TC647BEUA

The TC647BEUA is a switch mode PWM Fan Speed Controller with fan restart and FanSense™ technology for fault detection. Temperature-proportional speed control is accomplished using pulse width modulation. A thermistor connected to the VIN input supplies the required control voltage of 1.2 to 2.6V typical for 0 to 100% PWM duty cycle. Minimum fan speed is set by a simple resistor divider on the VMIN input. An integrated Start-Up Timer ensures reliable motor start-up at turn-ON, coming out of shutdown mode or following a transient fault. A logic-low applied to VMIN causes fan shutdown. The TC647B also feature Microchip Technology's proprietary FanSense™ technology for increasing system reliability. In normal fan operation, a pulse train is present at SENSE. A missing-pulse detector monitors this pin during fan operation. A stalled, open or unconnected fan causes the TC647B device to turn the VOUT output on full. If the fault persists, the FAULT output goes low.

• Temperature proportional fan speed for acoustic noise reduction and longer fan life
• Efficient PWM fan drive
• FanSense™ Fault detection circuit protects against fan failure and aids system testing
• Shutdown mode for green systems
• Supports NTC/PTC thermistors
• Fan auto-restart