The SP705CP is a supervisory circuit manufactured by Exar Corporation. It is designed to monitor voltage levels within electronic systems and provide a reset signal to microprocessors or microcontrollers when the voltage drops below a specified threshold. This functionality is crucial for ensuring that the system starts up correctly and prevents data corruption or other malfunctions that can occur due to low voltage conditions.

Applications

• Microprocessor-based systems
• Embedded systems
• Industrial control systems
• Automotive applications
• Consumer electronics

Features

• Precision voltage monitoring
• Power-on reset generation
• Low quiescent current
• Active-low reset output
• Watchdog timer (optional)
• Manual reset input (optional)

Benefits

• Protects systems from malfunctions due to undervoltage conditions
• Ensures reliable system startup
• Reduces the risk of data corruption
• Monitors program execution (with watchdog timer)
• Allows external reset (with manual reset input)
• Improves overall system reliability

Additional Details

The SP705CP monitors a specific voltage rail, typically 5V or 3.3V, and triggers a reset when the voltage falls below a pre-determined threshold. When power is initially applied, the reset output is asserted, holding the microprocessor in a reset state. Once the voltage rises above the threshold and remains stable for a specified delay period, the reset output is de-asserted, allowing the microprocessor to begin execution. The device may include a watchdog timer feature, which monitors the activity of the microprocessor. If the microprocessor fails to strobe the watchdog input within a specific timeout period, the SP705CP will assert a reset signal, preventing the system from becoming stuck in a loop or other error state. A manual reset input may also be included, allowing an external signal to trigger a system reset. The active-low reset output remains asserted (low) as long as the voltage is below the threshold, the watchdog timer has timed out, or the manual reset input is asserted. The low quiescent current makes the device suitable for battery-powered applications. The specific features and parameters of the SP705CP can vary depending on the specific configuration.