The ADM1028 is a low-cost temperature monitor and fan controller for microprocessor-based systems. The temperature of a remote sensor diode may be measured, allowing monitoring of processor temperature in single processor systems. An on-chip temperature sensor monitors ambient system temperature. Measured values can be read out via the System Management Bus, and values for limit comparisons can be programmed in over the same serial bus. The ADM1028 also contains a DAC for fan speed control. An automatic hardware temperature trip point is provided and the fan will be driven to full speed if it is exceeded. Finally, the chip has remote reset and power-down functionality, allowing it to be remotely shut down via the SMBus. The ADM1028's 3.0 V to 5.5 V supply voltage range, low supply current, and SMBus make it ideal for a wide range of applications. These include hardware monitoring applications in PCs, electronic test equipment, and office electronics.