Diodes Incorporated AP431RL-7

Overview

AP431RL-7 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. It operates from −20°C to +85°C and sets output voltages from 2.495V to 36V using two external resistors-commonly deployed in feedback loops of isolated DC-DC converters and voltage monitors.

For engineers reviewing the AP431RL-7 datasheet, AP431RL-7 pinout, AP431RL-7 application, or AP431RL-7 equivalent, key selection criteria include reference voltage tolerance, cathode current range, temperature coefficient (30ppm/°C), minimum regulation current (300μA), and SC59R package thermal performance for space-constrained power supplies.

Technical Context

The AP431RL-7 implements an internal bandgap reference and high-gain transconductance amplifier driving an NPN output stage, enabling sharp turn-on and low-output-impedance regulation. Its active output circuitry delivers fast response to load transients while maintaining stable operation across input voltage variations from 2.5V to 36V.

It functions as a programmable voltage-controlled current sink: cathode current varies linearly with error between REF pin voltage and internal 2.495V reference, supporting precise closed-loop control in flyback feedback networks, overvoltage protection circuits, and constant-current LED drivers.

Key Specifications

Pinout & Package

AP431RL-7 is packaged in SC59R - a 3-pin, lead-free, RoHS-compliant surface-mount package with 1.6mm × 2.8mm footprint and 0.95mm height, optimized for thermal dissipation in compact power supplies.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431BIDBZR and AS431ARTDT-13, AP431RL-7 offers optimal balance of SC59R compactness, 250mA sink capability, and 0.2Ω impedance-making it preferred for space-constrained, medium-power flyback feedback where ±1% accuracy suffices.

Availability

AP431RL-7 is available at Aetrix Electronics and suitable for isolated DC-DC converters, voltage monitoring systems, constant-current LED drivers, and crowbar protection circuits requiring stable component supply across production lifecycles.

Supply support for AP431RL-7 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 AP431/AP431A product line targets cost-sensitive, high-volume power regulation applications-designed specifically to replace Zener diodes with superior accuracy, temperature stability, and programmability in feedback and protection circuits.

FAQ

What is the minimum cathode current required for regulation in AP431RL-7?

The AP431RL-7 requires a minimum cathode current of 300μA to maintain regulation, verified per DS31002 Rev. 21–2 electrical characteristics table. This low threshold enables stable operation in ultra-low-power standby modes of AC-DC adapters and IoT power supplies where quiescent current must remain below 1mA.

Can AP431RL-7 be used in place of TL431 in existing designs?

Yes, AP431RL-7 is functionally compatible with TL431 in SC59R footprint designs, sharing identical pinout (Cathode–REF–Anode), 2.495V reference, and shunt regulator topology. However, its 0.2Ω output impedance and 30ppm/°C tempco differ slightly-design validation is required for high-precision applications exceeding ±1% output tolerance.

Does AP431RL-7 support operation above 36V cathode-anode voltage?

No. The absolute maximum cathode voltage is +36V per DS31002 Rev. 21–2 Absolute Maximum Ratings. Exceeding this risks permanent device failure. For >36V applications, external clamping (e.g., series Zener or TVS) is mandatory before the cathode terminal.

What is the thermal resistance (θ_JA) of the SC59R package for AP431RL-7?

While Diodes Incorporated does not publish θ_JA for AP431RL-7 in DS31002, the SC59R package's 400mW power dissipation rating at +25°C ambient implies a typical θ_JA of ~250°C/W under standard JEDEC 2-layer board conditions. Actual thermal performance depends on copper area, via count, and airflow-designers should verify junction temperature using measured power and board-specific thermal modeling.