Diodes Incorporated AH5773-MP-13

Overview

AH5773 from Diodes Incorporated is a single-chip BLDC motor driver IC with integrated Hall-effect latch sensor, full-bridge H-bridge (RON_TOTAL ≤ 1.9 Ω at 12V/500mA), soft-switching commutation, and tachometer (FG) output. It drives single-coil fans/motors in 2.4–18V systems, supports PWM or voltage-based speed control, and delivers rotor lock protection with automatic restart - used in notebook cooling fans and instrument cooling systems.

For engineers reviewing the AH5773 datasheet, AH5773 pinout, AH5773 application, or AH5773 equivalent, key selection criteria include its dual-package availability (U-DFN2020-6 and MSOP-8EP), standby current <100 µA, overvoltage shutdown threshold (19–23 V), thermal shutdown at +170°C, and FG output compatibility with external speed monitoring circuits.

Technical Context

The AH5773 implements a closed-loop commutation architecture using an on-chip Hall-effect sensor to detect magnetic pole transitions and drive complementary O1/O2 outputs via a low-RDSON full-bridge. Its soft-switching control (tSW = 200 µs typ.) reduces EMI and audible noise during coil current reversal.

Functional blocks include dynamic offset cancellation for Hall sensor stability, temperature- and voltage-compensated references, lock-detect logic with 420 ms tON timeout, and a frequency generator (FG) tied directly to magnetic change events - not motor RPM - requiring external scaling for true tachometry.

Key Specifications

Pinout & Package

Available in two thermally enhanced packages: U-DFN2020-6 (2.0 mm × 2.0 mm, 0.65 mm height) and MSOP-8EP (3.0 mm × 3.0 mm, exposed thermal pad). Both feature exposed pads for PCB-level heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-phase BLDC motor driver applications.

Compared with A4964 and NCV7707, the AH5773 uniquely integrates Hall sensing, soft switching, FG output, and sub-100 µA standby in a 2 mm × 2 mm DFN - making it optimal for cost-sensitive, low-noise, low-profile cooling applications where full integration reduces validation effort and time-to-market.

Availability

AH5773 is available at Aetrix Electronics and suitable for desktop CPU cooling fans, notebook internal fans, and industrial instrument cooling systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for AH5773 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 solutions for power management, signal integrity, and connectivity applications.

The AH5773 belongs to Diodes' motor driver product line, designed specifically for compact, low-noise, single-phase BLDC fan control in computing, industrial, and medical equipment - emphasizing integration, protection, and ease of use.

FAQ

What is the function of the FG pin, and how is it used in system design?

The FG (Frequency Generator) pin is an open-drain output that pulses on each magnetic polarity transition detected by the internal Hall sensor - not per motor revolution. To derive true RPM, external circuitry must divide the FG frequency by the number of magnet poles. A 10 kΩ pull-up resistor to VDD is required; FG leakage current is ≤1 µA, ensuring compatibility with low-power microcontrollers.

How does rotor lock protection work, and what happens after detection?

Rotor lock is detected when no magnetic transitions occur for 420 ms (tON), triggering immediate shutdown of O1/O2 outputs. The device enters standby mode (<100 µA) and clears the lock flag. Upon restoration of magnetic activity, it automatically restarts commutation within 100 µs - no external reset or PWM reassertion needed - enabling hands-free recovery in blocked-fan scenarios.

Can the AH5773 drive motors outside the 2.4–18 V range, and what limits apply?

The absolute maximum VDD is 24 V (transient only), but functional operation is guaranteed only from 2.4 V to 18 V. Below 2.4 V, Hall sensitivity degrades and startup torque drops; above 18 V, overvoltage shutdown activates at 19–23 V. Sustained operation beyond 18 V risks premature shutdown or reduced reliability - no derating curve supports continuous >18 V use.

What thermal considerations apply when using the U-DFN2020-6 package?

In U-DFN2020-6, power dissipation is thermally limited to 1230 mW at 25°C with two thermal vias to inner copper layers. At 85°C ambient, derated capacity falls to ~640 mW. PCB layout must include the exposed pad soldered to ≥1 cm² copper pour with ≥2 thermal vias (0.3 mm diameter) - insufficient copper area or missing vias cause junction temperatures to exceed +170°C under 500 mA load.