The **ADM1818-R23ART-RL** is a microprocessor supervisory circuit manufactured by Analog Devices. It is designed to monitor power supply voltages in microprocessor systems and provide a reset signal to the processor during power-up, power-down, and brownout conditions. --- ### ## Technical Specifications Below is a breakdown of the core electronic characteristics for this specific part number: | Parameter | Specification | | :--- | :--- | | **Threshold Voltage ($V_{TH}$)** | 2.31V (Nominal) | | **Reset Type** | Active-Low, Open-Drain | | **Reset Timeout Period** | 150 ms (Minimum) | | **Supply Voltage Range** | 1.0V to 5.5V | | **Operating Temperature** | -40°C to +85°C | | **Package Type** | SOT-23 (3-lead) | | **Supply Current** | 12 $\mu$A (Typical) | --- ### ### Key Functional Components #### 1. Voltage Comparator The device contains an internal high-precision voltage reference and a comparator. It continuously monitors the voltage at the $V_{CC}$ pin. If the voltage falls below the factory-set threshold (2.31V for the R23 variant), the reset output is triggered. #### 2. Power-On Reset (POR) To ensure the microprocessor starts in a known state, the ADM1818 maintains the reset signal for a specific duration (the "Timeout Period") after $V_{CC}$ rises above the threshold. This allows the system clock to stabilize. #### 3. Open-Drain Output The "Active-Low" output is **Open-Drain**, meaning it requires an external pull-up resistor to the desired logic voltage level. This feature allows for "wired-OR" connections where multiple reset sources can trigger the same reset line. #### 4. Manual Reset Input While the SOT-23 version is pin-constrained, the ADM1818 series generally supports manual reset capabilities by shorting the output pin to ground (depending on specific circuit implementation), as the device can sense external pulls. --- ### ### Part Number Breakdown (Decoding) The suffix of the part number provides specific information about its configuration: * **ADM1818**: Product Family (Low power supervisor). * **R23**: 2.31V Reset Threshold. * **ART**: Package Designator (SOT-23). * **RL**: Reel (Packaging format for automated assembly). --- ### ### Application Diagram (Simplified) ```text [Vcc 3.3V] | [Pull-up Resistor] | +----------+------[Reset Input of MCU] | | [Pin 1: Vcc] [Pin 2: /RESET] | | [ADM1818] | | | [Pin 3: GND]-----+------[GND] ```