F75389 is a system hardware monitoring and automatic fan speed controlling IC specific designed for graphic cards and PC etc.The F75389 can monitor several critical hardware parameters of the system, including voltages, temperatures and fan speeds which are very important for the system to work stably and properly. F75389 supports K and J type thermocouple sensor, PECI & AMD TSI for new generation CPU temperature reading usages. F75389 also supports new generational 45nm CPU temperature sensing by varied CPU β value.

An 11-bit analog-to-digital converter (ADC) was built inside F75389.The chip can monitor up to 4 analog voltage inputs, 2 fan tachometer inputs and3 temperature inputs (2 remote and 1 local sensor). The remote temperature sensorcan be performed by transistor 2N3906 and CPU/GPU thermal diode. The F75389can provide automatic fan speed control so that the system can operate at the minimum acoustic noise. This chip supports not only PWM duty mode (PWM) but also linear mode (DAC 0 ~ 3.3V) for fan speed control. The F75389 supports two fan control mechanisms: manual mode and auto mode where auto mode provides stage & linear mode. Internal oscillator was built in this chip and user can use the external clock input if users need the accurate fan speed count. Also the users can set up the upper and lower limits (alarm thresholds) of all monitored parameters andthe F75389can also issuewarning messages forthe system protection when there is something wrong with monitored items.

Through the BIOS or application software, the users can read all the monitored parameters of the system all the time. A pop-up warning can be also activated when the monitored item was out of the proper or pre-setting range. The F75389 is in the package of 16-pin SOP and powered by 3.3V.