3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING

The A8904SLB and A8904SLP are three-phase brushless dc motor controller/drivers designed for applications where accurate control of high speed motors is required. The three half-bridge outputs are low on-resistance n-channel DMOS devices capable of driving up to 1.2 A. The A8904 provides complete, reliable, self-contained back-EMF sensing, motor startup and running algorithms. A programmable digital frequency-locked loop speed control circuit together with the linear current control circuitry provides precise motor speed regulation.

Features
■ Pin-for-pin replacement for A8902CLBA
■ Startup commutation circuitry
■ Sensorless commutation circuitry
■ Option of external sector data tachometer signal
■ Option of external speed control
■ Oscillator operation up to 20 MHz
■ Programmable overcurrent limit
■ Transconductance gain options: 500 mA/V or 250 mA/V
■ Programmable watchdog timer
■ Directional control
■ Serial Port Interface
■ TTL-compatible inputs
■ System diagnostics data out ported in real time
■ Dynamic braking through serial port or external terminal