NOT RECOMMENDED FOR NEW DESIGN USE AH9485/AH9486 AH5798 SINGLE PHASE HALL EFFECT LATCH SMART FAN MOTOR CONTROLLER Description Pin Assignments The AH5798 is a single chip solution for driving single-coil ( Top View ) brushless direct current (BLDC) fans and motors. The integrated full-bridge driver output stage uses soft switching Vdd 1 FG 5 to minimize audible switching noise and electromagnetic interference (EMI) providing a low noise solution. NC 2 Vss To help protect the motor coil, the AH5798 provides Rotor Lock Protection which shuts down output drive if rotor lock is O1 3 74 O2 detected. The device automatically re-starts when the rotor lock is removed. Over temperature shutdown provides SOT89-5L thermal protection for the device. A Tachometer output is provided by open-drain Frequency ( Top View) Generator (FG) Pin which allows external interface to monitor motor rotation or speed. The FG output is the magnetic FG 1 5 Vdd change frequency. The AH5798 is available in space saving SOT89-5L and 2 Vss thinner TSOT25 packages. 3 4 O1 O2 Features TSOT25 Supports single-coil full-wave DC fan drivers Built-in Hall sensor and input amplifier Operating Voltage: 1.8V to 5.5V Applications Soft switching for low noise DC fan motor applications Rotor Lock Protection (Lock detection, output shutdown 3.3V / 5V Min. BLDC Cooling Fans and automatic re-start) Netbook/ Notebook BLDC fans Thermal protection Low Voltage/ Low Power BLDC Motors Tachometer (FG) output No external timing capacitor - Reduces the numbers of external components required Low profile packages: SOT89-5L and TSOT25 Green Molding Compound 1 of 11 January 2021 AH5798 Diodes Incorporated www.diodes.com Document number: DS32001 Rev. 3 - 3 AH5798 SINGLE PHASE HALL EFFECT LATCH SMART FAN MOTOR CONTROLLER Typical Application Circuit SYSTEM POWER 10Kohm SYSTEM V FG FG dd POWER D1 C1 Dz O1 AH5798 O2 V SS * Reverse connection of power supply may damage the device. To prevent reverse power damage, a protection (reverse blocking) Diode D1 is needed between power supply and Vdd terminal. If a reverse power protection diode D1 is used, there is no current return path to power supply, so it is necessary to follow measures such as below. - Connect Dz (Zener diode) between Vdd and Vss terminal, to prevent voltage exceeding the absolute maximum rating of the device. - Connect a capacitor C1 between Vdd and Vss terminal, to complete the current return path to power supply. The AH5798 has an open-drain tachometer FG output that follows the magnetic change frequency. Typically, a pull-up resistor of 10k is recommended from FG pin to the supply voltage. Pin Descriptions Pin Name Description Vdd Power Supply Pin Vss Ground Pin O1 Output Driving & Sinking Pin 1 O2 Output Driving & Sinking Pin 2 NC No Connection FG Frequency Generator (Note 1) Notes: 1. The FG is the same as the magnetic change frequency. 2 of 11 January 2021 AH5798 Diodes Incorporated www.diodes.com Document number: DS32001 Rev. 3 - 3