## Overview of MN13822-R The **MN13822-R** is a CMOS-based voltage detection IC manufactured by Panasonic. It is primarily used for power-on reset and microcomputer system monitoring to prevent erratic operations during power supply fluctuations. --- ### 1. Key Technical Specifications The "R" suffix in the part number specifically identifies the detection voltage threshold. | Parameter | Specification | | :--- | :--- | | **Detection Voltage ($V_{DL}$)** | 4.0V to 4.3V (Typ. 4.2V) | | **Operating Voltage ($V_{DD}$)** | 1.5V to 6.0V | | **Current Consumption ($I_{SS}$)** | 1.0 $\mu$A (Very Low Power) | | **Output Type** | N-channel Open Drain | | **Package Type** | MINI-3P (Similar to SOT-23) | --- ### 2. Pin Configuration The device is housed in a small 3-pin package, making it ideal for space-constrained PCB designs. 1. **Pin 1 (OUT):** The reset output signal. Being an N-channel Open Drain, it requires a pull-up resistor to $V_{DD}$ or another logic level. 2. **Pin 2 (VDD):** Power supply input and voltage sensing pin. 3. **Pin 3 (VSS):** Ground connection. --- ### 3. Functional Mechanism The MN13822-R acts as a "watchdog" for the power supply. Its operation follows these logic phases: * **Low Voltage State:** If $V_{DD}$ is below the threshold (approx. 4.2V), the output (OUT) is pulled to **Low (VSS)**. This keeps the connected microcontroller in a Reset state. * **Transition:** Once $V_{DD}$ rises above the threshold, the output switches to **High-Impedance (Hi-Z)**, allowing the external pull-up resistor to pull the reset line to "High," releasing the microcontroller to start its program. * **Hysteresis:** The chip includes built-in hysteresis ($V_{HYS}$) to prevent "chatter" (rapid switching) if the power supply is noisy or rises slowly. --- ### 4. Typical Application Circuit Since this is an **Open Drain** output, a pull-up resistor is mandatory for the circuit to function. ```text VDD (Input Voltage) | +-------+-------+ | | | [VDD] [R_pullup] | | | | MN13822-R +------> To MCU RESET Pin | | [OUT]-----+ | [VSS] | GND ``` --- ### 5. Common Use Cases * **Microcomputer Reset:** Ensures the MCU only starts when the voltage is stable. * **Battery Life Monitoring:** Triggers a shutdown or warning when a battery drops below 4.2V. * **Memory Protection:** Disables Write-Enable pins on EEPROMs during power-down to prevent data corruption.