The **M400320B2PJ-R** is a specific part number typically associated with high-performance **DDR4 SDRAM modules**, often manufactured by Samsung (or related partners) for server and enterprise environments. Below is a breakdown of its electronic components, specifications, and architecture. --- ## 1. Core Technical Specifications This module is a **VLP (Very Low Profile) RDIMM**, designed for high-density computing where vertical space is limited. | Parameter | Specification | | :--- | :--- | | **Memory Type** | DDR4 SDRAM | | **Form Factor** | 288-pin RDIMM (Registered DIMM) | | **Capacity** | 32GB | | **Speed** | 2400 MT/s (PC4-19200) | | **Voltage** | 1.2V (Standard DDR4 Low Voltage) | | **Rank** | 2Rx4 (Dual Rank, x4 Organization) | | **CAS Latency** | CL17 | --- ## 2. Key Electronic Components ### A. DRAM Integrated Circuits (ICs) The module uses multiple DRAM chips (typically 36 chips for an ECC RDIMM). * **Technology:** Manufactured using a 20nm or 1xnm class process. * **Density:** Individual chips are usually 8Gb (Gigabit) or 16Gb density. * **x4 Organization:** This allows for advanced error correction (Chipkill) because data is spread across more physical chips. ### B. Register Clock Driver (RCD) As an **RDIMM**, this module includes a central "Register" chip. * **Function:** It buffers the address and control signals from the memory controller. * **Benefit:** This reduces the electrical load on the CPU's memory controller, allowing the system to support more DIMMs per channel without signal degradation. ### C. SPD EEPROM with Thermal Sensor * **SPD (Serial Presence Detect):** A small 4KB EEPROM chip that stores the module’s timing parameters, manufacturer info, and serial number. * **TS (Thermal Sensor):** Integrated into the SPD chip to provide real-time temperature monitoring to the system BIOS/BMC to manage fan speeds and prevent overheating. ### D. Decoupling Capacitors (MLCCs) * You will notice hundreds of tiny ceramic capacitors surface-mounted on the PCB. * **Purpose:** They filter electrical noise and provide local energy storage to stabilize the 1.2V power rail during rapid switching of the DRAM gates. --- ## 3. Physical Architecture ### VLP (Very Low Profile) Design The "B" in the suffix often denotes the height of the PCB. VLP modules are approximately **0.738 inches (18.75mm)** tall, compared to the standard 1.2 inches. * **Application:** Used in blade servers and 1U rackmount units to improve airflow. ### Gold Fingers The 288-pin interface features a curved edge to reduce the force required during insertion and to ensure better contact for high-speed signal integrity. ---