TC654EUN

The TC654EUN is a Dual SMBus™ PWM Fan Speed Controller with fan fault detection and FanSense technology for use with brushless DC fans. This device implements temperature proportional fan speed control which lowers acoustic fan noise and increases fan life. The voltage at VIN represents temperature and is typically provided by an external thermistor or voltage output temperature sensor. The PWM output is adjusted between 30 and 100% based on the voltage at VIN. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need for an external thermistor. If VIN is not connected, it will start driving the fan at a default duty cycle of 39.33%. In normal fan operation, pulse trains are present at SENSE1 and SENSE2. It uses the pulse to calculate the fan revolutions per minute. The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below the user-programmable threshold causes the TC654 to assert a logic low alert signal.

• Temperature proportional fan speed for reduced acoustic noise and longer fan life
• FanSense™ Protects against fan failure and eliminates the need for 3-wire fans
• Efficient PWM fan drive
• Provides RPM data
• 2-wire SMBus™ compatible interface
• Software controlled shutdown mode for green systems
• Supports NTC/PTC thermistors