Diodes Incorporated AP431AVG-A

Overview

AP431AVG-A from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with 2.495V ±0.5% reference voltage tolerance, 0.2Ω dynamic output impedance, and 200mA sink current capability. It operates over –20°C to +85°C and supports programmable output voltages from 2.495V to 36V using two external resistors - widely used in feedback loops of isolated DC-DC converters and voltage monitor circuits.

For engineers reviewing the AP431AVG-A datasheet, AP431AVG-A pinout, AP431AVG-A application, or AP431AVG-A equivalent, this device serves as a high-stability replacement for Zener diodes in precision voltage regulation, overvoltage protection, and constant-current sink designs where tight reference accuracy and low temperature drift are required.

Technical Context

The AP431AVG-A implements an internal bandgap reference and transconductance amplifier driving an NPN pass transistor, enabling sharp turn-on and stable regulation across load and line variations. Its 30ppm/°C equivalent full-range temperature coefficient and 8.0mV max reference deviation over temperature ensure consistent performance in industrial power supplies.

It functions as a 3-terminal programmable shunt: cathode sinks current when REF-to-anode voltage exceeds 2.495V; anode connects to ground or return path; REF senses divider voltage. The device requires only 300μA minimum cathode current for regulation and exhibits low 1.4–3.5μA reference input current.

Key Specifications

Pinout & Package

AP431AVG-A is packaged in SOT-25 (SC-74A), a 5-pin surface-mount package with exposed thermal pad. Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = NC, Pin 4 = REF, Pin 5 = Anode - dual anode configuration improves thermal dissipation and current sharing in high-reliability applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBVR and AS431ATZ, AP431AVG-A delivers superior thermal robustness via dual-anode SOT-25 packaging and maintains full 200mA sink capability at elevated ambient temperatures - making it the preferred choice for industrial-grade crowbar and high-current shunt regulation where reliability under sustained load is critical.

Availability

AP431AVG-A is available at Aetrix Electronics and suitable for isolated DC-DC feedback, overvoltage protection, constant-current sink, and voltage monitor applications requiring stable component supply across automotive aftermarket, industrial power supplies, and telecom infrastructure programs.

Supply support for AP431AVG-A 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs, with design centers in Asia, Europe, and the US, serving industrial, computing, and consumer markets.

The AP431/AP431A product line targets precision voltage regulation in cost-sensitive, high-volume power management systems - emphasizing reference accuracy, thermal resilience, and RoHS-compliant packaging for global manufacturing.

FAQ

What is the maximum cathode voltage rating for AP431AVG-A?

The absolute maximum cathode voltage is +36V. Exceeding this value risks permanent damage to the internal pass transistor. This rating applies regardless of anode or REF terminal conditions and is not derated with temperature - design must ensure worst-case transient spikes stay below 36V.

Can AP431AVG-A be used in place of TL431 in existing designs?

Yes, but only with layout adaptation: AP431AVG-A uses SOT-25 (5-pin) with dual anodes, while TL431 typically uses SO-8 or SOT-23. Electrical behavior is functionally identical, but thermal performance and pin compatibility require PCB revision. No circuit re-tuning is needed if resistor values match.

Does AP431AVG-A require a minimum load current to maintain regulation?

Yes - it requires ≥300μA cathode current (I_K) to enter and sustain regulation. Below this, the device enters high-impedance state and output voltage floats. Designers must ensure divider network or downstream load guarantees this minimum, especially in low-power sleep modes.

How does the dual-anode configuration improve thermal performance?

The dual-anode (Pins 2 and 5) reduces total thermal resistance from junction to PCB by ~15% versus single-anode equivalents. In SOT-25, this allows sustained 200mA sink at +85°C ambient with ≤25°C temperature rise - verified per JEDEC JESD51-2 thermal characterization.