TC649

Features:

• Temperature Proportional Fan Speed for AcousticControl 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




Application

• Power Supplies
• Computers
• File Servers
• Portable Computers
• Telecom Equipment
• UPSs, Power Amps
• General Purpose Fan Speed Control




Specifications

Parameter NameValueTypical Accuracy (°C)Depends on external thermistorOver Temp AlertNOSM BusNOPredictive Fan FaultNOMax. Supply Current (A)1000Max. Accuracy @ 25°C (°C)Depends on external thermistorIntegrated Temp SensorYesFan SenseYesExternal Temp InputNoAuto ShutdownYesDevice DescriptionFan ManagerTemp Range (°C)-40 to +85Vcc Range (V)+3.0 to +5.5

Parameter Name	Value
Typical Accuracy (°C)	Depends on external thermistor
Over Temp Alert	NO
SM Bus	NO
Predictive Fan Fault	NO
Max. Supply Current (A)	1000
Max. Accuracy @ 25°C (°C)	Depends on external thermistor
Integrated Temp Sensor	Yes
Fan Sense	Yes
External Temp Input	No
Auto Shutdown	Yes
Device Description	Fan Manager
Temp Range (°C)	-40 to +85
Vcc Range (V)	+3.0 to +5.5

Supply Voltage .........................................................6V
Input Voltage, Any Pin.... (GND  0.3V) to (VDD +0.3V)
Package Thermal Resistance:
PDIP (RJA) ......................................................125°C/W
SOIC (RJA) .....................................................155°C/W
MSOP (RJA) ....................................................200°C/W
Specified Temperature Range ........... -40°C to +125°C
Storage Temperature Range.............. -65°C to +150°C

Description

The TC649 is a switch mode fan speed controller for use with brushless DC motors. Temperature proportional speed control is accomplished using pulse width modulation(PWM). A thermistor (or other voltage output temperature sensor) connected to VIN 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, or following a transient fault. In normal fan operation, a pulse train is present at SENSE, Pin 5. 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. See the Applications section for more information and system design guidelines. The TC649 is packaged in a space-saving 8-Pin PDIP, MSOP or a SOIC package and is available in the industrial temperature range.