431AZ-BTRE1 is supplied in TO-92 package with ammo packing (lead-free, RoHS-compliant). The package features axial leads, plastic body, and substrate-connected pin 2 requiring connection to ANODE or left open per datasheet Note 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR, AZ431AZ-BTRE1 offers tighter 0.4% tolerance and lower thermal drift but lacks high-voltage headroom; versus KA431AZTA, it delivers 2× better VREF accuracy and 3.5× lower ΔVREF over temperature-justifying premium in precision power designs.

Availability

AZ431AZ-BTRE1 is available at Aetrix Electronics and suitable for switching power supply design, battery charger development, and industrial voltage adapter production requiring stable component supply, consistent TO-92 ammo-packaging, and RoHS-compliant manufacturing traceability.

Supply support for AZ431AZ-BTRE1 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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.

AZ431AZ-BTRE1 belongs to Diodes' precision shunt regulator product line, engineered for high-accuracy voltage reference and feedback applications in cost-sensitive, thermally demanding power conversion systems.

FAQ

What is the minimum cathode current required for regulation in AZ431AZ-BTRE1?

The minimum cathode current (IKA(Min)) is 0.4mA at VREF, rising to 1.0mA maximum across –40°C to +125°C. Below this threshold, the device exits regulation and enters high-impedance state-designs must ensure resistor divider bias current exceeds this value under all operating conditions, including light-load and cold-start scenarios.

Can AZ431AZ-BTRE1 replace a standard 5.1V Zener diode directly?

No direct replacement is possible without circuit modification. AZ431AZ-BTRE1 requires a three-resistor divider to set output voltage and draws ~0.7µA reference current, whereas Zeners operate with simple series resistor bias. A direct swap would cause catastrophic regulation failure; redesign of feedback network and biasing is mandatory.

Is pin 2 (ANODE) electrically isolated in the TO-92 package?

No-pin 2 is internally bonded to the die substrate and must be connected to the ANODE potential (typically system ground) or left open per datasheet Note 1. Leaving it floating violates thermal specifications and may cause parameter shift or premature failure due to uncontrolled substrate bias.

Does AZ431AZ-BTRE1 require an external compensation capacitor?

No external compensation capacitor is required for stability. The device is inherently stable with capacitive loads up to 10µF, as verified in Figure 8 of DS41517 Rev. 4–2. Adding series resistance or parallel RC networks degrades performance and is unnecessary unless oscillation is observed in specific PCB layouts with >10µF output capacitance.