Maxim Integrated MAX6749KA29 Microprocessor Reset Circuit

The MAX6749KA29 from Maxim Integrated is a highly reliable and versatile microprocessor (µP) supervisory circuit designed to monitor power supplies in digital systems and provide a reset signal to the host processor when necessary. This compact device is essential for maintaining system integrity during power-up, power-down, and brown-out conditions.

Encased in a small SOT-23 package, the MAX6749KA29 is engineered to assert a reset signal whenever the VCC supply voltage falls below the factory-set reset threshold of 2.93V. The reset output remains asserted for a minimum reset timeout period after VCC has risen above the reset threshold, ensuring the system has adequate time to stabilize. The minimum reset timeout period for this device is 140ms, which provides a reliable window to prevent system errors during transient conditions.

The MAX6749KA29 features an active-low, push-pull reset output. This configuration allows for a direct connection to the reset pin of the microprocessor without the need for an external pull-up resistor, simplifying the design and reducing component count. The device's push-pull output stage ensures a solid connection to ground during reset, providing a robust signal to the connected µP.

One of the key advantages of this supervisor circuit is its low supply current of only 5.5µA (typical), making it an excellent choice for portable and battery-powered applications where power conservation is critical. The MAX6749KA29 operates over a wide supply voltage range from 1V to 5.5V, accommodating a variety of digital systems and applications.

Maxim Integrated has designed the MAX6749KA29 with the assurance of high reliability in mind. It incorporates a chip-enable input that can be used to manually trigger a reset, providing additional flexibility and control in system management. The device is also characterized for operation over the extended industrial temperature range of -40°C to +85°C, ensuring performance in harsh environments.

In summary, the MAX6749KA29 is a feature-rich, low-power, and highly reliable solution for microprocessor system reset applications. Its ease of integration, combined with Maxim Integrated's reputation for quality, makes it an ideal choice for designers looking to enhance system stability and reliability.