## Overview of the 11AA02UID The **11AA02UID** is a specialized Serial Electrically Erasable Programmable Read-Only Memory (EEPROM) developed by Microchip Technology. It belongs to the UNI/O® family, which is known for its single-pin interface capability. This specific part is unique because it comes pre-programmed with a **32-bit unique ID** and a **48-bit or 64-bit EUI (Extended Unique Identifier)**, making it ideal for networking and identification applications. --- ### Technical Specifications | Feature | Specification | | :--- | :--- | | **Memory Size** | 2 Kbits (256 x 8 bits) | | **Interface** | UNI/O® Serial Interface (Single I/O) | | **Operating Voltage** | 1.8V to 5.5V | | **Operating Current** | 1 mA (Read), 3 mA (Write) | | **Frequency** | 10 kHz to 100 kHz | | **Endurance** | 1,000,000 erase/write cycles | | **Data Retention** | > 200 years | | **Package Options** | SOT-23, SOIC, TDFN | --- ### Key Electronic Components & Features #### 1. The UNI/O® Bus Unlike I2C (2 wires) or SPI (3-4 wires), the 11AA02UID uses a **Single-Wire Interface**. * **SCIO (Serial Clock/Data Input/Output):** This single pin handles both clock synchronization and bidirectional data transfer. * **Advantage:** Reduces the number of I/O pins required on the microcontroller, simplifying PCB routing and allowing for smaller connectors. #### 2. Pre-programmed EUI Node Identity The "UID" suffix indicates that the chip is factory-programmed with a globally unique address. * **MAC Address Compatibility:** It can be used as a MAC address for Ethernet, Wi-Fi, or Bluetooth devices. * **Read-Only Protection:** The section of memory containing the unique ID is write-protected to prevent accidental overwriting. #### 3. Internal Logic and Timing * **Manchester Encoding:** The data is sent using Manchester encoding, which embeds the clock within the data stream, ensuring the receiver stays synchronized. * **Status Register:** Includes a WIP (Write In Progress) bit and block protection bits to manage memory security and operations. --- ### Pin Configuration (SOT-23 Example) | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **SCIO** | Serial Clock and Data I/O | | 2 | **Vss** | Ground | | 3 | **Vcc** | Power Supply | --- ### Typical Application Circuit In a basic electronic circuit, the 11AA02UID requires minimal external components. ```text Microcontroller 11AA02UID +---------------+ +-----------+ | | | | | GPIO <--------> SCIO (1) | | | | | | +---------------+ R | Vss (2) | | +-----+-----+ Vcc (3) | GND ``` *Note: A pull-up resistor (typically 10kΩ to 47kΩ) is required on the SCIO line because the output is open-drain.*