Maxim Integrated MAX709CPA Microprocessor Supervisory Circuit

The MAX709CPA is a highly reliable microprocessor (µP) supervisory circuit designed to monitor power supplies in µP and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered circuits.

This supervisory circuit from Maxim Integrated ensures that the µP is reset to a known state during power-up, power-down, or brown-out conditions. It achieves this through its key features which include a reset output during power-up, power-down, and brown-out conditions, a reset pulse width of 200ms minimum, and a debounced manual reset input.

The MAX709CPA comes in a compact 8-pin DIP package, making it suitable for space-constrained applications. Its operating temperature range extends from 0°C to +70°C, ensuring reliable performance across a wide range of environmental conditions. The device also offers a low supply current of 17µA, which is particularly beneficial for battery-operated equipment.

One of the significant advantages of the MAX709CPA is its ability to monitor 5V power supplies with a 4.65V threshold, ensuring that the µP is held in reset until the supply voltage reaches the stable operating level. Additionally, its active-low RESET output remains asserted for a minimum of 200ms after VCC has risen above the reset threshold level, providing ample time for the system to stabilize.

The MAX709CPA's manual reset capability allows the user to initiate a reset with an external pushbutton, providing an additional layer of control. This feature is especially useful for service or debugging purposes, allowing for a system reset without the need to cycle power.

In summary, the Maxim Integrated MAX709CPA supervisory circuit is an essential component for ensuring the reliable operation of µP systems. Its combination of features, including power monitoring, manual reset, and minimum external components, makes it an ideal choice for designers looking to improve system integrity with minimal complexity.

Key Features:

• Reset Output During Power-up, Power-down, and Brown-out Conditions
• Minimum Reset Pulse Width of 200ms
• Debounced Manual Reset Input
• Compact 8-Pin DIP Package
• Low Supply Current of 17µA
• Monitors 5V Power Supplies with 4.65V Threshold