The NCT6686D is a member of Nuvoton’s eSIO series, combining the built-in microcontroller and the traditional legacy SIO functions. The NCT6686D supports an industrial standard External Flash based 1T 8-bit microcontroller, and 16 Kbyte SRAM.

The NCT6686D monitors several critical parameters in PC hardware, including power supply voltages, fan speeds and temperatures. Both high accuracy current mode and low cost thermistor temperature sensors are supported. The NCT6686D also supports the hardwired Smart Fan control system, including SMART FAN^TM I and SMART FAN^TM IV. Some hardware monitor peripherals are also supported, including SMBus master/slave, Intel® PECI and AMD® SB-TSI interface.

The NCT6686D supports traditional super IO functions, including LPC/eSPI interface, Printer Port, 2 UART, KBC, and GPI/O.

In addition, the NCT6686D implements some specific features that provide customers more benefits, such as power saving control function to further reduce the power consumption while the system is at S5 state, Consumer IR for remote control, Port 80 decode via LPC/eSPI interface for debug purpose, two-color LED to indicate the current power state.