A4931 3-Phase Brushless DC Motor Pre-Driver Features and Benefits Description Drives 6 N-channel MOSFETs The A4931 is a complete 3-phase brushless DC motor pre-driver. Synchronous rectification for low power dissipation The device is capable of driving a wide range of N-channel Internal UVLO and thermal shutdown circuitry power MOSFETs and can support motor supply voltages up to Hall element inputs 30 V. Commutation logic is determined by three Hall-element PWM current limiting inputs spaced at 120. Dead time protection Other features include fixed off-time pulse width modulation FG outputs (PWM) current control for limiting inrush current, locked-rotor Standby mode protection with adjustable delay, thermal shutdown, overvoltage Lock detect protection monitor, and synchronous rectification. Internal synchronous Overvoltage protection rectification reduces power dissipation by turning on the appropriate MOSFETs during current decay, thus shorting Package: 28-contact QFN (ET package) the body diode with the low R MOSFET. Overvoltage DS(on) protection disables synchronous rectification when the motor pumps the supply voltage beyond the overvoltage threshold during current recirculation. The A4931 offers enable, direction, and brake inputs that can control current using either phase or enable chopping. Logic outputs FG1 and FG2 can be used to accurately measure motor rotation. Output signals toggle state during Hall transitions, providing an accurate speed output to a microcontroller or speed control circuit. Approximate Scale 1:1 Operating temperature range is 20C to 105C. The A4931 is supplied in a 5 mm 5 mm, 28-terminal QFN package with exposed thermal pad. This small footprint package is lead (Pb) free with 100% matte tin leadframe plating. Typical Application 0.1 F 0.1 F 0.1 F 0.1 F 2 k CLD HBIAS CP1 CP2 VCP VBB V V IN IN GHA SA FG1 A4931 GLA M FG2 System GHB Control BRAKEZ Logic SB GLB ENABLE GHC DIR SC GLC SENSE GND HA+ HA HB+ HB HC+ HC 4931-DS, Rev. 6A4931 3-Phase Brushless DC Motor Pre-Driver Selection Guide Part Number Packing Package A4931METTR-T 1500 pieces per reel 5 mm x 5 mm, 0.90 mm nominal height QFN Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Load Supply Voltage V 38 V BB Motor Phase Output S t < 500 ns 3 V X w Hall Input V DC 0.3 to 7 V Hx Logic Input Voltage Range V 0.3 to 7 V IN Operating Ambient Temperature T Range M 20 to 105 C A Maximum Junction Temperature T (max) 150 C J Storage Temperature T 40 to 150 C stg Thermal Characteristics Characteristic Symbol Test Conditions* Rating Units Package Thermal Resistance, Junction R 4-layer PCB based on JEDEC standard 32 C/W JA to Ambient Package Thermal Resistance, Junction R 2 C/W JP to Exposed Pad *For additional information, refer to the Allegro website. Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com