TC664/TC665 SMBus PWM Fan Speed Controllers With Fan Fault Detection Features Description Temperature Proportional Fan Speed for Reduced The TC664/TC665 devices are PWM mode fan speed Acoustic Noise and Longer Fan Life controllers with FanSense technology for use with brushless DC fans. These devices implement temper- FanSense Protects against Fan Failure and ature proportional fan speed control which lowers Eliminates the Need for 3-wire Fans acoustic fan noise and increases fan life. The voltage Over Temperature Detection (TC665) at V (Pin 1) represents temperature and is typically IN Efficient PWM Fan Drive provided by an external thermistor or voltage output Provides RPM Data temperature sensor. The PWM output (V ) is OUT 2-Wire SMBus-Compatible Interface adjusted between 30% and 100%, based on the volt- age at V . The PWM duty cycle can also be pro- Supports Any Fan Voltage IN grammed via SMBus to allow fan speed control without Software Controlled Shutdown Mode forGree the need for an external thermistor. If V is not con- IN Systems nected, the TC664/TC665 will start driving the fan at a Supports Low Cost NTC/PTC Thermistors default duty cycle of 39.33%. See Section 4.3,Fan Space Saving 10-Pin MSOP Package Startu, for more details). Temperature Range: -40C to +85C In normal fan operation, a pulse train is present at the SENSE pin (Pin 8). The TC664/TC665 use these Applications pulses to calculate the fan revolutions per minute Personal Computers & Servers (RPM). The fan RPM data is used to detect a worn out, stalled, open or unconnected fan. An RPM level below LCD Projectors the user-programmable threshold causes the TC664/ Datacom & Telecom Equipment TC665 to assert a logic low alert signal (FAULT). The Fan Trays default threshold value is 500 RPM. Also, if this condi- File Servers tion occurs, FF (bit 0<0>) in the Status Register will also Workstations be set to a 1. General Purpose Fan Speed Control An over-temperature condition is indicated when the exceeds 2.6 V (typical). The TC664/ voltage at V IN Package Type TC665 devices indicate this by setting OTF(bit 5<X>) in the Status Register to a 1 . The TC665 device also 10-Pin MSOP line low during an over-temperature pulls the FAULT condition. V 1 10 V The TC664/TC665 devices are available in a 10-Pin IN DD MSOP package and consume 150 A during opera- C 9 V 2 F OUT tion. The devices can also enter a low-power shutdown TC664 mode (5 A, typ.) by setting the appropriate bit in the 8 SENSE SCLK 3 TC665 Configuration Register. The operating temperature range for these devices is -40C to +85C. SDA 4 7 NC 5 6 FAULT GND 2002-2013 Microchip Technology Inc. DS21737B-page 1TC664/TC665 Functional Block Diagram TC664/TC665 Note V OTF V V IN DD + OTF + Control + V Logic OUT Start-up FAULT Timer C F Missing Pulse V MIN Detect Clock Generator 50 k SENSE SCLK Serial Port 100 mV (typ.) Interface SDA NC GND Note: OTF condition applies for the TC665 device only. DS21737B-page 2 2002-2013 Microchip Technology Inc.