The MAX809SEUR+T 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 reliability and precision, which is essential for maintaining the integrity of the system's operation. This device is particularly useful in applications where an accurate and automatic reset is critical for the µP and other logic systems upon power-up, power-down, or brown-out conditions.

One of the key features of the MAX809SEUR+T is its ability to assert a reset signal whenever the V<sub>CC supply voltage drops below a preset threshold, ensuring that the µP resets cleanly during power-up, power-down, and brown-out conditions. The reset output remains asserted for a period after V<sub>CC has risen above the reset threshold level, providing a guaranteed reset signal duration which can be critical for system recovery.

The device comes in a small, surface-mount SOT-23 package, making it ideal for space-constrained applications. It operates over a wide voltage range and features low supply current, making it suitable for battery-operated applications. Additionally, the MAX809SEUR+T is designed with an open-drain output, providing the flexibility to connect to a variety of logic levels.

Key specifications of the MAX809SEUR+T include:

• Precision monitoring of 3V, 3.3V, and 5V power supplies
• 140 ms min power-on reset pulse width
• Low supply current of 17 µA (typical)
• Wide operating temperature range
• Open-drain reset output

With its robust feature set, the MAX809SEUR+T is an excellent choice for use in microcontrollers, computers, embedded systems, and other electronics that require reliable monitoring of their power supply. Its easy integration and small footprint make it a versatile and indispensable component in maintaining system stability.