Dual-Input Fan Controller IC Eyes NLX/ATX Supplies

Named MIC502 fan controller, this first member of a new family of thermal management ICs is designed to meet the needs of NLX and ATX power supplies, as well as those of PCs, file servers, telecomm and networking hardware, UPSs, and more. Among the features of the new IC are dual inputs, PWM fan drive, 4.5V to 13.2V supply range, high current (10 mA) output, over-temperature detection with fault output, automatic sleep mode, and integrated fan start-up timer.The chip's two control inputs can be used as thermistor- or voltage-control inputs, with the higher of the two used to set the duty cycle of the signal from the PWM output, which, in turn, offers sufficient drive to allow use of low-cost transistors to drive the fan. In addition, the IC can operate from the same 12V supply used by the fan and is designed for fully ratiometric temperature sensing, eliminating power supply drift as a source of error.