TC647

Features:

• Temperature Proportional Fan Speed for Acoustic Control and Longer Fan Life
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC647 Supply Voltage
- Supports any Fan Voltage
• FanSense™ Technology Fault Detection Circuits Protect Against Fan Failure and Aid System Testing
• Shutdown Mode for "Green" Systems
• Supports Low Cost NTC/PTC Thermistors
• Space Saving 8-Pin MSOP Package




Application

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




Pinout






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 SensorNoFan SenseYesExternal Temp InputYesAuto ShutdownNoDevice DescriptionFan ManagerTemp Range (°C)-40 to +85Vcc 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 TC647 is a switch mode fan speed controller for use with brushless DC motors. Temperature proportional speed control is accomplished using pulse width modulation. 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. 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, Pin 3, causes fan shutdown. The TC647 also features Microchip Technology's proprietary FanSense™ ? technology for increasing system reliability. In normal fan operation, a pulse train is present at SENSE, Pin 5, indicating normal operation. A Missing-pulse Detector monitors this pin during normal fan operation. A stalled, open, or unconnected fan causes the TC647 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. The TC647 is available in a standard 8-Pin PDIP, MSOP and SOIC packages. Commercial and industrial temperature ranges are available in both package options.