Maxim Integrated MAX808MEPA+ Microprocessor Reset Circuit

The MAX808MEPA+ is a highly integrated microprocessor (µP) supervisory circuit designed by Maxim Integrated to monitor power supplies in µP and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used in systems with +5V powered µPs.

This compact device is engineered to provide a precise voltage threshold detector, which ensures that the µP is reset to a known state during power-up, power-down, and brownout conditions. The MAX808MEPA+ has an active-high reset signal output that remains asserted for a minimum of 140ms after VCC has risen above the reset voltage threshold. This feature guarantees that the system has sufficient time to stabilize before the processor starts its operation.

The reset threshold voltage for the MAX808MEPA+ is factory-set to a nominal value of 4.65V, which is suitable for +5V powered systems. Additionally, the device offers a debounced manual reset input, allowing for a manual reset of the connected µP. This input can be triggered with an external switch or logic signal, providing an extra layer of control for the system.

Encased in an 8-pin DIP package, the MAX808MEPA+ is designed for easy integration into a variety of digital systems. Its compact form factor makes it ideal for space-constrained applications, while its wide operating temperature range of -40°C to +85°C allows for deployment in diverse environmental conditions.

Key features of the MAX808MEPA+ include:

• Prescision VCC monitor for +5V power supplies
• 140ms min power-on reset pulse width
• Active-high RESET output
• Manual reset capability
• Immune to short VCC transients
• Low supply current of 40µA (typical)
• 8-pin DIP package suitable for through-hole mounting

With its robust design and reliable performance, the MAX808MEPA+ is an excellent choice for system designers looking to enhance the operational stability of their microprocessor-based systems.