Diodes Incorporated AP431G-13

Overview

AP431G-13 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with 2.495V ±1% reference voltage, 0.2Ω dynamic output impedance, and 200mA sink current capability, used as a programmable voltage reference or error amplifier in feedback loops of DC-DC converters, linear regulators, and voltage monitors.

For engineers reviewing the AP431G-13 datasheet, AP431G-13 pinout, AP431G-13 application, or AP431G-13 equivalent, this device serves as a Zener diode replacement requiring external resistor programming for output voltages from 2.495V to 36V, with sharp turn-on response and low temperature drift (30ppm/°C) across –20°C to +85°C.

Technical Context

The AP431G-13 implements an internal bandgap reference and high-gain transconductance amplifier driving an NPN pass transistor, enabling precise regulation via external resistive divider at the REF pin. Its active output stage delivers fast turn-on and low dynamic impedance independent of cathode current within 0.1–15mA range.

It operates as a two-quadrant device: sinking current when cathode-to-anode voltage exceeds the programmed threshold, and drawing only 0.19–0.50mA minimum cathode current for regulation. The reference input current remains stable at 1.4–3.5µA with <1.2µA variation over temperature.

Key Specifications

Pinout & Package

AP431G-13 is packaged in SO-8, a surface-mount 8-pin small-outline integrated circuit with exposed thermal pad. Pin 1 is Cathode, Pin 2 is Anode, Pin 4 is REF, and Pins 3, 5–8 are No Connect (NC). This configuration isolates reference sensing from power path while supporting PCB-level thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDR and KA431AZTA, AP431G-13 offers higher sink current (200mA vs. ≤100mA), tighter thermal stability (30ppm/°C vs. 50–92ppm/°C), and SO-8 thermal performance suitable for sustained 1W dissipation-making it preferable for industrial power supplies demanding long-term regulation integrity.

Availability

AP431G-13 is available at Aetrix Electronics and suitable for AC-DC adapters, isolated DC-DC converters, and voltage-monitoring circuits requiring stable component supply with full industrial temperature support and RoHS-compliant packaging.

Supply support for AP431G-13 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 devices, with design centers in Asia, Europe, and the U.S., and manufacturing in China, Malaysia, Taiwan, and the Philippines.

The AP431 series belongs to Diodes' precision analog portfolio, engineered for high-accuracy voltage regulation in power management systems where Zener replacement, low drift, and programmability are critical.

FAQ

What is the maximum cathode voltage the AP431G-13 can regulate?

The AP431G-13 supports cathode-to-anode voltages up to +36V absolute maximum. Its regulation range extends from 2.495V to 36V when configured with appropriate external resistors. Exceeding 36V risks permanent damage, and operation above 30V requires attention to power dissipation limits in the SO-8 package (600mW at +25°C ambient).

Can AP431G-13 replace a standard Zener diode directly?

Yes-AP431G-13 functions as a 3-terminal Zener replacement with superior characteristics: sharper knee, lower dynamic impedance (0.2Ω vs. typical 5–20Ω for Zeners), and guaranteed ±1% reference tolerance. It requires only two external resistors for voltage setting and draws negligible reference current (1.4–3.5µA), eliminating Zener leakage and drift issues.

Does AP431G-13 require a minimum load current to maintain regulation?

Yes-the AP431G-13 requires a minimum cathode current of 0.19mA (typical) to sustain regulation. Below this threshold, the device exits regulation mode and behaves as an open circuit. Designers must ensure the external resistor network or downstream load provides sufficient current under all operating conditions, including light-load or standby states.

How does the SO-8 package of AP431G-13 improve thermal performance over SOT-23 variants?

The SO-8 package provides 600mW power dissipation at +25°C ambient-nearly 50% higher than SOT-23's 400mW rating-due to larger copper area and thermal pad capability. Its 8-pin layout also separates REF and Cathode pins to reduce noise coupling, and the exposed pad option (not used in G-13 variant) enables direct PCB thermal vias for enhanced heat transfer in high-power feedback applications.