## Overview of ADM823RYRJZ-R7 The **ADM823RYRJZ-R7** is a precision supervisory circuit manufactured by **Analog Devices**. It is designed to monitor power supply voltages in microprocessor-based systems. It provides a reset output during power-up, power-down, and brownout conditions, and includes a watchdog timer and manual reset input. --- ### Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Manufacturer** | Analog Devices | | **Function** | Supervisory Circuit (Reset & Watchdog) | | **Threshold Voltage ($V_{TH}$)** | 2.63V (Typical) | | **Supply Voltage Range** | 1.0V to 5.5V | | **Reset Timeout Period** | 140 ms (Minimum) | | **Watchdog Timeout** | 1.6 seconds (Typical) | | **Output Type** | Push-Pull, Active-Low ($\overline{RESET}$) | | **Package / Case** | SOT-23-5 | --- ### Core Functional Blocks The device integrates several critical electronic components into a single 5-pin SOT-23 package: 1. **Voltage Comparator:** Monitors the $V_{CC}$ pin against an internal fixed reference (2.63V for the 'R' variant). If $V_{CC}$ drops below this point, the reset triggers. 2. **Watchdog Timer (WDI Pin):** Requires the microprocessor to "kick" or toggle the WDI input within 1.6 seconds. If the software hangs and fails to toggle the pin, the chip issues a reset to reboot the system. 3. **Manual Reset ($\overline{MR}$):** A logic input that allows a physical button or external logic to trigger a reset pulse regardless of voltage levels or watchdog status. 4. **Reset Generator:** Ensures the reset signal stays active for at least 140ms after $V_{CC}$ rises above the threshold, ensuring the system clock stabilizes. --- ### Pin Configuration | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | $\overline{RESET}$ | Active-low output; stays low if $V_{CC} < V_{TH}$ or WDI times out. | | 2 | GND | Ground reference. | | 3 | $\overline{MR}$ | Manual Reset input (Active-low). | | 4 | WDI | Watchdog Input; must be toggled to prevent reset. | | 5 | $V_{CC}$ | Power supply and monitored voltage input. | --- ### Application Circuit Example Below is a conceptual representation of how the ADM823 connects to a Microcontroller (MCU): ```c // Typical Connection Logic [Power Rail 3.3V] ----> [VCC (Pin 5)] [Manual Switch] ----> [MR (Pin 3)] [MCU GPIO Out] ----> [WDI (Pin 4)] // Software must pulse this [MCU Reset In] <---- [RESET(Pin 1)] ```