The SP691AEN-TR is a supervisory circuit manufactured by Exar Corporation. It is designed to monitor voltage levels in digital systems and provide a reset signal to microprocessors or microcontrollers when the voltage falls below a certain threshold. This ensures that the system starts up in a known state and prevents data corruption or erratic behavior due to low voltage conditions.

Applications

• Microprocessor and microcontroller systems
• Embedded systems
• Industrial control systems
• Automotive electronics
• Portable electronic devices

Features

• Precision voltage monitoring
• Power-on reset generation
• Low quiescent current
• Active-low reset output
• Immune to short negative transients
• Small package options

Benefits

• Prevents system malfunction due to low voltage
• Ensures reliable system startup
• Reduces the risk of data corruption
• Simplifies system design
• Improves system stability
• Extends battery life in portable applications

Additional Details

The SP691AEN-TR typically monitors a 5V power supply and has a reset threshold voltage of around 4.65V. When the supply voltage drops below this threshold, the reset output is asserted, holding the microprocessor in a reset state. Once the voltage rises above the threshold, the reset output is de-asserted after a specified delay, allowing the microprocessor to begin normal operation. The device features a low quiescent current, which makes it suitable for battery-powered applications. The exact reset delay time is factory trimmed, providing more accuracy. Furthermore, the SP691AEN-TR is designed to be immune to short negative transients on the power supply line, preventing false reset signals. It is offered in a variety of packages, including surface-mount packages, to suit different application requirements.