The LM809LD-2.63 is a high-quality microprocessor supervisory circuit from Texas Instruments, designed to monitor the power supplies in microprocessor systems and digital systems. It offers precision monitoring of 3.3V, 5V, and adjustable power supply systems, ensuring system reliability during power failures or significant changes in voltage supply. The LM809LD-2.63 has a reset output during power-up, power-down, and brown-out conditions, and comes with a reset threshold level of 2.63V. It also features a low supply current of 17µA (typical) and is available in the 5-pin SOT-23 package. The LM809LD-2.63 has a guaranteed reset output valid for VCC down to 1V and is characterized for operation over a temperature range of -40°C to 85°C.