## ADM1818-R22ART-RL: Electronic Component Overview The **ADM1818-R22ART-RL** is a precision voltage monitoring device manufactured by **Analog Devices**. It belongs to the microprocessor supervisory circuit family, designed to monitor power supply voltages in digital systems and provide a reset signal to processors during power-up, power-down, and brownout conditions. ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Reset Threshold** | 2.18V (Typical) | | **Output Type** | Open-Drain with Internal Pull-up (Active Low) | | **Supply Voltage (Vcc)** | 1.0V to 5.5V | | **Supply Current** | 12 $\mu$A (Typical) | | **Reset Timeout Period** | 150 ms (Minimum) | | **Operating Temperature** | -40°C to +85°C | | **Package Type** | SOT-23 (3-lead) | --- ### 2. Functional Description The primary purpose of this IC is to ensure that a microprocessor starts operating at a known state and remains stable. * **Voltage Monitoring:** It continuously monitors the $V_{CC}$ pin. If the voltage falls below the fixed threshold (2.18V for the R22 variant), the **RESET** output goes low. * **Power-on Reset (POR):** When power is first applied, the device keeps the RESET signal active for at least 150ms after $V_{CC}$ rises above the threshold. This allows the system clock to stabilize. * **Active Low / Open Drain:** The "R" in the part number indicates an active-low reset. The open-drain configuration with an internal pull-up resistor (typically 5.5 kΩ) allows for easy interfacing and wire-ORing with other reset sources. --- ### 3. Pin Configuration | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **RESET** | Active-low output. Remains low if Vcc is below threshold. | | 2 | **Vcc** | Supply voltage and monitored input. | | 3 | **GND** | Ground reference. | --- ### 4. Part Number Breakdown The suffixing follows a specific nomenclature used by Analog Devices: * **ADM1818**: Base model (Microprocessor Monitor). * **R22**: Indicates a **2.18V** reset threshold voltage. * **ART**: Refers to the **SOT-23** package type. * **RL**: Indicates **Tape and Reel** packaging for automated assembly. --- ### 5. Common Applications * Microprocessor and Microcontroller systems. * Intelligent Instruments. * Critical Computers/Controllers. * Portable and Battery-powered equipment. ---