STMicroelectronics STM809SWX6F Microprocessor Reset Circuit, SOT-23-3

The STMicroelectronics STM809SWX6F is a low-power supervisory circuit designed to monitor the power supply of a microprocessor. It performs the critical task of asserting a reset signal whenever the VCC supply voltage dips below a preset threshold, ensuring system stability and preventing malfunctions during power anomalies.

This device features an active-low, push-pull output and is engineered to maintain the reset assertion until the supply voltage has stabilised above the threshold for a specified minimum period. It is designed for high reliability, with a guaranteed reset assertion even when VCC drops as low as 1V. The circuit draws minimal current, making it suitable for power-sensitive applications.

Key Features & Benefits

• Reliable Power Monitoring: Continuously monitors a single voltage rail, triggering a reset during undervoltage conditions to protect your microprocessor.
• Wide Operating Range: Functions with a supply voltage from 1.2V to 5.5V, offering flexibility for various digital logic levels.
• Low Power Consumption: A typical supply current of just 6µA minimises the impact on overall system power budgets.
• Robust Reset Pulse: Generates a minimum reset pulse width of 140ms, ensuring the connected microprocessor has adequate time to initialise properly.
• Compact Surface Mount Package: Housed in a space-saving SOT-23-3 package, ideal for modern, compact PCB designs.
• Industrial Temperature Range: Operates reliably in environments from -40°C to 85°C, supporting industrial-grade applications.

With its precise 2.93V threshold and integrated delay timer, the STM809SWX6F provides a simple yet effective solution for enhancing system reliability and preventing erratic behaviour in digital circuits during power-up, power-down, and brownout events.