The **ADM825TYKS-R7** is a high-performance supervisory circuit manufactured by Analog Devices. It is primarily designed to monitor power supply voltage levels and microprocessor activity, ensuring system stability by providing reset signals during power-up, power-down, or brownout conditions. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Reset Threshold** | 3.08V (Standard for 3.3V systems) | | **Output Type** | Push-Pull (Active Low) | | **Watchdog Timer** | 1.6 seconds (Typical) | | **Operating Voltage** | 1.0V to 5.5V | | **Supply Current** | 5 $\mu$A (Typical) | | **Package Type** | SC70-5 (Small Outline Transistor) | | **Temperature Range** | -40°C to +125°C | --- ### 2. Core Functional Parts The internal architecture of the ADM825 consists of several critical electronic blocks: #### A. Voltage Comparator & Reference This part continuously monitors the $V_{CC}$ pin against a highly accurate internal bandgap reference. If $V_{CC}$ drops below the **3.08V threshold**, the chip triggers a reset signal to prevent the microprocessor from executing corrupted instructions. #### B. Watchdog Timer (WDT) The watchdog is a safety mechanism. The microprocessor must "kick" or toggle the **WDI (Watchdog Input)** pin periodically. If the software freezes and fails to toggle this pin within **1.6 seconds**, the ADM825 issues a reset to reboot the system. #### C. Manual Reset (MR) Input This allows for a physical button or an external logic signal to force a system reset. It features an internal pull-up resistor and is "debounced," meaning it ignores tiny electrical noises caused by mechanical switches. #### D. Reset Generator Once the supply voltage rises above the threshold, this internal timer holds the **RESET** signal active for a minimum of **140ms**. This ensures the power supply has fully stabilized before the processor starts. --- ### 3. Pin Configuration ```markdown Pin 1: RESET - Active-low output signal. Pin 2: GND - Ground reference. Pin 3: MR - Manual Reset input. Pin 4: WDI - Watchdog Input (must be toggled by MCU). Pin 5: VCC - Supply voltage input (3.3V nominal). ``` --- ### 4. Typical Application Circuit When integrating this part into a PCB design, it is usually connected as follows: ```cpp // Logic Flow: 1. VCC (3.3V Rail) ----> [ADM825 Pin 5] 2. [ADM825 Pin 1] ----> Microprocessor RESET Pin 3. Microprocessor GPIO -> [ADM825 Pin 4] (Watchdog Clear) 4. Push Button --------> [ADM825 Pin 3] (Manual Reset) ```