Maxim Integrated MAX809REXR Microprocessor Reset Circuit

The MAX809REXR is a compact, highly efficient microprocessor (µP) supervisory circuit designed by Maxim Integrated to monitor power supplies in digital systems. It provides a significant level of system reliability and accuracy required in critical electronic applications. This device is specifically engineered to keep microprocessor systems stable by monitoring the power supply voltage and asserting a reset signal whenever necessary.

Featuring a 3-pin transistor-to-transistor logic (TTL) compatible reset output, the MAX809REXR is capable of interfacing with a wide range of microprocessors and can assert a reset signal when the V<sub>CC supply voltage drops below the preset threshold level. The reset signal remains asserted for a minimum of 140ms after V<sub>CC has risen above the reset threshold level, ensuring that the system has adequate time to stabilize before the processor begins execution.

This device boasts a low supply current of 17µA (typical), making it an ideal solution for power-sensitive applications. The MAX809REXR operates over a wide voltage range and its threshold voltage is factory preset at 4.63V, suitable for monitoring 5V power supplies. The open-drain RESET output configuration of the MAX809REXR can pull the reset signal to ground, providing a robust low-level signal that is essential for reliable system reset.

The MAX809REXR comes in a compact SOT-323 package, which is optimized for space-constrained applications. Its small footprint and low power consumption make it an excellent choice for portable devices, computers, embedded systems, and other sophisticated electronic products that require a high level of power supply integrity.

With its precision monitoring capability and robust design, the MAX809REXR from Maxim Integrated is a crucial component for managing system integrity. It ensures that digital systems remain operational and stable, even in the event of power supply fluctuations or interruptions.

Key Features:

• Precision monitoring of 5V power supplies
• Low supply current of 17µA (typical)
• Factory preset threshold voltage: 4.63V
• Minimum 140ms reset signal assert time
• Compact SOT-323 package
• Open-drain RESET output
• Wide operating voltage range