The ASM809REUR from ON Semiconductor is a highly precise microprocessor (µP) supervisory circuit designed to monitor the power supplies in digital systems. It provides a significant function in ensuring that the microprocessor is reset to a known state during power-up, power-down, or brown-out conditions. The ASM809REUR helps to prevent code execution errors in microprocessors and microcontrollers by asserting a reset signal whenever the V<sub>CC supply voltage declines below a preset threshold, maintaining it until the V<sub>CC has stabilized above the threshold for a reliable period.

This device is particularly suitable for battery-powered applications due to its low power consumption. The reset timeout period, which is the minimum duration the reset signal is held active after V<sub>CC rises above the reset threshold, is factory-set to 140ms, ensuring a proper system reset. The ASM809REUR operates over a wide voltage range and is available in a compact SOT-23 package, making it ideal for space-constrained applications.

Key Features:

• Precision V<sub>CC monitoring of 3.08V, 3.3V, and 5V supplies
• Low supply current of 17µA (typical) suitable for battery-operated equipment
• Reset signal valid to V<sub>CC = 1V
• 140ms min reset pulse width
• Operating temperature range: -40°C to +85°C
• Compact SOT-23 package for space-saving

With its tight reset threshold accuracy and low power consumption, the ASM809REUR is an excellent choice for portable devices, computers, controllers, intelligent instruments, and critical µP and µC power monitoring. Its robustness is further complemented by the device's ability to handle ±10kV ESD pulses, providing additional protection for sensitive electronic components.

ON Semiconductor's commitment to quality ensures that the ASM809REUR microprocessor reset circuit is a reliable and efficient solution for maintaining system integrity across various applications. Its ease of integration into existing designs makes it a go-to component for engineers looking to enhance system stability and performance.