ON Semiconductor MAX809LTR Microprocessor Reset Circuit

The ON Semiconductor MAX809LTR is a compact, three-pin, microprocessor (µP) supervisory circuit designed to monitor power supplies in digital systems. It provides a significant level of system reliability and accuracy required by modern electronics. This device is particularly well-suited for use in microprocessor-based systems where it can provide a reliable reset signal to the µP during power-up, power-down, or brown-out conditions.

The MAX809LTR operates by monitoring the VCC voltage. When the VCC supply voltage falls below the preset threshold level, the reset output is asserted (driven low) to reset the connected microprocessor. The reset signal remains active for a period of time after VCC has risen above the reset threshold level, ensuring the system has sufficient time to stabilize before the processor begins operation. This timeout period, known as the reset timeout period, is typically 140ms, providing a suitable delay for most microprocessor systems.

Key features of the MAX809LTR include:

• Precision monitoring of 3V, 3.3V, and 5V supply voltages
• Low supply current of 17µA (typical), which is ideal for power-sensitive applications
• No external components required, simplifying design and reducing board space
• Guaranteed RESET output valid to VCC = 1V, ensuring reliable operation during low voltage conditions
• Available in a compact SOT-23 package, making it suitable for space-constrained applications

The MAX809LTR is commonly used in applications such as computers, controllers, intelligent instruments, portable/battery-powered products, and other microprocessor-based systems that require a precise and reliable reset function.

ON Semiconductor's commitment to quality ensures that the MAX809LTR is a reliable component for maintaining system integrity. Its ease of integration and minimal power consumption make it an excellent choice for designers looking to enhance system stability without compromising on performance or power efficiency.

Whether you are working on a new design or updating an existing system, the ON Semiconductor MAX809LTR provides a simple and effective solution for your microprocessor reset needs, ensuring your systems operate reliably and consistently.