Diodes Incorporated AP431IAZTR-G1

Overview

AP431IAZTR-G1 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with 0.5% initial reference voltage tolerance (2.500 V at +25°C), 50 µA typical minimum cathode current for regulation, and operation up to 36 V cathode voltage. It replaces Zener diodes in feedback loops of switching power supplies, battery chargers, and voltage adapters where low-power, high-stability regulation is required.

For engineers reviewing the AP431IAZTR-G1 datasheet, AP431IAZTR-G1 pinout, AP431IAZTR-G1 application, or AP431IAZTR-G1 equivalent, key selection criteria include its low 50 µA regulation threshold, ±11 mV reference deviation over –40°C to +125°C, 0.1 Ω dynamic impedance, and TO-92 package compatibility with legacy designs requiring through-hole mounting and thermal robustness.

Technical Context

The AP431IAZTR-G1 implements a bandgap-referenced error amplifier driving an NPN output stage, enabling precise voltage regulation via external resistor dividers. Its sharp turn-on characteristic and low temperature coefficient (±11 mV over full range) ensure stable feedback across industrial temperature extremes.

It operates as a 2.5 V reference sink with programmable output from 2.5 V to 36 V, supporting both shunt regulation and current-source configurations. The device maintains stability under capacitive loads up to 100 µF and exhibits <0.3 µA reference current drift over temperature.

Key Specifications

Pinout & Package

AP431IAZTR-G1 is housed in a TO-92 package (3-lead through-hole), with leads arranged in linear order: Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE (top view, flat side facing viewer). This configuration matches industry-standard 431 pinouts for drop-in replacement in legacy designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AP431SARTR-G1, AP431IAZTR-G1 uniquely delivers 0.5% accuracy *and* 50 µA regulation threshold in a through-hole TO-92 package-enabling both precision and ultra-low-power operation where alternatives require trade-offs in tolerance, current, or mounting method.

Availability

AP431IAZTR-G1 is available at Aetrix Electronics and suitable for AC-DC adapters, laptop chargers, and industrial switching power supplies requiring stable component supply with long-term manufacturability and RoHS/Green compliance.

Supply support for AP431IAZTR-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 high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP431i series was designed specifically to replace Zener diodes in feedback networks of isolated power converters, emphasizing low minimum cathode current, wide temperature stability, and drop-in compatibility with legacy 431 footprints.

FAQ

What is the maximum cathode voltage rating for AP431IAZTR-G1?

The absolute maximum cathode-to-anode voltage is 40 V, but the recommended operating limit is 36 V. Exceeding 36 V risks violating the device's safe operating area and may cause premature degradation of the internal bandgap reference, especially at elevated temperatures above +85°C.

Can AP431IAZTR-G1 drive an optocoupler LED directly?

Yes-it sinks up to 100 mA, sufficient to drive common PC817 or SFH615A optocouplers at 5–10 mA forward current. Its 0.1 Ω dynamic impedance ensures minimal voltage droop during transient loading, maintaining stable feedback loop gain in isolated SMPS designs.

How does the 0.5% reference tolerance affect output voltage accuracy?

With a standard two-resistor divider, the 0.5% V_REF tolerance contributes directly to total output error. For a 12 V output (R1/R2 = 3.8), the reference error alone accounts for ±60 mV; combined with resistor tolerances, total accuracy remains within ±1.5% without trimming.

Is AP431IAZTR-G1 compatible with lead-free solder reflow profiles?

Yes-the TO-92 package is rated for peak reflow temperatures up to 260°C per JEDEC J-STD-020, and the device is fully RoHS-compliant with no lead, halogens, or antimony. Standard Pb-free SAC305 profiles (peak 245°C, 60 sec above 220°C) are supported without derating.