## Overview of the ADM823TYKS-R7 The **ADM823TYKS-R7** is a high-performance supervisory circuit designed by Analog Devices. It is primarily used to monitor power supply voltages in microprocessor systems and provides a reset signal during power-up, power-down, and brownout conditions. ### Key Specifications | Feature | Specification | | :--- | :--- | | **Reset Threshold** | 3.08V (Typical) | | **Output Type** | Push-Pull, Active Low | | **Watchdog Timer** | 1.6 seconds (Typical) | | **Reset Timeout** | 200 ms (Typical) | | **Manual Reset** | Yes (Manual Reset Input) | | **Supply Current** | 7 µA (Very Low Power) | | **Package** | SC70-5 (Small Outline Transistor) | --- ### Core Functions The ADM823 series combines several critical functions into a single miniature package to ensure system stability: 1. **Power-On Reset (POR):** Asserts a reset signal whenever the $V_{CC}$ supply voltage falls below the preset threshold (3.08V for the 'T' variant). It keeps the reset active for at least 140ms after $V_{CC}$ rises above the threshold. 2. **Watchdog Timer:** The chip monitors the microprocessor's activity. If the processor fails to "pet the dog" (toggle the WDI pin) within 1.6 seconds, the ADM823 triggers a reset. This prevents the system from staying in a "hung" or "frozen" state. 3. **Manual Reset (MR) Input:** Allows a physical button or external logic to trigger a system reset independently of the voltage level or watchdog timer. --- ### Pin Configuration (SC70-5) | Pin No. | Name | Function | | :--- | :--- | :--- | | 1 | **$\overline{RESET}$** | Active-low output that triggers the CPU reset. | | 2 | **GND** | Ground reference. | | 3 | **$\overline{MR}$** | Manual Reset input (Active Low). | | 4 | **WDI** | Watchdog Input. Must be toggled to prevent reset. | | 5 | **$V_{CC}$** | Supply voltage / Monitored voltage. | --- ### Application Example In a typical embedded system, the ADM823 is connected as follows: ```c // Pseudo-code for servicing the Watchdog Timer while(true) { Perform_System_Tasks(); // Toggle the WDI pin to prevent ADM823 from resetting the CPU GPIO_Write(WDI_PIN, HIGH); Delay_Microseconds(1); GPIO_Write(WDI_PIN, LOW); } ``` ---