TC664

Features:

• 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
• Over Temperature Detection (TC665)
• Efficient PWM Fan Drive
• Provides RPM Data
• 2-Wire SMBus™-Compatible Interface
• Supports Any Fan Voltage
• Software Controlled Shutdown Mode for "Green" Systems
• Supports Low Cost NTC/PTC Thermistors
• Space Saving 10-Pin MSOP Package
• Temperature Range: -40°C to +85ºC




Application

• Personal Computers & Servers
• LCD Projectors
• Datacom & Telecom Equipment
• Fan Trays
• File Servers
• Workstations
• General Purpose Fan Speed Control




Pinout






Specifications

VDD......................................................................................6.5 V
Input Voltages ....................................... -0.3 V to (VDD + 0.3 V)
Output Voltages .................................... -0.3 V to (VDD + 0.3 V)
Storage temperature .....................................-65°C to +150°C
Ambient temp. with power applied ................-40°C to +125°C
Maximum Junction Temperature, TJ ................................. 150°C
ESD protection on all pins.................................................. 4 kV
*Notice: Stresses above those listed under "Maximum ratings"
may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied. Exposure
to maximum rating conditions for extended periods may
affect device reliability.

Parameter Name	Value
Typical Accuracy (°C)	Depends on external thermistor
Over Temp Alert	NO
SM Bus	yes
Predictive Fan Fault	yes
Max. Supply Current (A)	320
Max. Accuracy @ 25°C (°C)	Depends on external thermistor
Integrated Temp Sensor	No
Fan Sense	Yes
External Temp Input	Yes
Auto Shutdown	No
Device Description	Single SMBus Fan Manager
Temp Range (°C)	-40 to +85
Vcc Range (V)	+3.0 to +5.5

Description

The TC664/TC665 devices are PWM mode fan speed controllers with FanSense technology for use with brushless DC fans. These devices implement temperature proportional fan speed control which lowers acoustic fan noise and increases fan life. The voltage at VIN (Pin 1) represents temperature and is typically provided by an external thermistor or voltage output temperature sensor. The PWM output (VOUT) 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, the TC664/TC665 will start driving the fan at a default duty cycle of 39.33%. See Section 4.3, "Fan Startup", for more details).

In normal fan operation, a pulse train is present at the SENSE pin (Pin 8). The TC664/TC665 use these pulses to calculate the fan revolutions per minute (RPM). 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 TC664/ TC665 to assert a logic low alert signal (FAULT). The default threshold value is 500 RPM. Also, if this condition occurs, FF (bit 0<0>) in the Status Register will also be set to a '1'.

The TC664 is a single PWM mode fan speed controller with FanSense™ TM technology for use with brush-less DC motors. The device allows temperature proportional speed control and therefore accomplishes lower acoustic fan noise and longer fan life. The TC664 reads the voltage provided by an external ther-mistor (or voltage output temperature sensor) and adjusts a 30% to 100% PWM duty cycle output to the fan with respect to the input temperature voltage. The PWM duty cycle can also be programmed via SMBus to allow fan speed control without the need of an external thermistor.

In normal fan operation, pulse trains are present at the SENSE pin. These pulses are used to calculate the fan RPM. 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 TC664 to assert a logic low alert signal (FAULT). Thedefault value is 500RPM. The TC664 consumes only 0.3mA during operation and can also enter a low-power shutdown mode by setting the appropriate bit in the configuration register.