PWM Fan Speed Controllers
M TC642B/TC647B
PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense™ Technology for Fault Detecti...
Description
M TC642B/TC647B
PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense™ Technology for Fault Detection
Features
Temperature-Proportional Fan Speed for Acoustic Noise Reduction and Longer Fan Life
Efficient PWM Fan Drive 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC642B/TC647B Supply Voltage
- Supports any Fan Voltage FanSense™ Fault Detection Circuit Protects
Against Fan Failure and Aids System Testing Shutdown Mode for "Green" Systems Supports Low Cost NTC/PTC Thermistors Over-Temperature Indication (TC642B only) Fan Auto-Restart Space-Saving 8-Pin MSOP Package
Applications
Personal Computers & Servers LCD Projectors Datacom & Telecom Equipment Fan Trays File Servers General Purpose Fan Speed Control
Package Types
MSOP, PDIP, SOIC
VIN CF VMIN GND
1 2 3 4
TC642B TC647B
8 VDD 7 VOUT 6 FAULT 5 SENSE
Description
The TC642B/TC647B devices are new versions of the existing TC642/TC647 fan speed controllers. These devices are switch mode, fan speed controllers that incorporate a new fan auto-restart function. Temperature-proportional speed control is accomplished using pulse width modulation. A thermistor (or other voltage output temperature sensor) connected to the VIN input supplies the required control voltage of 1.20V to 2.60V (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, ...
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