ON Semiconductor NCP803SN490T1 Supervisory Circuit

The NCP803SN490T1 is a high-performance supervisory circuit designed by ON Semiconductor to monitor power supply and system health in microprocessor and digital systems. This precision device is engineered to ensure that systems operate reliably by providing a reset signal to the microprocessor during power-up, power-down, or brown-out conditions. The NCP803SN490T1 is an essential component for any application that requires a high level of operational stability and security.

This supervisory circuit features a factory-trimmed reset threshold voltage of 4.90V, which makes it suitable for 5V-powered systems. It offers a tight reset threshold accuracy of ±1.5%, ensuring that the microprocessor is reset predictably and consistently whenever the supply voltage falls below the specified level. This high level of precision helps to prevent system errors and data corruption that can occur due to unexpected power supply fluctuations.

The NCP803SN490T1 comes in a compact SOT-23 package, making it an ideal choice for space-constrained applications. It boasts a low supply current of only 3µA (typical), contributing to overall power efficiency within the system. This feature is particularly beneficial for battery-powered devices where power consumption is a critical concern.

One of the key features of this supervisory circuit is its active-low, open-drain reset output. This configuration allows the NCP803SN490T1 to interface directly with a wide range of microprocessors and other digital ICs, providing a robust reset signal without the need for additional external components. The reset output remains asserted for a minimum of 140ms (typical) after VCC has risen above the reset threshold level, ensuring a proper system reset and start-up sequence.

Overall, the NCP803SN490T1 from ON Semiconductor is a reliable and efficient solution for system monitoring and reset functions. It is widely used in applications such as computers, embedded systems, storage systems, and other microprocessor-based applications where system integrity is paramount.

Key Features:

• Factory-trimmed V<sub>TH of 4.90V for 5V systems
• ±1.5% reset threshold accuracy
• Low supply current of 3µA (typical)
• Compact SOT-23 package
• Active-low, open-drain reset output
• Minimum 140ms reset pulse width