MTD6508-E/NA [Microchip]

The MTD6508 device is a 3-phase full-wave sensorless driver for brushless DC (BLDC) motors. The MTD6508 offers start-up output slew rate and PWM duty cycle control that allow designer to balance between acoustic performance and reliability. With the adaptive features, parameters and wide range of power-supplies (2V to 5.5V), the MTD6508 is intended to cover a broad range of motor characteristics, while requiring minimum external components. Speed control can be achieved through either power supply modulation (PSM) or pulse-width modulation (PWM). The compact packaging and the minimal bill-of-material make the MTD6508 device extremely cost efficient in fan applications. For example, the CPU cooling fans in notebook computers require designs that provide low acoustic noise, low mechanical vibration, and are highly efficient. The frequency generator (FG) output enables precision speed control in closed-loop applications. The MTD6508 device includes Lockup Protection mode to turn off the output current when the motor is in a lock condition, with an automatic recovery feature to restart the fan when the lock condition is removed. Motor overcurrent limitation and thermal shutdown protection are included for safety enhanced operations.

• Output PWM Slew Rate Control Programmable with an External Resistor for Start-up (Adjustable version) 
• Phase Target Selection for Regulation (Adjustable Version)
• Start-up Strength Selection (Adjustable Version)
• 180° Sinusoidal Drive, for high efficiency and low acoustic noise
• Position Sensorless BLDC Drivers (No Hall-effect sensor required)
• Integrated Power Transistors
• Supports 2V to 5.5V Power Supplies
• Programming Resistor (RPROG) setting to fit motor constant (Km) range from 3.25 mV/Hz to 52 mV/Hz
• Direction Control: - Forward direction: connect DIR pin to GND or leave floating - Reverse direction: connect DIR pin to VBIAS
• Speed Control through Power Supply Modulation (PSM) and/or Pulse-Width Modulation (PWM)
• Built-in Frequency Generator (FG Output Signal)
• Built-in Lockup Protection and Automatic Recovery Circuit
• Built-in Overcurrent Limitation
• Built-in Thermal Shutdown Protection
• No External Tuning Required