TC648
Fan Speed Controller with Auto-Shutdown
and Over-Temperature Alert
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 TC648
Supply Voltage
-Supports any Fan Voltage Over-temperature Fault Detection Automatic Shutdown Mode for “Green” Systems Supports Low Cost NTC/PTC Thermistors Space Saving 8-Pin MSOP Package Applications Power Supplies
Computers
Portable Computers
Telecom Equipment
UPSs, Power Amps
General Purpose Fan Speed Control Available Tools Fan Controller Demonstration Board (TC642DEMO) Fan Controller Evaluation Kit (TC642EV) Package Types
SOIC/PDIP/MSOP
VIN 1 CF 2 VAS 3 GND 4 TC648 8 VDD 7 VOUT 6 OTF 5 NC General Description
The TC648 is a switch mode, fan speed controller for
use with brushless DC fans. Temperature proportional
speed control is accomplished using pulse width modulation (PWM). A thermistor (or other voltage output
temperature sensor) connected to the VIN input
furnishes the required control voltage of 1.25V to 2.65V
(typical) for 0% to 100% PWM duty cycle. The TC648
can be configured to operate in either auto-shutdown or
minimum speed mode. In auto-shutdown mode, fan …