The SP809EK-L-3-1 is a voltage supervisor or voltage detector manufactured by Exar Corporation (now part of MaxLinear). This device monitors the voltage level of a power supply and provides a reset signal when the voltage falls below a certain threshold. It is typically used in microcontrollers and other digital systems to ensure proper startup and prevent data corruption during voltage dips.

Applications

• Microcontroller reset: Provides a reliable reset signal to microcontrollers during power-up or voltage drops.
• Voltage monitoring: Monitors the voltage level of a power supply and provides an alarm signal when the voltage falls outside of a specified range.
• Power-on reset (POR) circuits: Generates a reset signal at power-up to ensure proper system initialization.
• Battery monitoring: Monitors the voltage level of batteries in portable devices and provides a low-battery warning.
• Industrial control systems: Ensures proper operation of industrial equipment during voltage fluctuations.

Features

• Precision voltage monitoring: Accurately monitors the voltage level of a power supply.
• Adjustable reset threshold: Allows the user to set the voltage level at which the reset signal is asserted.
• Open-drain output: Provides a flexible interface for connecting to microcontrollers and other digital systems.
• Low supply current: Minimizes power consumption in battery-powered applications.
• Small package size: Allows for integration into small devices.

Benefits

• Reliable system startup: Ensures that the system starts up properly even during voltage fluctuations.
• Data protection: Prevents data corruption during voltage dips by resetting the system.
• Increased system reliability: Enhances the overall reliability of the system by monitoring and responding to voltage problems.
• Simplified design: Simplifies the design of power-on reset and voltage monitoring circuits.
• Cost-effective solution: Offers a balance of performance and price.

Additional Details

The SP809EK-L-3-1 operates by comparing the monitored voltage level to an internal reference voltage. When the monitored voltage falls below the reset threshold, the open-drain output is asserted (pulled low), signaling a reset condition. The reset signal remains asserted until the monitored voltage rises above the threshold plus a hysteresis voltage, preventing oscillations. The "L-3-1" suffix likely refers to specific voltage threshold levels. Pull-up resistors are usually required on the open-drain output to provide a high-level signal when the output is not asserted. External capacitors can also be used to adjust the reset timeout period.

Careful consideration should be given to the selection of the appropriate reset threshold voltage to ensure that the system is reset before data corruption occurs. The hysteresis voltage is also an important parameter to consider, as it determines the amount of voltage overshoot that is required to clear the reset condition.