Microchip Technology Inc.’s MCP9802 digital temperature sensors converts temperatures between -55°C and +125°C to a digital word. They provide an accuracy of ±1°C (maximum) from -10°C to +85°C. The MCP9802 comes with user-programmable registers that provide flexibility for temperature sensing applications. The register settings allow user-selectable 9-bit to 12-bit temperature measurement resolution, configuration of the power-saving Shutdown and One-shot (single conversion on command while in Shutdown) modes and the specification of both temperature alert output and hysteresis limits. When the temperature changes beyond the specified limits, the MCP9802 outputs an alert signal. The user has the option of setting the alert output signal polarity as an active-low or active-high comparator output for thermostat operation, or as temperature event interrupt output for microprocessor-based systems. This sensor has an industry standard 2-wire, I2C/ SMBus compatible serial interface, allowing up to eight devices to be controlled in a single serial bus. These features make the MCP9802 ideal for sophisticated multi-zone temperature-monitoring applications.