Maxim Integrated MXD1818UR31+T Microprocessor Reset Circuit

The MXD1818UR31+T is a highly efficient microprocessor (µP) supervisory circuit designed by Maxim Integrated to monitor power supplies in digital systems. It provides a significant level of protection against low-voltage conditions, ensuring that the µP and its associated hardware operate correctly when power levels fall outside of the designated safe range.

This compact device is engineered to maintain system integrity by asserting a reset signal whenever the VCC supply voltage drops below the factory-set reset threshold level of 3.08V. The reset signal remains active for a minimum reset timeout period after VCC has risen above the reset threshold, providing a guaranteed reset duration of 140ms (min) at power-up, which allows the power supply and processor to stabilize before the system starts its operations.

The MXD1818UR31+T is available in a small, surface-mount SOT-323 package, making it an ideal choice for space-constrained applications. It operates over a wide temperature range of -40°C to +125°C, accommodating the demanding conditions of automotive and industrial environments. The device's low supply current of just 1.6µA (typical) makes it suitable for use in portable and battery-powered equipment where power efficiency is crucial.

Key features of the MXD1818UR31+T include:

• Factory-set reset threshold voltage: 3.08V
• Minimum reset timeout period: 140ms
• Low supply current: 1.6µA (typical)
• Wide operating temperature range: -40°C to +125°C
• Small SOT-323 package
• Immune to short VCC transients

The device is designed to be highly reliable, with immunity to short-duration VCC transients ensuring that the reset output will remain in the correct state during brief power glitches. This characteristic is particularly important in harsh electrical environments where power supply noise can lead to unintended system resets or erratic operation.

Overall, the MXD1818UR31+T from Maxim Integrated is a robust, low-power solution for µP system stability, offering precision monitoring of the power supply to safeguard digital systems against the consequences of undesirable voltage drops.