The **M93C66-RDS7** is a specific variant of the 4-Kbit serial MICROWIRE EEPROM (Electrically Erasable Programmable Memory) manufactured by **STMicroelectronics**. It is widely used for non-volatile data storage in consumer electronics and automotive applications. --- ## 1. Technical Specifications The "RDS7" suffix provides specific information regarding the voltage range, package type, and temperature grade. | Parameter | Specification | | :--- | :--- | | **Memory Size** | 4 Kbit (4096 bits) | | **Organization** | Configurable: 256 x 16-bit or 512 x 8-bit | | **Interface** | MICROWIRE (3-wire serial interface) | | **Operating Voltage** | 1.8V to 5.5V | | **Clock Frequency** | Up to 2 MHz | | **Package Type** | TSSOP8 (Thin Shrink Small Outline Package) | | **Temperature Range** | -40°C to +125°C (Automotive Grade 3) | | **Write Cycles** | 4 Million cycles (typical) | | **Data Retention** | 200 Years | --- ## 2. Pin Configuration (TSSOP8) The device typically uses an 8-pin layout to handle power and data communication. | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | **S** | Chip Select | | 2 | **C** | Serial Clock | | 3 | **D** | Serial Data Input | | 4 | **Q** | Serial Data Output | | 5 | **Vss** | Ground | | 6 | **ORG** | Internal Organization (x8 or x16) | | 7 | **DU** | Don't Use / No Connect | | 8 | **Vcc** | Supply Voltage | --- ## 3. Key Features ### Sequential Read The M93C66 allows for sequential reading of the entire memory map. Once a read command is initiated, the device continues to output data as long as the clock signal is provided. ### Write Protection To prevent accidental data loss, the device includes a "Write Disable" state upon power-up. A specific **WEN (Write Enable)** instruction must be sent before any data can be modified. ### Flexible Organization By tying the **ORG** pin to either $V_{cc}$ or $V_{ss}$, the user can choose how the memory is addressed: * **High (Vcc):** Organized as $256 \times 16$ bits. * **Low (Vss):** Organized as $512 \times 8$ bits. --- ## 4. Decoding the Part Number The suffix **RDS7** is broken down as follows: * **R**: Operating voltage of 1.8V to 5.5V. * **DS**: TSSOP8 package (8-lead, 3x4.4mm). * **7**: Device tested for Temperature Grade 3 (-40 to +125°C). ---