Diodes Incorporated AH5798-YG-13

Overview

AH5798-YG-13 from Diodes Incorporated is a single-phase Hall-effect latch smart fan motor controller IC integrating a Hall sensor, amplifier, full-bridge driver, rotor lock protection, thermal shutdown, and open-drain tachometer (FG) output. It drives single-coil BLDC fans at 1.8V–5.5V supply, delivers up to 800mA peak output current, uses soft switching to suppress audible noise and EMI, and supports automatic restart after rotor lock detection - deployed in 3.3V/5V notebook cooling fans.

For engineers reviewing the AH5798-YG-13 datasheet, AH5798-YG-13 pinout, AH5798-YG-13 application, or AH5798-YG-13 equivalent, key selection criteria include integrated Hall sensing, FG output timing fidelity, soft-switching EMI performance, rotor lock recovery behavior, and dual-package availability (SOT89-5L/TSOT25) for thermal and board-space constrained designs.

Technical Context

The AH5798 implements a closed-loop commutation control architecture using an on-chip Hall sensor to detect magnetic pole transitions and drive complementary O1/O2 outputs with soft-switching timing. Its logic monitors FG frequency to detect stalled rotor conditions and triggers automatic shutdown/restart sequences without external intervention.

It operates across –40°C to +105°C ambient, supports 100μs typical output switching slope under 50Ω load, and delivers FG output synchronized to magnetic change frequency - not motor rotation period - with 5μA max leakage and 0.4V max low-level voltage at 5mA sink current.

Key Specifications

Pinout & Package

Available in two thermally optimized packages: SOT89-5L (5-pin, exposed thermal pad) and TSOT25 (5-pin, thinner profile). Both packages integrate the Hall sensor die with precise magnetic axis alignment relative to pin 1 (O2) and pin 5 (Vdd) as marked on top view.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AH5798-YG-13, AH9485 adds programmability at the cost of pin count and design complexity, while AH9486 delivers identical functionality with tighter thermal and magnetic specs - making it the preferred upgrade path for lifecycle continuity without layout changes.

Availability

AH5798-YG-13 is available at Aetrix Electronics and suitable for 3.3V notebook cooling fans, 5V netbook BLDC fans, and low-voltage embedded motor control applications requiring stable component supply, RoHS compliance, and long-term industrial availability.

Supply support for AH5798-YG-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 analog solutions for industrial, computing, and consumer markets.

The AH5798 belongs to Diodes' Smart Fan Controller product line, designed specifically to replace multi-component BLDC fan drive solutions with integrated Hall sensing, soft-switching drivers, and intelligent protection - targeting compact, low-noise thermal management in portable electronics.

FAQ

What is the function of the NC pin on the AH5798-YG-13 in SOT89-5L package?

Pin 3 in the SOT89-5L package is designated NC (No Connection) and must remain electrically unconnected. It is not bonded internally and has no circuit function. PCB layout must omit copper trace, solder mask opening, or via at this location to prevent unintended coupling or mechanical stress on the die bond wire.

How does the FG output relate to motor speed in the AH5798-YG-13?

The FG output pulses at the magnetic pole transition frequency - not motor RPM. For a 2-pole BLDC fan, one FG cycle corresponds to one full motor revolution; for multi-pole rotors, FG frequency equals RPM × (number of pole pairs). Accurate speed calculation requires knowing the motor's pole count and applying appropriate scaling in firmware.

Can the AH5798-YG-13 operate without an external reverse-voltage protection diode?

No. The datasheet explicitly warns that reverse supply connection may damage the device. A series blocking diode (D1) is mandatory. When used, a Zener clamp (Dz) between Vdd and Vss and a bypass capacitor (C1) are also required to provide current return path and prevent Vdd overvoltage during reverse polarity events.

What thermal derating applies to the AH5798-YG-13 in SOT89-5L package at 85°C ambient?

In SOT89-5L, maximum power dissipation drops linearly from 800mW at 25°C to 416mW at 85°C ambient, based on θ_JA = 156°C/W. This limits continuous output current to approximately 550mA at 85°C - design must verify junction temperature using P_D = I_OUT² × R_DS(on) + I_DD × V_DD and ensure T_J stays below 145°C.