onsemi MAX809SN293D2T1G: Ultra-Low-Power μP Supervisory Reset Circuit

In the realm of embedded systems and portable electronics, ensuring a controlled and reliable startup or recovery from power faults is paramount. The onsemi MAX809SN293D2T1G stands as a critical component in achieving this, serving as an ultra-low-power microprocessor (μP) supervisory reset circuit. This device is engineered to monitor system power supply voltages and provide a reset signal to the host microprocessor, ensuring it operates only within valid voltage ranges, thereby preventing erratic behavior and data corruption.

The core function of the MAX809SN293D2T1G is to assert a reset signal whenever the supply voltage (VCC) drops below a predefined factory-set threshold. This specific variant is preset to a 2.93V threshold, making it ideal for monitoring 3V and 3.3V power supplies commonly found in modern low-voltage logic systems. Once VCC falls beneath this trip point, the active-low RESET output is asserted. It remains asserted until VCC rises above the threshold and remains stable for a minimum of 140ms (typical), a crucial delay that allows the power supply and microprocessor oscillator to stabilize fully.

A defining characteristic of this supervisory IC is its exceptionally low supply current, typically drawing just 7.5µA. This ultra-low quiescent current is a vital feature for battery-powered applications—such as IoT sensors, medical devices, and handheld instruments—where every microamp of current consumption directly impacts battery life. The device ensures system reliability without becoming a significant drain on the power source itself.

Housed in a space-saving SOT-23-3 package, the MAX809SN293D2T1G offers a compact and robust solution for board designs where physical space is at a premium. Its simplicity, requiring only a single bypass capacitor on VCC for stability, makes it incredibly easy to implement into new or existing designs, reducing both design time and component count.

ICGOODFIND: The onsemi MAX809SN293D2T1G is an exemplary solution for designers prioritizing system reliability and power efficiency. Its combination of a precise factory-set voltage threshold, ultra-low power consumption, and a compact form factor makes it an indispensable component for ensuring data integrity and controlled operation in a vast array of low-voltage, power-sensitive electronic products.

Keywords: Ultra-Low-Power, Microprocessor Supervisor, Reset Circuit, Voltage Monitoring, Battery-Powered Applications.