Diodes Incorporated AP432AQL-7

Overview

AP432AQL-7 from Diodes Incorporated is a 3-terminal adjustable precision shunt regulator with ±0.5% reference voltage tolerance, 1.24 V nominal V_REF, and guaranteed stability over –20°C to +85°C. It sinks up to 200 mA, features 0.2 Ω dynamic output impedance, and sets programmable output voltages from 1.24 V to 20 V using two external resistors - widely used in feedback loops of isolated DC-DC converters and voltage monitors.

For engineers reviewing the AP432AQL-7 datasheet, AP432AQL-7 pinout, AP432AQL-7 application, or AP432AQL-7 equivalent, key selection criteria include reference accuracy, cathode current capability, temperature coefficient (30 ppm/°C), low noise, and SOT25 package compatibility with space-constrained power supply designs.

Technical Context

The AP432A operates as a precision two-terminal shunt reference with an internal bandgap-derived 1.24 V reference and high-gain error amplifier driving an NPN output stage. Its active sink topology enables sharp turn-on response and stable regulation even under light-load conditions (I_K(A-MIN) = 150 µA).

Designed for closed-loop feedback in flyback, forward, and offline AC-DC converters, it replaces Zener diodes by delivering superior initial accuracy, lower temperature drift, and programmable setpoints without trimming. The device's low dynamic impedance (0.2 Ω typ.) ensures minimal output voltage deviation across load transients.

Key Specifications

Pinout & Package

AP432AQL-7 is housed in a RoHS-compliant, lead-free SOT25 (SC-74A) surface-mount package measuring 2.80 mm × 2.90 mm × 1.10 mm (L × W × H), optimized for automated assembly and thermal dissipation in compact power stages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AZ431L and TL431BIDBZR, AP432AQL-7 delivers higher sink current (200 mA vs. ≤100 mA), lower dynamic impedance (0.2 Ω vs. ≥0.5 Ω), and SOT25 packaging with dedicated NC pins for noise isolation - making it optimal for mid-to-high-power isolated SMPS feedback where regulation fidelity and layout robustness are prioritized.

Availability

AP432AQL-7 is available at Aetrix Electronics and suitable for AC-DC adapters, isolated flyback converters, overvoltage protection circuits, and programmable current limiters requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for AP432AQL-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 high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP432/A series belongs to Diodes' precision reference product line, engineered specifically for high-accuracy, low-drift voltage regulation in isolated power supply feedback loops and programmable analog control circuits.

FAQ

What is the maximum cathode voltage rating for AP432AQL-7?

The absolute maximum cathode voltage (V_CV) is 20 V. Exceeding this risks permanent damage. In practice, the device regulates only when cathode voltage exceeds the programmed output (≥1.24 V); operation above 20 V violates safe operating area limits and must be prevented by upstream clamping or zener limiting.

Can AP432AQL-7 replace a standard Zener diode directly?

Yes - with proper external resistor configuration. Unlike passive Zeners, AP432AQL-7 requires a three-terminal connection (cathode, anode, REF) and draws ~1.4–3.5 µA reference current. It offers superior accuracy (±0.5%), lower impedance (0.2 Ω), and sharper knee characteristics, but demands correct biasing and stability compensation per the datasheet's CL vs. I_KA curves.

Why does AP432AQL-7 have two NC pins in the SOT25 package?

The two NC pins (pins 4 and 5) are electrically unconnected die bond pads reserved for process or test flexibility. They improve mechanical stability during reflow and reduce package warpage. Diodes Incorporated recommends leaving them floating; grounding is acceptable if needed for EMI shielding, but no current should be sourced/sunk through them.

Is AP432AQL-7 suitable for automotive applications?

No - its specified operating temperature range is –20°C to +85°C, which falls short of AEC-Q100 Grade 2 (–40°C to +105°C) or Grade 1 requirements. While functional in cabin-located non-safety systems, it lacks automotive qualification, stress testing, and PPAP documentation; use AZ431L-A or TL431-Q1 for qualified automotive designs.