a3520 general features The a3520 is a DC motor controller IC, providing a single chip solution for a wide range of tasks including power supply, motor control and high level system control. The IC's components enable parallel execution of system functions such as PWM input capture, current limit monitoring, bridge clock generation, etc., while reducing the IC's MCU's load and memory requirements. IC Features MCU Features Operating VCC range from 5-18V On-chip 25MHz ±1% oscillator 10bit AD Converter with 8-channel multiplexer On-chip 3.3V/5mA regulator On-chip programmable 0.7V to 2.7V/10mA regulator, suitable for driving passive hall elements VCC monitor On-chip temperature sensor 6 gate driver outputs with pull and dump resistors PWM input capture unit to decode duty cycles of external signals Open drain signal output, over current protected Two wire interface 0-VCC high voltage PWM-output ready to drive inrush current protection transistors Up to 10 pins usable as GPIO Spread spectrum PWM support via software Non-overlapping bridge clock generator with programmable deadtime Programmable current limit analog comparator with programmable hysteresis (Hall sensor, Phase voltage feedback) Standard compatible MCU Powerful single cycle instruction set (only RAM access and branches need two cycles) 25MHz MCU clock 12 prioritized interrupt levels 256Byte RAM 4kByte Pseudo-MTP program memory Four 16bit timers with pre-scaler Two 8 bit timers with pre-scaler Hardware watchdog timer On-chip debugging support Fast RAM-based development support Two wire programming and debugging interface Package: QFN28 The 28 pin 4x4mm QFN package option is best suited for small board designs. example application schematics Only a few external components are needed to build a simple motor application: +12V power supply 100nF +3.3V output VCC VIO DAC 100nF 100nF VD 100nF VA 100nF VREF PWM input PD1H PD1L PD2H PD2L CIN PWMIN VH VCC TACHO output PD2H PD2L 100nF a3520 * HC1 HC2 TACH programming interface PCL PDA GND GND Hall Sensor GPIO1 GPIO2 ADC1 ADC2 ADC3 * external components needed to meet 2000V machine model ESD protection level Fig.1 Simplified single phase application schematic +12V power supply 100nF +3.3V output VCC VIO 100nF 100nF PD1H PD1L PD2H PD2L GPIO1 GPIO2 VD 100nF VA 100nF VREF PWM input a3520 * TACHO output PD2L PD3L PD2H PD2L PD3H PD3L VH HC1 HC2 ADC1 ADC2 TACH PCL PDA PD3H CIN PWMIN VCC PD2H DAC Common U V W U GND Common W V ADC3 GND * external components needed to meet 2000V machine model ESD protection level Fig. 2 Simplified sensorless three phase application schematic Control algorithms for different types of motors single phase, three phase with and without sensors are implemented as MCU programs. All six high voltage outputs can be used to drive bridge transistors directly. The on chip bridge driving logic includes dead time and shout through protection for each bridge transistor pair.