## Overview of the ADM823MYRJZ-R7 The **ADM823MYRJZ-R7** is a high-performance supervisory circuit (microprocessor reset circuit) manufactured by **Analog Devices**. It is designed to monitor power supply voltage levels and code execution integrity in microprocessor-based systems. --- ### Core Specifications Below is a breakdown of the primary electrical characteristics of this specific variant: | Parameter | Specification | | :--- | :--- | | **Reset Threshold** | 4.38V (Nominal) | | **Supply Voltage (Vcc)** | 1.0V to 5.5V | | **Operating Current** | 5 µA (Typical) | | **Reset Timeout Period** | 140 ms (Minimum) | | **Output Type** | Push-Pull, Active-Low | | **Package / Case** | SOT-23-5 | | **Operating Temperature** | -40°C to +125°C | --- ### Key Functional Features The ADM823 series is known for combining several protective functions into a single small footprint: 1. **Precision Voltage Monitoring:** It generates a reset signal whenever the $V_{CC}$ supply voltage falls below the preset threshold (4.38V for the 'M' suffix). This prevents the processor from operating in an unstable voltage state. 2. **Watchdog Timer:** It includes a watchdog input (WDI). If the microprocessor fails to toggle this pin within a specific timeout period (typically 1.6 seconds), the device triggers a system reset. This is critical for recovering from software "hangs" or infinite loops. 3. **Manual Reset (MR) Input:** Allows for an external switch or logic signal to trigger a hardware reset regardless of voltage levels. 4. **Power-On Reset:** It ensures the reset signal remains active for at least 140ms after $V_{CC}$ rises above the threshold, allowing the system clock and power to stabilize. --- ### Pin Configuration (SOT-23-5) | Pin No. | Name | Description | | :--- | :--- | :--- | | 1 | **$\overline{RESET}$** | Active-low output; stays low during reset conditions. | | 2 | **GND** | Ground reference (0V). | | 3 | **$\overline{MR}$** | Manual Reset input (Active-low). | | 4 | **WDI** | Watchdog Input; must be toggled to prevent reset. | | 5 | **Vcc** | Supply voltage input/monitored voltage. | --- ### Application Example: Implementation Code In a typical microcontroller application (like Arduino or STM32), you must "kick" the watchdog regularly to prevent the ADM823 from resetting your board: ```cpp // Example C++ code for a microcontroller "kicking" the WDI pin #define WDI_PIN 5 void setup() { pinMode(WDI_PIN, OUTPUT); } void loop() { // Perform system tasks do_system_work(); // Toggle the Watchdog Input pin to signal the ADM823 that software is healthy digitalWrite(WDI_PIN, HIGH); delay(10); // Small pulse digitalWrite(WDI_PIN, LOW); // Ensure this loop completes faster than the 1.6s Watchdog Timeout } ```