### Overview of ADM823MYKSZ-R7 The **ADM823MYKSZ-R7** is a high-performance supervisory circuit designed by Analog Devices. Its primary function is to monitor power supply voltage levels in microprocessor systems and provide a reset signal to ensure system integrity during power-up, power-down, or brownout conditions. --- ### Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Function** | Microprocessor Supervisory Circuit | | **Threshold Voltage ($V_{TH}$)** | 4.38V (Standard for 5V systems) | | **Supply Current** | 5 $\mu$A (Typical) | | **Reset Timeout Period** | 140 ms (Minimum) | | **Output Type** | Push-Pull, Active-Low ($\overline{RESET}$) | | **Package / Case** | SC-70-5 (5-lead) | | **Operating Temperature** | -40°C to +125°C | --- ### Core Functional Blocks The electronic architecture of the ADM823 consists of three main sub-systems: #### 1. Voltage Comparator and Reference The chip contains a high-precision internal voltage reference and a comparator. It continuously monitors the $V_{CC}$ pin. If the voltage drops below the factory-set threshold (4.38V for the 'M' variant), the device triggers a reset. #### 2. Watchdog Timer (WDT) This part includes an integrated watchdog input (**WDI**). * **Purpose:** It prevents system "hangs" or software freezes. * **Operation:** The microprocessor must toggle the WDI pin within a specific timeout period (typically 1.6 seconds). If the processor fails to strobe the pin, the ADM823 issues a reset. #### 3. Manual Reset (MR) Input The device features a debounced manual reset input. When the **$\overline{MR}$** pin is pulled low (e.g., via a physical push-button), it forces the $\overline{RESET}$ output to go active. --- ### Pin Configuration (SC-70) | Pin No. | Name | Description | | :--- | :--- | :--- | | 1 | **$\overline{RESET}$** | Active-low output; stays low during reset events. | | 2 | **GND** | Ground reference (0V). | | 3 | **$\overline{MR}$** | Manual Reset Input (Active-low). | | 4 | **WDI** | Watchdog Input; requires a transition to clear the timer. | | 5 | **$V_{CC}$** | Supply voltage and monitored input. | --- ### Typical Application Circuit ```c // Logic Representation of Reset Condition if (Vcc < Vth || MR == LOW || WDI_Time > 1.6s) { Reset_Output = LOW; // System Reset Triggered } else { Reset_Output = HIGH; // System Running Normally } ``` ---