Maxim Integrated MAX809LEUR+T Microprocessor Reset Circuit

The MAX809LEUR+T is a compact, highly efficient microprocessor (µP) supervisory circuit designed to monitor power supplies in digital systems. Manufactured by Maxim Integrated, this device provides excellent circuit reliability and low-cost system housekeeping for applications such as computers, controllers, and intelligent instruments.

This supervisory circuit is designed to assert a reset signal whenever the VCC supply voltage declines below a preset threshold, ensuring that the µP and its peripherals are reset properly during power-up, power-down, and brown-out conditions. The reset signal remains asserted for a minimum of 140ms after VCC has risen above the reset voltage threshold, providing ample time for the system to stabilize.

The MAX809LEUR+T is characterized by its precision factory-set reset voltage thresholds suited for 3V, 3.3V, and 5V powered circuits. Its low supply current of 17µA (typical) makes it an energy-efficient choice for portable and battery-operated applications. The device's open-drain RESET output can sink currents up to 5.5V, allowing for a versatile connection to different logic levels.

Available in a compact SOT-23 package, the MAX809LEUR+T is designed for surface mount technology (SMT), making it convenient for high-density PCB designs. Its temperature range of -40°C to +105°C ensures reliable operation in a wide range of environmental conditions.

Key features of the MAX809LEUR+T include:

• Guaranteed RESET output in VCC down to 1.0V
• Factory-set reset thresholds suitable for 3V, 3.3V, and 5V supplies
• Low 17µA supply current
• Minimum 140ms reset pulse width
• Immunity to short VCC transients
• Open-drain RESET output
• Compact SOT-23 packaging

The MAX809LEUR+T is an ideal solution for systems that require a reliable reset mechanism to maintain proper operation and protect against data corruption during abnormal supply conditions. Its ease of integration and robust feature set make it a popular choice among designers looking to enhance system reliability with minimal additional complexity.