Maxim Integrated MAX809SUER Microprocessor Reset Circuit

The Maxim Integrated MAX809SUER is a compact, highly efficient microprocessor (µP) supervisory circuit designed to monitor power supplies in digital systems. It provides a crucial function by ensuring that the µP and its peripherals are reset properly during power-up, power-down, or brown-out conditions. The MAX809SUER helps in enhancing system reliability and preventing potential issues caused by improper initialization of the microprocessor when power levels fall outside of the acceptable range.

This device is particularly suitable for use in a wide range of applications, including computers, controllers, intelligent instruments, portable/battery-powered equipment, and other microprocessor-based systems. The MAX809SUER is engineered to assert a reset signal whenever the V<sub>CC supply voltage declines below the preset threshold, keeping it asserted for at least 140ms after V<sub>CC has risen above the reset threshold level. This feature ensures that the system has sufficient time to stabilize before the processor starts operating.

Key features of the MAX809SUER include:

• Integrated reset output: Active-low RESET output signal that remains asserted for a period after V<sub>CC has become stable, ensuring a reliable system reset.
• Precision monitoring: The device monitors the system voltage with high accuracy, with factory-trimmed reset threshold options available to match specific system requirements.
• Low power consumption: The MAX809SUER is optimized for low power consumption, making it ideal for portable and battery-powered applications.
• Compact SOT-23 packaging: The small size of the SOT-23 package allows for space-saving PCB design and is well-suited for space-constrained applications.

The MAX809SUER operates over a wide voltage range and temperature range, ensuring reliable performance under varying conditions. Its push-pull output stage eliminates the need for an external pull-up resistor, providing a direct interface to the microprocessor reset input. Additionally, the device’s immunity to short V<sub>CC transients is a testament to its robustness in unpredictable environments.

In summary, the Maxim Integrated MAX809SUER microprocessor reset circuit is a vital component for system stability, providing an essential safety net against power supply variability. Its precision voltage monitoring and low power consumption, combined with a compact form factor, make it an excellent choice for designers looking to enhance the reliability of their digital systems.