The MAX809SEUR+T with Supervisor Integrated Circuit is a power on reset monitor (PoR) manufactured by Analog Devices. It is a small, low power, and highly integrated device that monitors the power supply voltage for reset detection purposes. It is used to detect when the power supply has gone outside of safe operating limits and to provide a reset on the microprocessor before any damage can occur. The device monitors the system's supply voltage and provides an output-active-low reset when it falls below the internal user-selectable reset threshold voltage. The threshold voltage can be set in the range of 1.2 V to 4.5 V with an accuracy of ±0.8% (max). The MAX809SEUR+T also has an internal watchdog timer with an adjustable timeout period from one to eight seconds, an adjustable reset pulse width, and an active-low reset output. The device has a built-in 1.8V low-dropout regulator to supply the 1.8V logic and control circuitry, and is packaged in a 6-pin SOT package.