The MIC809SU is a precision supervisory circuit manufactured by Micrel (now Microchip Technology). It is designed to monitor voltage levels in microprocessor (µP) and digital systems. Providing reliable reset signals, the MIC809SU ensures proper system start-up and prevents data corruption or erratic operation during power-up, power-down, or brownout conditions.

Applications:

• Microprocessor Systems: Used in embedded systems, industrial controllers, and consumer electronics to monitor the power supply voltage and initiate a reset when necessary.
• Digital Signal Processors (DSPs): Protects DSP-based systems from operating with insufficient voltage, ensuring accurate data processing.
• Battery-Powered Devices: Monitors battery voltage to prevent deep discharge and ensures reliable operation until the battery is fully depleted.
• Automotive Electronics: Incorporated into automotive control units to provide a safe reset during voltage fluctuations in the car's electrical system.
• Medical Devices: Ensures accurate and reliable operation of medical equipment by providing a reset signal in the event of a power anomaly.

Features:

• Precision Voltage Monitoring: Accurately monitors the input voltage to detect undervoltage conditions.
• Active-Low Reset Output: Provides an active-low reset signal that can be directly connected to the microprocessor's reset input.
• Fixed Reset Threshold: Features a predefined reset threshold voltage, which is factory-trimmed for accuracy.
• Guaranteed Reset Assertion: Asserts a reset signal during power-up, power-down, and brownout conditions.
• Low Supply Current: Minimizes power consumption, making it suitable for battery-powered applications.
• Small Package: Available in a small SOT-23 package, saving valuable board space.

Benefits:

• Improved System Reliability: Prevents erratic system behavior caused by low voltage conditions.
• Data Protection: Protects data from corruption during power failures or brownouts.
• Simplified System Design: Reduces the need for external components, simplifying the design process.
• Extended Battery Life: Low supply current contributes to longer battery life in portable devices.
• Cost-Effective: Offers a cost-effective solution for voltage monitoring and reset generation.

Additional Details:

The MIC809SU operates over a wide temperature range, typically -40°C to +85°C, making it suitable for industrial and automotive applications. Its supply voltage range usually extends from 1.6V to 5.5V, offering compatibility with various digital systems. The reset timeout period is pre-set and non-adjustable, ensuring consistent reset behavior. Different versions of the MIC809 family offer various reset threshold voltages to suit different application requirements. Always consult the datasheet for specific electrical characteristics and application guidelines.