AH5795-FDC-7 Diodes Incorporated

AH5795 SINGLE PHASE HALL EFFECT LATCH SMART FAN MOTOR CONTROLLER Description Pin Assignments The AH5795 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 1 6 PWM FG to minimize audible switching noise and electromagnetic interference (EMI) providing a low noise solution. 2 5 Vss Vdd Motor speed can be controlled by either changing the duty ratio of the PWM signal at the PWM pin or by varying the 3 4 O1 O2 supply voltage at Vdd pin. To help protect the motor coil, the AH5795 provides Rotor TSOT23-6 Lock Protection which shuts down the output drive if rotor lock is detected. The device automatically re-starts when the rotor lock is removed. Over temperature shutdown provides (Top View) thermal protection for the device. PWM 1 6 FG A Tachometer output is provided by open-drain Frequency Generator (FG) Pin which allows external interface to monitor 2 5 Vdd O2 motor rotation or speed. The FG output is the magnetic change frequency. 3 4 O1 Vss The AH5795 is available in space saving and low profile DFN2020C-6 TSOT23-6 and DFN2020C-6 packages. Features Applications Supports single-coil full-wave BLDC fan drivers Built-in Hall sensor and input amplifier 3.3V / 5V BLDC Cooling Fans Operating voltage: 1.8V to 6V Netbook/ Notebook BLDC fans Speed control methods Instruments cooling fans o Vdd voltage speed control (PWM pin tied to Vdd) Low Voltage/ Low Power BLDC Motors o PWM signal speed control via PWM pin Soft switching for low noise DC fan motor applications Rotor Lock Protection (Lock detection, output shutdown and automatic re-start) Toff clear when PWM is low for greater than 65ms Thermal protection Tachometer (FG) output No external timing capacitor - Reduces the numbers of external components required Low profile package: TSOT23-6 and DFN2020C-6 Green Molding Compound (No Br, Sb) (Note 1) Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at AH5795 SINGLE PHASE HALL EFFECT LATCH SMART FAN MOTOR CONTROLLER Typical Application Circuit SYSTEM POWER D1 C1 Dz 10Kohm Vdd FG FG PWM O1 AH5795 PWM signal for speed control O2 Vss Pin Descriptions Pin Name Description V Power supply pin dd V Ground pin SS O1 Output driving & sinking pin O2 Output driving & sinking pin PWM PWM signal input pin for speed control FG Frequency Generator (Note 2) Notes: 2. The FG output is the same as the magnetic change frequency. 2 of 13 August 2011 AH5795 Diodes Incorporated www.diodes.com Document number: DS35277 Rev. 1 - 2 NEW PRODUCT