Diodes Incorporated AH287-PG-B

Overview

AH287-PG-B from Diodes Incorporated is a high-voltage Hall-effect smart fan motor controller integrating an on-chip Hall sensor, dual complementary open-drain drivers, rotor-lock shutdown detection, automatic restart logic, and built-in Zener protection. It operates from 3.8V to 28V, delivers 400mA average output current, and is packaged in lead-free SIP-4L for brushless DC fan control in automotive HVAC and industrial cooling systems.

For engineers reviewing the AH287-PG-B datasheet, AH287-PG-B pinout, AH287-PG-B application, or AH287-PG-B equivalent, key selection considerations include its integrated Hall sensing, lock-detection timing (0.46s ON / 2.76s OFF), output saturation voltage (≤700mV at 300mA), thermal derating curves, and SIP-4L package compatibility with standard fan PCB layouts.

Technical Context

The AH287-PG-B implements a monolithic Hall-based commutation controller with internal regulator, lock-detection comparator, and recovery timer circuitry. Its dual open-drain outputs (DO and DOB) drive external N-channel MOSFETs in a half-bridge configuration, while the on-chip Hall plate senses rotor position without external sensors.

Lock protection activates when no magnetic transition is detected for ≥0.46s, disabling both outputs; automatic restart occurs after ≥2.76s of continuous stall. The device features built-in Zener clamping (42–65V breakdown) on outputs and operates across –40°C to +100°C ambient temperature.

Key Specifications

Pinout & Package

Package: SIP-4L (Single In-line Package, 4-pin, lead-free, green molding compound). Pin 1 = Vdd, Pin 2 = DO, Pin 3 = DOB, Pin 4 = GND. No NC pins; all terminals electrically active.

Key Features

Applications

Availability

AH287-PG-B is available at Aetrix Electronics and suitable for automotive HVAC blowers, industrial cabinet cooling fans, server rack exhaust systems, and medical diagnostic equipment cooling requiring stable component supply and legacy design continuity.

Supply support for AH287-PG-B 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 precision timing solutions for industrial, automotive, and computing markets.

The AH287 belongs to Diodes' smart motor driver product line, designed specifically for cost-optimized, sensor-integrated BLDC fan control in thermally demanding environments without microcontroller dependency.

FAQ

What is the function of the DOB pin?

DOB is the complementary open-drain output terminal used with DO to generate phase-shifted drive signals for two-phase commutation of brushless DC fans. It shares identical timing, protection logic, and current capability (400mA avg) with DO, enabling full H-bridge control using external N-channel MOSFETs.

Can AH287-PG-B operate at 30V supply?

No - the absolute maximum supply voltage is 30V, but recommended operating voltage is limited to 28V. Operation above 26.4V risks exceeding current limits due to reduced coil efficiency, as explicitly noted in the datasheet's Recommended Operating Conditions section.

Is AH287-PG-B pin-compatible with AH287-PL-B?

Yes - both variants use the identical SIP-4L package and share identical pinout (Vdd, DO, DOB, GND). The suffix difference (-PG-B vs. -PL-B) denotes green molding compound versus standard lead-free compound; electrical and thermal performance are equivalent.

Does AH287-PG-B require an external capacitor on Vdd?

Yes - a minimum 10µF electrolytic capacitor (e.g., 25V-rated) is required between Vdd and GND to stabilize the internal regulator and suppress voltage spikes during motor commutation. The datasheet recommends an E-cap for optimal performance and reliability.