FAN CONTROLLER AND REMOTE TEMPERATURE SENSOR WITH SMBus SERIAL INTERFACE
SUNNYVALE, CA-November 3, 1999-Maxim Integrated Products introduces the MAX1669 fan controller with a precise digital thermometer that reports the temperature of a remote sensor. The remote sensor is a diode-connected transistor on the CPU die, ASIC, or low-cost, easily mounted diode.
The MAX1669 has an independent fan controller with a low current logic output requiring external power components to interface to a DC brushless fan. The fan controller has two operating modes: a low-frequency (20Hz to 160Hz) PWM mode intended for driving the fan motor, or a high-impedance DAC output that generates a variable linear DC control voltage. In PWM mode, the fan frequency can be synchronized to an external clock.
Other key features include general-purpose input/outputs (GPIO) for fan presence detection and a thermometer output intended as a fan override signal in case the host system loses the ability to communicate. The MAX1669 asserts an SMBus ALERT-bar interrupt if the measured temperature equals or exceeds the alarm threshold value. The OVERT-bar output is activated when the temperature equals or exceeds the critical temperature register's threshold.
The MAX1669 is available in a 16-pin QSOP package and is screened for the extended-industrial temperature range (-40°C to +85°C). Prices for the MAX1669 start from $3.20 (1000-up, FOB USA). A preassembled evaluation kit (MAX1669EVKIT) is available with recommended external components to reduce design time. | 
