The **MH25FAD-R** is an ultra-small, surface-mount (SMD) magnetic sensor based on the **Hall Effect** technology. It is primarily used in consumer electronics for non-contact switch applications. --- ## 1. Technical Specifications The following table summarizes the key electronic parameters of the MH25FAD-R: | Parameter | Value | Unit | | :--- | :--- | :--- | | **Supply Voltage (Vcc)** | 1.65 to 3.5 | V | | **Average Supply Current** | 1.5 to 3.0 | μA | | **Magnetic Type** | Omnipolar | - | | **Output Type** | Push-Pull | - | | **Package** | DFN1216-4 / SOT-543 | - | | **Operating Temperature** | -40 to +85 | °C | --- ## 2. Core Electronic Features ### A. Omnipolar Operation Unlike unipolar sensors that require a specific pole (North or South), the MH25FAD-R is **Omnipolar**. This means the sensor output will switch "Low" when it detects either a sufficiently strong North OR South pole. This simplifies assembly because the magnet orientation does not matter. ### B. Ultra-Low Power Consumption The "FAD" variant is designed for battery-operated devices. It uses a **clocked internal logic** system: 1. The device "wakes up" for a very short duration (microseconds) to sample the magnetic field. 2. It then enters a "sleep" mode for the remainder of the cycle. 3. This results in an average current draw of only a few microamps, extending battery life significantly. ### C. Push-Pull Output The output stage is a Push-Pull configuration. * **Benefit:** It does not require an external pull-up resistor (unlike Open-Drain sensors), which saves board space and further reduces power consumption. --- ## 3. Typical Pin Configuration | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **VDD** | Power Supply Input | | 2 | **OUT** | Digital Output (High/Low) | | 3 | **NC** | No Connection | | 4 | **GND** | Ground | --- ## 4. Common Applications Due to its tiny footprint and low power needs, it is commonly found in: * **Smartphones & Tablets:** Detecting flip-cover closure. * **Laptops:** Lid open/close sensing (Sleep mode trigger). * **Wearables:** Magnetic charging docking detection or button replacement. * **Smart Meters:** Detecting tampering via external magnets.