### Technical Overview: HT2ICS2002W (HITAG 2 IC) The **HT2ICS2002W** is a high-performance silicon integrated circuit produced by NXP Semiconductors. It belongs to the **HITAG 2** family and is primarily used in contactless identification systems, specifically for animal tracking and industrial transponders. --- ### Key Specifications and Components | Parameter | Description | | :--- | :--- | | **Protocol** | ISO 11784 / 11785 Compliant | | **Frequency** | Low Frequency (LF) - 125 kHz | | **Memory Capacity** | 256 bits Total EEPROM | | **Modulation** | Manchester, Biphase, or PSK | | **Data Rate** | Up to 4 kbits/s | | **Operating Temp** | -40°C to +85°C | --- ### Electronic Architecture The internal structure of the HT2ICS2002W consists of several functional blocks that manage energy and data: #### 1. Analog Front End (AFE) * **Antenna Interface:** Connects directly to an external coil (L). Together with an internal capacitor, it forms a resonant circuit tuned to 125 kHz. * **Rectifier/Voltage Regulator:** Converts the incoming RF field into a DC supply voltage to power the chip. * **Clock Extraction:** Derives the system clock from the carrier frequency. #### 2. Digital Logic Control * **State Machine:** Manages the communication sequence, including anti-collision protocols and authentication. * **EEPROM Interface:** Handles the read/write operations to the non-volatile memory. #### 3. Security and Authentication * **Mutual Authentication:** The chip supports a 48-bit secret key. It uses a challenge-response mechanism to ensure that only authorized readers can access or change the data. * **Encrypted Data Transfer:** Data can be sent over the air in an encrypted format to prevent eavesdropping. --- ### Memory Map Breakdown The 256-bit EEPROM is organized into 8 blocks (32 bits per block): 1. **Block 0:** Configuration data and User ID. 2. **Block 1-2:** Password and Secret Keys. 3. **Block 3-7:** User Data (can be locked for read-only access). --- ### Typical Application Circuit The chip is designed to work with minimal external components, usually requiring only an inductor (coil) to function. ```text [ Reader Antenna ] <-- 125 kHz Field --> [ IC Antenna Terminals ] | | +---[ Coil ]----+ | (HT2ICS2002W)| +---------------+ ``` --- ### Common Use Cases * **Animal Identification:** Implantable glass transponders or ear tags. * **Industrial Logistics:** Tracking of reusable transport items (pallets, kegs). * **Access Control:** Key fobs or proximity cards for secure building entry.