The RT9819B-28PU3 is a voltage detector, also known as a voltage supervisor or reset IC, manufactured by Richtek USA Inc. Its primary function is to monitor the supply voltage of electronic circuits and generate a reset signal when the voltage drops below a specific threshold. This helps to prevent erratic behavior and data corruption in microprocessors and other digital circuits due to low voltage conditions.

Applications

• Microprocessor and microcontroller systems
• Embedded systems
• Power supply monitoring
• Battery-powered equipment
• Industrial control systems

Features

• Accurate voltage detection
• Low supply current
• Open-drain output
• Fixed threshold voltage
• Small form factor

Benefits

• Ensures system stability by preventing erroneous operation during undervoltage conditions.
• Reduces the risk of data corruption in memory devices.
• Simplifies power supply monitoring circuitry.
• Extends battery life in portable devices.
• Conserves board space.

Additional Details

The RT9819B-28PU3 incorporates an internal precision voltage reference and a comparator. When the monitored voltage falls below the threshold (2.8V for this specific version), the open-drain output asserts low, indicating a reset condition. This low signal can be connected to the reset input of a microprocessor or microcontroller. Once the voltage recovers above the threshold, the output de-asserts (goes high) after a defined delay, allowing the system to resume operation. The open-drain output requires an external pull-up resistor to define the high-level voltage. Its low supply current makes it suitable for energy-sensitive applications. It is available in a compact package to minimize board space.