TC649EOA

The TC649 is a switch mode, fan speed controller for use with brushless DC fans. Temperature proportional speed control is accomplished using pulse width modulation (PWM). A thermistor (or other voltage output temperature sensor) connected to the VIN input furnishes the required control voltage of 1.25V to 2.65V (typical) for 0% to 100% PWM duty cycle. The TC649 automatically suspends fan operation when measured temperature (VIN) is below a user programmed minimum setting (VAS). An integrated Start-up Timer ensures reliable motor start-up at turn-on, coming out of shutdown mode, auto-shutdown mode or following a transient fault. In normal fan operation, a pulse train is present at SENSE (Pin 5). The TC649 features Microchip Technology’s proprietary FanSenseTM technology for increasing system reliability. A missing pulse detector monitors this pin during fan operation. A stalled, open or unconnected fan causes the TC649 to trigger its Start-up Timer once. If the fault persists, the FAULT output goes low, and the device is latched in its shutdown mode. The TC649 is available in the 8-pin PDIP, SOIC and MSOP packages and is available in the industrial and extended commercial temperature ranges.

• Temperature Proportional Fan Speed for Acoustic Control and Longer Fan Life
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range: - Fan Voltage Independent of TC649 Supply Voltage - Supports any Fan Voltage
• FanSense™ Fault Detection Circuits Protect Against Fan Failure and Aid System Testing
• Automatic Shutdown Mode for “Green” Systems
• Supports Low Cost NTC/PTC Thermistors
• Space Saving 8-Pin MSOP Package