Diodes Incorporated AP432QL-7

Overview

AP432QL-7 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with ±1% reference voltage tolerance (1.24 V), 200 mA sink current capability, and 0.2 Ω dynamic output impedance. It operates over –20°C to +85°C and sets programmable output voltages from 1.24 V to 20 V using two external resistors - widely deployed in feedback loops of isolated DC-DC converters and voltage monitors.

For engineers reviewing the AP432QL-7 datasheet, AP432QL-7 pinout, AP432QL-7 application, or AP432QL-7 equivalent, key selection criteria include cathode current regulation threshold (150 µA), temperature coefficient (30 ppm/°C), low-noise reference stability, and SOT25 package compatibility with space-constrained power supply designs.

Technical Context

The AP432QL-7 implements an internal bandgap reference amplifier driving an active NPN output stage, enabling sharp turn-on response and stable regulation under varying load and line conditions. Its functional block diagram shows direct reference (REF), anode (A), and cathode (C) terminals with no internal compensation - requiring external RC networks for stability per application circuit requirements.

It delivers precise voltage regulation by comparing a divided sample of cathode voltage against its 1.24 V reference; error amplification drives the cathode current to maintain V_KA = V_REF(1 + R₁/R₂). Dynamic output impedance remains ≤0.5 Ω up to 15 mA AC signal swing at frequencies ≤1 kHz.

Key Specifications

Pinout & Package

AP432QL-7 is packaged in SOT25 - a 5-pin surface-mount package with exposed thermal pad, RoHS-compliant lead-free finish, and 550 mW power dissipation rating at +25°C ambient. Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = REF, Pin 4 = NC, Pin 5 = NC (top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AZ431L and TL431BIDBZR, AP432QL-7 offers superior sink current (200 mA vs. ≤100 mA) and lower dynamic impedance (0.2 Ω vs. ≥0.35 Ω), making it optimal for compact, high-transient-response shunt regulation in SOT25-space-constrained designs.

Availability

AP432QL-7 is available at Aetrix Electronics and suitable for industrial power adapters, LED drivers, and isolated DC-DC converters requiring stable component supply with consistent parametric performance across manufacturing lots.

Supply support for AP432QL-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The AP432 series belongs to Diodes' precision reference product line, engineered specifically for high-accuracy, low-drift shunt regulation in cost-sensitive power management applications - emphasizing manufacturability, thermal robustness, and RoHS/Green compliance.

FAQ

What is the minimum cathode current required for regulation in AP432QL-7?

The AP432QL-7 requires a minimum cathode current of 150 µA to maintain regulation, verified across –20°C to +85°C. This low threshold enables stable operation in standby or light-load conditions, such as in energy-efficient AC-DC adapters meeting Level VI efficiency standards.

Can AP432QL-7 replace a Zener diode directly in existing designs?

Yes - AP432QL-7 can directly replace Zener diodes in most shunt regulation roles, provided the external resistor divider is recalculated for 1.24 V reference and the cathode current remains within 150 µA–200 mA. Its active output stage provides sharper knee characteristics and lower dynamic impedance than passive Zeners.

Does AP432QL-7 require external compensation for stability?

Yes - stability depends on external capacitor (C_L) and load conditions. The datasheet defines stability boundaries (e.g., 0.001–100 µF C_L at 10 mA I_KA); layout must follow recommended pad dimensions and minimize parasitic inductance on cathode and REF traces.

What is the maximum allowable cathode-to-anode voltage for AP432QL-7?

The absolute maximum cathode voltage is 20 V relative to anode. Exceeding this risks permanent damage. In practice, designs should limit V_KA to ≤18 V with appropriate derating margin, especially at elevated temperatures where power dissipation and junction temperature must remain below 150°C.