TC649 PWM Fan Speed Controller with Auto-Shutdown and FanSense Technology Features Package Types Temperature Proportional Fan Speed for Acoustic SOIC/PDIP/MSOP Control and Longer Fan Life Efficient PWM Fan Drive V V 18 IN DD 3.0V to 5.5V Supply Range: V C27 OUT - Fan Voltage Independent of TC649 F TC649 Supply Voltage V FAULT AS36 - Supports any Fan Voltage SENSE GND45 FanSense Fault Detection Circuits Protect Against Fan Failure and Aid System Testing Automatic Shutdown Mode for Green Systems Supports Low Cost NTC/PTC Thermistors General Description Space Saving 8-Pin MSOP Package The TC649 is a switch mode, fan speed controller for use with brushless DC fans. Temperature proportional Applications speed control is accomplished using pulse width mod- Power Supplies ulation (PWM). A thermistor (or other voltage output Computers temperature sensor) connected to the V input fur- IN nishes the required control voltage of 1.25V to 2.65V File Servers (typical) for 0% to 100% PWM duty cycle. The TC649 Portable Computers automatically suspends fan operation when measured Telecom Equipment temperature (V ) is below a user programmed IN UPSs, Power Amps minimum setting (V ). An integrated Start-up Timer AS General Purpose Fan Speed Control ensures reliable motor start-up at turn-on, coming out of shutdown mode, auto-shutdown mode or following a Available Tools transient fault. Fan Controller Demonstration Board (TC642DEMO) In normal fan operation, a pulse train is present at SENSE (Pin 5). The TC649 features Microchip Fan Controller Evaluation Kit (TC642EV) TM technology for Technologys proprietary FanSense increasing system reliability. 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 out- put goes low, and the device is latched in its shutdown mode. See Section 5.0, Typical Applications, for more information and system design guidelines. The TC649 is available in the 8-pin PDIP, SOIC and MSOP packages and is available in the industrial and extended commercial temperature ranges. 2001-2012 Microchip Technology Inc. DS21449D-page 1TC649 Functional Block Diagram V TC649 IN V DD PWM + Control V Logic OUT C F 3 x T PWM Timer Clock Generator FAULT Start-up Timer V AS + SHDN Missing Pulse Detect + V SHDN SENSE 10k GND 70mV (typ.) DS21449D-page 2 2001-2012 Microchip Technology Inc. +