The ADM1030 is an ACPI-compliant two-channel digital thermometer and under/over temperature alarm, for use in computers and thermal management systems. Optimized for the Pentium III, the higher 1C accuracy offered allows systems designers to safely reduce temperature guardbanding and increase system performance. A Pulsewidth Modulated (PWM) Fan Control output controls the speed of a cooling fan by varying output duty cycle. Duty cycle values between 33%100% allow smooth control of the fan. The speed of the fan can be monitored via a TACH input for a fan with a tach output. The TACH input can be programmed as an analog input, allowing the speed of a 2-wire fan to be determined via a sense resistor. The device will also detect a stalled fan. A dedicated Fan Speed Control Loop provides control even without the intervention of CPU software. It also ensures that if the CPU or system locks up, the fan can still be controlled based on temperature measurements, and the fan speed adjusted to correct any changes in system temperature. Fan Speed may also be controlled using existing ACPI software. One input (two pins) is dedicated to a remote temperaturesensing diode with an accuracy of 1C, and a local temperature sensor allows ambient temperature to be monitored. The device has a programmable INT output to indicate error conditions. There is a dedicated FAN_FAULT output to signal fan failure. The THERM pin is a fail-safe output for over-temperature conditions that can be used to throttle a CPU clock.