The TC646BEOA is a switch-mode PWM Fan Speed Controller with an auto-shutdown for use with brushless DC fans. Temperature proportional speed control is accomplished using pulse width modulation. A thermistor connected to the VIN input furnishes the required control voltage of 1.25 to 2.65V for 0 to 100% PWM duty cycle. It automatically suspends fan operation when measured temperature is below user programmed minimum setting. 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. It features 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 TC646 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.
● Temperature proportional fan speed for acoustic control 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
● Over-temperature indication
