MAX708R Microprocessor Supervisory Circuit

The MAX708R 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 to ensure that the system operates reliably by offering functions such as reset output during power-up, power-down, and brownout conditions.

One of the key features of the MAX708R is its ability to assert a reset signal whenever the VCC supply voltage falls below a preset threshold, ensuring that the µP resets cleanly during power-up, power-down, and brownout occurrences. The reset output remains asserted for a minimum of 140ms after VCC rises above the reset threshold, providing ample time for the system to stabilize.

The device is highly versatile, with a reset threshold voltage factory set at 4.65V, suitable for 5V-powered circuits. Additionally, the MAX708R comes with a manual reset feature, allowing for a reset to be triggered with an external switch, which is an essential feature for systems requiring user-initiated resets.

For enhanced system reliability, the MAX708R also includes a watchdog timer that forces the reset signal to go active if the watchdog input has not been toggled within a preset timeout period. This feature ensures that the system will recover from a software lock-up or other fault conditions.

Designed for low power consumption, the MAX708R draws a quiescent current of only 17µA, making it an excellent choice for power-sensitive applications. It is available in a variety of packages, including the 8-pin SO and 8-pin µMAX packages, providing flexibility in terms of space constraints on the PCB.

Overall, the MAX708R is an ideal solution for system designers looking for a simple, cost-effective way to enhance the operational stability and reliability of their microprocessor-based systems. Its integration of multiple supervisory features into a single chip makes it a compact and practical choice for a wide range of applications.