Diodes Incorporated AH291-YL-13

Overview

AH291-YL-13 from Diodes Incorporated is a monolithic low-voltage Hall-effect smart fan motor controller integrating on-chip Hall sensor, dual complementary open-collector drivers (DO/DOB), rotor-lock detection, automatic restart, and built-in Zener output protection. It operates from 1.8V to 5.75V, delivers 400mA average output current, and supports SIP-4L and SOT89-5L packages for compact BLDC cooling fan designs.

For engineers reviewing the AH291-YL-13 datasheet, AH291-YL-13 pinout, AH291-YL-13 application, or AH291-YL-13 equivalent, this device serves as a self-protected, hall-sensored commutation controller for two-coil brushless DC fans in space-constrained thermal management systems where lock-detection reliability and low-voltage startup are critical.

Technical Context

The AH291 implements integrated Hall sensing with magnetic operate/release points of 30–60 G (Bop) and –60 to –30 G (Brp), enabling precise rotor position detection. Its control logic includes dedicated lock-detect circuitry that triggers shutdown after 0.4s (TRLP-ON) and initiates periodic 2.4–3.6s recovery cycles (TRLP-OFF) until mechanical obstruction clears.

Each output driver features 1.75Ω RDS(ON) and 300mV saturation voltage at 180mA, supporting efficient coil driving in low-power BLDC configurations. The regulator and protection circuitry ensure stable operation across –20°C to +100°C ambient, with junction temperature limited to 150°C and absolute max supply voltage of 8V.

Key Specifications

Pinout & Package

Available in SIP-4L (4-pin single-inline package) and SOT89-5L (5-pin surface-mount package); both integrate Hall sensor and dual output drivers in monolithic die. SIP-4L exposes Vdd, DO, DOB, and GND; SOT89-5L adds NC pin but maintains identical functional pin mapping for Vdd, DO, DOB, and GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Hall-effect BLDC fan controller applications.

Compared with A3921KLPTR-T and NCP1701A, AH291-YL-13 uniquely integrates Hall sensing, dual drivers, and autonomous lock-recovery in a single low-voltage package - reducing component count and eliminating firmware dependency for basic fan control.

Availability

AH291-YL-13 is available at Aetrix Electronics and suitable for server chassis cooling fans, network switch heat management, industrial PLC enclosure fans, and medical diagnostic equipment ventilation requiring stable component supply and RoHS-compliant green packaging.

Supply support for AH291-YL-13 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, computing, and consumer markets.

AH291 belongs to Diodes' Smart Motor Control product line, designed specifically for cost-sensitive, space-constrained BLDC fan applications requiring integrated Hall sensing and autonomous protection - not general-purpose motor drivers.

FAQ

What is the minimum supply voltage required for full magnetic functionality?

The AH291-YL-13 begins switching outputs at 1.8V, but its Hall sensor achieves specified magnetic operate/release characteristics only above 2.0V. Below 2.0V, rotor position detection may be unreliable, risking improper commutation or failure to start. Designers must ensure stable Vdd ≥2.0V during startup and operation for consistent Hall response.

How does the rotor-lock protection behave during continuous obstruction?

Upon detecting rotor stall, the AH291-YL-13 disables both DO and DOB outputs within 0.4 seconds, then enters a repeating 3-second cycle: 0.4s off followed by 2.6s of attempted restart. This continues until rotation resumes. No external reset or power cycle is needed - recovery is fully autonomous and hardware-based.

Can AH291-YL-13 drive three-phase BLDC motors?

No. The AH291-YL-13 contains only two complementary open-collector outputs (DO and DOB) and is explicitly designed for two-coil (single-phase or two-phase) BLDC fan topologies. It lacks the third output channel, timing logic, or commutation state machine required for three-phase motor control.

What is the purpose of the NC pin in the SOT89-5L package?

The NC pin in the SOT89-5L variant is an unconnected, unbonded terminal with no internal connection. It must remain floating - neither tied to GND nor routed on the PCB - to prevent noise coupling or unintended current paths. Its presence accommodates package standardization but provides no electrical function.