Allegro MicroSystems A4945
The A4945 and A4949 three phase motor drivers incorporate sinusoidal drive to minimize audible noise and vibration for medium power fans. This allows system cost savings by eliminating an external variable power supply. The A4945 and A4949 are supplied in an 8-pin SOICN with exposed power pad (suffix LJ), and an 8-pin SOICN (suffix L) for wave solder applications.| Part No. | A4945 |
|---|---|
| Datasheet | A4945 Download |
| Manufacturer |  Allegro MicroSystems |
| Description | Three Phase Sensorless Sinusoidal Fan Driver |
| Buy | Stock & Price |
FEATURES AND BENEFITS
● 180° sinusoidal drive for low audible noise● High efficiency control algorithm
● Sensorless operation
● Analog Speed input (A4945)
● PWM Speed input (A4949)
● Wide supply voltage range
● FG speed output
● Lock detection
● Overcurrent protection
● Soft start
● Short circuit protection PACKAGES:
DESCRIPTION
A Speed input is provided to control motor speed. Alternatively, power supply modulation down to 4 V can be used to adjust motor speed. Both packages are lead (Pb) free with 100% matte-tin leadframe plating. 8-pin SOICN 8-pin SOICN with exposed thermal pad (L package) (LJ package) Not to scale Functional Block Diagram VBB 50 kΩ Speed Demand Input PWM 100 kΩ Duty Cycle FG A4949 device shown TSD IDC Protection VREG VREF VBB Duty Measure IDC Sinusoidal Drive 6 Wave Shape Gate Drive Startup Logic 30 kHz PWM OSC OUTA OUTB OUTC GND Position Detect OUTA OUTB OUTC PAD LJ package only VSUPPLY CVREF 0.1 µF X5R 10 V CVBB 10 µF M Speed Demand A4945-DS, Rev. 9 MCO-0000480...
