19-2225; Rev 0; 10/01
Remote-Junction Temperature-Controlled Fan-Speed Regulator with SMBus Interface
General Descripti...
19-2225; Rev 0; 10/01
Remote-Junction Temperature-Controlled Fan-Speed
Regulator with SMBus Interface
General Description
The MAX6660 is a remote temperature sensor and fanspeed
regulator that provides a complete fan-control solution. The remote temperature sensor is typically a common-collector
PNP, such as a substrate
PNP of a microprocessor, or a diode-connected
transistor, typically a low-cost, easily mounted 2N3904
NPN type or 2N3906
PNP type. The device also incorporates a closed-loop fan controller that regulates fan speed with tachometer feedback. The MAX6660 compares temperature data to a fan threshold temperature and gain setting, both programmed over the SMBus™ by the user. The result is automatic fan control that is proportional to the remotejunction temperature. The temperature feedback loop can be broken at any time for system control over the speed of the fan. Fan speed is voltage controlled as opposed to PWM controlled, greatly reducing acoustic noise and maximizing fan reliability. An on-chip power device drives fans rated up to 250mA. Temperature data is updated every 0.25s and is readable at any time over the SMBus interface. The MAX6660 is accurate to 1°C (max) when the remote junction is between +60°C to +100°C. Data is formatted as a 10-bit + sign word with 0.125°C resolution. The MAX6660 is specified for -40°C to +125°C and is available in a 16-pin QSOP package.
Features
o Integrated Thermal Sensing and Fan-Regulation Solution o Programmable Fan Thres...