The **MH28TAD-R** is an electronic component primarily classified as a **Magnetic Sensor** (specifically a Hall Effect Switch). It is designed to detect the presence of a magnetic field and convert that physical presence into a digital electrical signal. --- ### 1. General Specifications The following table highlights the core technical characteristics of the MH28TAD-R: | Parameter | Specification | Unit | | :--- | :--- | :--- | | **Component Type** | Hall Effect Sensor IC | - | | **Output Type** | CMOS / Digital | - | | **Operating Voltage** | 1.8V to 5.5V | V | | **Supply Current** | ~2.0 - 5.0 (Low Power) | µA | | **Sensitivity** | High | Gauss | | **Package Type** | SOT-23 / TO-92S | - | | **Magnetic Polarity** | Omni-polar (Detects N and S) | - | --- ### 2. Key Features * **Omni-polar Detection:** Unlike unipolar sensors that require a specific side of a magnet, this part activates regardless of whether the North or South pole is facing the sensor. * **Micropower Operation:** This is a "low-power" device, making it ideal for battery-operated electronics. It often uses a "clocking" mechanism to sleep between measurements. * **Internal Stabilization:** Includes an on-chip Hall voltage generator, small-signal amplifier, and a chopper-stabilized stage to reduce offset voltage and temperature drift. * **Solid State:** No moving parts, ensuring a much longer lifespan compared to mechanical reed switches. --- ### 3. Pin Configuration (SOT-23) Typical pinout for the SMD version: | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **VDD** | Power Supply Input | | 2 | **OUT** | Digital Output (High/Low) | | 3 | **GND** | Ground | --- ### 4. Common Applications Due to its small size and low power consumption, the MH28TAD-R is found in: 1. **Laptops/Tablets:** To detect when the lid is closed (Sleep mode). 2. **Smart Water Meters:** For non-contact pulse counting. 3. **Handheld Devices:** Proximity sensing in flip phones or cases. 4. **Security Systems:** Window and door open/close sensors.