Closed Loop Brushless Motor Adapter Using MC33039

The MC33039 is a high performance closed–loop speed control adapter specifically designed for use in brushless DC motor control systems. Implementation will allow precise speed regulation without the need for a magnetic or optical tachometer. This device contains three input buffers each with hysteresis for noise immunity, three digital edge detectors, a programmable monostable, and an internal shunt regulator. Also included is an inverter output for use in systems that require conversion of sensor phasing. Although this device is primarily intended for use with the MC33035 brushless motor controller, it can be used cost effectively in many other closed–loop speed control applications.



  • Digital Detection of Each Input Transition for Improved Low Speed Motor Operation
  • TTL Compatible Inputs With Hysteresis
  • Operation Down to 5.5 V for Direct Powering from MC33035 Reference
  • Internal Shunt Regulator Allows Operation from a Non-Regulated Voltage Source
  • Inverter Output for Easy Conversion between 60°/300° and 120° /240° Sensor   Phasing Conventions