The **MH22TAG-R** is a specific RFID (Radio Frequency Identification) electronic component, commonly used in automotive security systems, specifically as a **transponder key** for Mitsubishi vehicles. Below is a breakdown of its technical specifications and electronic functions. --- ## 1. Technical Overview The MH22TAG-R is an integrated circuit (IC) embedded within a key fob or tag. It acts as a passive transponder that communicates with the vehicle's immobilizer system to authorize engine ignition. | Feature | Specification | | :--- | :--- | | **Component Type** | RFID Transponder / Immobilizer Chip | | **Operating Frequency** | 125 kHz (Low Frequency) | | **Chip Architecture** | PCF7936 (Commonly compatible/equivalent) | | **Modulation** | ASK (Amplitude Shift Keying) or FSK (Frequency Shift Keying) | | **Communication** | Half-Duplex (HDX) / Full-Duplex (FDX) | | **Storage** | EEPROM for ID Code and Encryption Keys | --- ## 2. Key Electronic Components The internal structure of the MH22TAG-R consists of several critical sub-systems: ### A. The Antenna Coil * **Function:** This is a fine copper wire coil wrapped around a ferrite core. * **Purpose:** It picks up the electromagnetic field generated by the vehicle’s ignition barrel (exciter coil). It serves both as the power source (via induction) and the communication medium. ### B. Integrated Circuit (IC) * **Logic Unit:** Processes the challenge-response authentication sent by the car. * **EEPROM:** A non-volatile memory chip that stores the unique 40-bit or 128-bit identification code. * **Voltage Regulator:** Converts the induced AC current from the antenna into a stable DC voltage to power the internal logic. ### C. Capacitor * **Function:** Forms a resonant circuit with the antenna coil. * **Purpose:** It ensures the chip is tuned exactly to 125 kHz for maximum energy transfer efficiency. --- ## 3. Operational Logic The MH22TAG-R operates using **Passive RFID** technology, meaning it has no internal battery. 1. **Energy Harvesting:** When the key is inserted near the ignition, the car's exciter coil sends a 125 kHz pulse. The MH22TAG-R's antenna captures this energy. 2. **Authentication:** The vehicle sends a "Challenge" signal. The MH22TAG-R processes this using its internal encryption algorithm. 3. **Response:** The chip sends back a "Response" (the ID code). If the code matches the one stored in the car's ECU (Engine Control Unit), the immobilizer is disarmed, and the car starts. --- ## 4. Common Applications * **Vehicle Models:** Primarily used for Mitsubishi (e.g., Lancer, Outlander, ASX) and some PSA Group vehicles (Peugeot/Citroën) that share platforms. * **Key Type:** Used in non-proximity (blade) keys or as a backup emergency chip inside Smart Keys.