AH284-PL-B Diodes Incorporated

AH284 HALL-EFFECT SMART FAN MOTOR CONTROLLER Description Pin Assignments The AH284 is a single-chip solution for driving two-coil (Top View) (Top View) brushless direct current (BLDC) fans and motors. The device includes a Hall-effect sensor, dynamic offset correction and 284 Vdd 1 5 NC two complementary open-drain output drivers with internal 1 : Vdd Zener diode protection. 284 2 : DO GND 2 To help protect the motor coils, the AH284 provides Rotor 3 : DOB Lock Protection which shuts down output drives if rotor lock is DO 3 74 DOB 4 : GND detected. The device automatically re-starts when the rotor 12 3 4 SOT89-5L lock is removed. SIP-4L The AH284 is available in SIP4 and SOT89-5L packages. Features Applications Single-chip solution Two-coil BLDC cooling fans Operating Voltage: 3.8V to 20V Low to medium voltage, low power BLDC motors Built-in Hall sensor and input amplifier Rotor Lock Protection (Lock detection, output shutdown and automatic re-start) Built-in Zener protection for output driver Average output current up to 500mA Packages: SIP-4L and SOT89-5L Green Molding Compound Typical Application Circuit (Note 1) 12V D2 V dd D1 284 L2 L1 12 3 4 GND DOB C3 D3 DO R1 R2 C1 C2 Notes: 1. Typically it is recommended to us a 56 Ohm resistor for R1 and R2 and a 2.2F E-Cap capacitor for C1, C2 and C3. These values may need to be optimized depending on the coils used. To help with IC protection its advised to add a Zener diode between Vdd and ground. The Zener diode should be chosen to help prevent the supply voltage exceeding the maximum rating of the device. 1 of 10 June 2010 AH284 Diodes Incorporated www.diodes.com Document number: DS31051 Rev. 11 - 2 AH284 HALL-EFFECT SMART FAN MOTOR CONTROLLER Pin Descriptions Pin Name Description Vdd Input Power DO Output Pin DOB Output Pin GND Ground NC Not Connected Functional Block Diagram Vdd Lock detect, shutdown and automatic re-start Regulator DO Hall Plate Control Logic Amp. DOB GND 2 of 10 June 2010 AH284 Diodes Incorporated www.diodes.com Document number: DS31051 Rev. 11 - 2