A4934: Three-Phase Sensorless Fan Driver


This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available. Date of status change: October 31, 2011.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the A4941.

The A4934 three-phase motor driver incorporates BEMF sensing to eliminate the requirement for Hall sensors in fan applications.

A pulse wave modulated (PWM) input is provided to control motor speed, allowing system cost savings by eliminating external variable power supply. PWM input can also be used as an on/off switch to disable motor operation and place the IC into a low power standby mode.

The A4934 soft switching settings are designed for lower inductance or lower speed motors. For higher inductance or higher speed motors consider using the pin-compatible A4941.

Top Features

  • Sensorless (no Hall sensors required)
  • Soft switching for reduced audible noise
  • Minimal external components
  • PWM speed input
  • FG speed output
  • Low power standby mode
  • Lock detection
  • Optional overcurrent protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
A4934GLPTR-T 16-lead TSSOP -40°C to 105°C Yes View Data Discontinued Contact your
local sales rep
Distributor Stock

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The A4934 is provided in a 16-pin TSSOP package (suffix LP) with an exposed thermal pad. It is lead (Pb) free, with 100% matte tin leadframe plating.

LP 16-pin TSSOP