Variable speed is adjusted by varying the duty cycle to the PWM control input pin. The analog control pin can be used to interface with a thermistor when the PWM input control is not needed. Rotor speed is reported on TACH. Rotor lock is reported on a separate ALARM pin. Soft switching reduces audible noise. Current limit and thermal protections are also provided. The 40V MOS output predrivers can source or sink 100mA.