Maxim Integrated MAX809M Microprocessor Reset Circuit

The MAX809M from Maxim Integrated is a compact, highly efficient microprocessor (µP) supervisory circuit designed to monitor power supplies in µP and digital systems. It provides a significant level of protection by ensuring that the µP boots up in a known state every time the system is powered up. This device is particularly suited for portable and space-constrained applications owing to its small size and low power consumption.

Featuring a precision voltage sensor, the MAX809M constantly monitors the VCC for under-voltage conditions. On detecting an out-of-tolerance condition, the reset output is swiftly driven to its active state to signal the processor to reset. The reset output remains active for a preset timeout period after VCC has risen above the reset voltage threshold, thus ensuring the system has stabilized before the processor starts operating.

The MAX809M offers an array of features that make it an essential component for reliable system operation. These include:

• Precision Monitoring: With its precise factory-trimmed threshold voltages, the MAX809M ensures accurate monitoring of the power supply.
• Low Power Consumption: The device is designed for low power consumption, making it ideal for battery-operated equipment.
• Manual Reset Input: It includes a manual reset input that allows for a reset to be triggered with an external switch or logic signal, providing additional system control.
• Reset Timeout: A fixed reset timeout delay maintains the reset output in the active state for a specified duration after the supply voltage has become valid to allow the system to stabilize.
• Compact Packaging: Available in a small SOT23 package, the MAX809M saves on board space and is convenient for use in tight designs.

The MAX809M is an ideal solution for managing system integrity through power monitoring and is commonly used in applications such as computers, controllers, intelligent instruments, critical µP and µC power monitoring, and portable/battery-powered equipment. With its robust feature set, the MAX809M ensures that digital systems operate reliably and consistently, safeguarding against the potential pitfalls of power supply fluctuations and system instability.