The **M3E18XQD-R** is a high-performance, industrial-grade memory module manufactured by **Innodisk**. It is specifically an **DDR3 1866MHz 8GB ECC VLP UDIMM**. Below is a detailed breakdown of its electronic components and specifications. --- ### 1. Key Technical Specifications The M3E18XQD-R is designed for server and embedded applications where space is limited and data integrity is critical. | Feature | Specification | | :--- | :--- | | **Memory Type** | DDR3 SDRAM | | **Form Factor** | VLP UDIMM (Very Low Profile Unbuffered DIMM) | | **Capacity** | 8 GB | | **Data Rate** | 1866 MT/s (PC3-14900) | | **Voltage** | 1.5V / 1.35V (Dual Voltage Support) | | **Error Correction** | ECC (Error Correction Code) | | **Pin Count** | 240-pin | | **Dimensions** | 133.35mm x 18.75mm (VLP height) | --- ### 2. Electronic Components Breakdown #### A. DRAM Chips (The Core Storage) * **Technology:** Uses high-density SDRAM chips (typically 512Mx8 or 1Gx8 configurations). * **Organization:** 1 Rank (1Rx8). * **Function:** These chips store the actual data. The "Q" in the part number often indicates the specific die revision or manufacturer of the DRAM cells. #### B. ECC (Error Correction Code) Logic * Unlike standard desktop RAM, this module includes an extra storage chip to handle parity bits. * **Electronic Function:** The ECC circuitry allows the system to detect and fix single-bit errors and detect multi-bit errors, preventing system crashes and data corruption. #### C. SPD EEPROM (Serial Presence Detect) * This is a small 8-pin chip located on the PCB. * **Function:** It stores the module's timing, voltage, and manufacturer information. When the system boots, the BIOS/UEFI reads this chip via the I2C bus to configure the memory controller correctly. #### D. VLP PCB Design * **Height:** The "VLP" stands for Very Low Profile. The PCB is only **18.75mm high**. * **Application:** This is electronically significant because it allows for better airflow in 1U rack servers and fits in compact blade servers where standard height RAM (30mm) would physically block components. --- ### 3. Environmental and Durability Features Innodisk designs the "M3" series for industrial environments: * **Gold Fingers:** 30μ” Gold Finger plating to ensure stable electrical connections in high-vibration or humid environments. * **Thermal Sensor:** Often includes a built-in thermal sensor to monitor heat levels and prevent thermal throttling. * **Anti-Sulfuration:** Many Innodisk modules feature a protective layer to prevent silver components from corroding in polluted environments. --- ### 4. Part Number Decoder | Part Segment | Meaning | | :--- | :--- | | **M3** | DDR3 Unbuffered DIMM | | **E** | ECC Functionality | | **18** | 1866 MHz Speed | | **X** | Capacity Identifier (8GB) | | **Q** | DRAM Die/Manufacturer Code | | **D** | Temperature Grade (Standard 0°C ~ 85°C) | | **-R** | Revision/Specific Feature Code |