HMA42GR7AFR4N-TF Datasheet, Pinout, Equivalents, and Specs

The HMA42GR7AFR4N-TF is a high-density, 16GB DDR4 Registered Dual In-Line Memory Module (RDIMM) engineered by SK Hynix for enterprise-level computing systems. It operates at a standard voltage of 1.2V and features a data transfer rate of 2133 MT/s with a CAS Latency (CL) of 15. Organized as a dual-rank module with a x4 component configuration (2Rx4), it includes Error-Correcting Code (ECC) functionality, making it suitable for servers, workstations, and data center applications where data integrity and system stability are paramount.

What is the HMA42GR7AFR4N-TF?

The HMA42GR7AFR4N-TF is a JEDEC-compliant 288-pin DDR4 SDRAM Registered DIMM. Its internal architecture is defined by a 16GB capacity, achieved through a dual-rank (2R) organization using memory components with a 4-bit data width (x4). This 2Rx4 configuration means the module contains two independent, selectable memory areas (ranks), each constructed from eighteen 4-bit wide DRAM chips to create a 72-bit data bus. This 72-bit width comprises 64 bits for data and an additional 8 bits for Error-Correcting Code (ECC), which enables the module to detect and correct single-bit memory errors in real-time. This feature is critical for the high-reliability environments this module is designed for.

A key component of this RDIMM is the onboard Registering Clock Driver (RCD). The RCD acts as a buffer for all command, address, and control signals traveling from the system's memory controller to the DRAM chips. By re-driving these signals, the RCD reduces the electrical load on the memory controller, allowing for a greater number of memory modules to be installed per channel and enabling higher system memory capacities. This is a fundamental difference from unbuffered DIMMs (UDIMMs) used in consumer-grade systems. The module adheres to the PC4-2133P speed grade, signifying a peak data transfer rate of 2133 Megatransfers per second (MT/s) and a clock speed of 1066.5 MHz. It operates at a standard DDR4 VDD of 1.2V, contributing to lower power consumption compared to its DDR3 predecessors. The module also supports advanced DDR4 features such as Bank Grouping (4 groups), VrefDQ calibration, and Cyclic Redundancy Check (CRC) for command/address signals to further enhance data reliability and signal integrity at high speeds.

Pinout Configuration and Packaging

The HMA42GR7AFR4N-TF is packaged as a standard 288-pin DDR4 RDIMM, conforming to JEDEC specification MO-309. The physical dimensions are approximately 133.35mm x 31.25mm. The 288 gold-plated edge contacts are divided into two sides, with a keying notch positioned differently from DDR3 modules to prevent incorrect installation. The pinout is complex, designed to support high-speed differential signaling and provide a robust power delivery network.

Key pin groups include:

• Data Group (DQ[63:0] & ECC[7:0]): The 72-bit wide bidirectional data bus for transferring data between the memory controller and the DRAM chips.
• Data Strobe (DQS_t/DQS_c): Differential pairs that act as strobes for capturing data on the DQ lines. The 't' denotes the true signal and 'c' the complementary signal.
• Address & Command (A[17:0], BA[1:0], BG[1:0]): These pins carry memory addresses, Bank Address, and Bank Group information to select specific locations within the DRAM components.
• Control Signals (RAS_n, CAS_n, WE_n, CS_n): Critical control signals including Row Address Strobe, Column Address Strobe, Write Enable, and Chip Select, which manage read/write operations.
• Power and Ground (VDD, VPP, VSS): Multiple pins are dedicated to the primary 1.2V operating voltage (VDD), the 2.5V wordline boost voltage (VPP), and ground (VSS) to ensure stable power delivery across the module.
• Reference Voltage (VREFCA, VREFDQ): Provides a stable reference voltage for the command/address receivers and the data receivers, respectively, ensuring reliable signal interpretation.

The physical layout of the pins and the onboard DRAM components is optimized to minimize trace lengths and reduce signal reflection and crosstalk, which are critical considerations for maintaining signal integrity at 2133 MT/s data rates.

Core Architectural Features

• Registered Clock Driver (RCD): Incorporates an onboard RCD to buffer command, address, and clock signals. This reduces the electrical load on the memory controller, enabling higher memory density and improved signal integrity in systems with multiple DIMMs per channel.
• Error-Correcting Code (ECC): Features a 72-bit data path (64 data + 8 ECC) that supports single-bit error detection and correction. This is a non-negotiable feature for enterprise servers and mission-critical applications where data corruption cannot be tolerated.
• Dual Rank (2R) Organization: The module is structured with two independent ranks of DRAM chips. This allows the memory controller to interleave operations, accessing one rank while the other is refreshing, which can improve memory access efficiency in certain workloads.
• x4 DRAM Component Configuration: Utilizes DRAM components with a 4-bit data width. This configuration is common in high-capacity server DIMMs and is well-suited for systems that require robust error correction capabilities and high memory density.
• Low Voltage Operation: Operates at a standard JEDEC VDD of 1.2V, offering a significant power reduction compared to the 1.5V or 1.35V standards of DDR3 memory. This leads to lower operational costs and reduced thermal output in dense server environments.

Specifications Parameter Table

HMA42GR7AFR4N-TF Equivalents, Cross Reference & Lifecycle

The HMA42GR7AFR4N-TF is a mature component, generally considered to be in an End-of-Life (EOL) or legacy status for new system designs, but remains widely available for system upgrades and maintenance. When seeking equivalents, it is critical to match the core specifications: 16GB capacity, DDR4 type, 2133 MT/s speed, CL15 latency, 2Rx4 organization, 1.2V, and ECC RDIMM form factor.

Direct or near-compatible cross-references from other major manufacturers may include:

• Samsung: M393A2G40DB0-CPB
• Micron: MTA18ASF2G72PDZ-2G1B1

While these alternatives are functionally similar, system integrators must always verify compatibility by consulting the server or motherboard's Qualified Vendor List (QVL). Mixing memory modules from different manufacturers within the same memory channel is not recommended due to potential subtle timing differences that can lead to system instability. For sourcing and availability verification, it is advisable to Check HMA42GR7AFR4N-TF Inventory & Pricing from qualified distributors.

Typical Applications & Circuit Considerations

The HMA42GR7AFR4N-TF is engineered specifically for high-reliability, high-availability computing environments. Its primary applications are found in enterprise-grade systems where data integrity and uptime are critical operational metrics. These include:

• Data Center Servers: Used in rack-mounted and blade servers for virtualization, cloud computing, database management, and large-scale data processing. The ECC and registered features are essential for these multi-user, 24/7 operational environments.
• High-Performance Computing (HPC): Deployed in compute clusters and supercomputers for scientific research, financial modeling, and complex simulations where memory errors can invalidate extensive computations.
• Enterprise Workstations: Integrated into high-end workstations used for CAD/CAM, 3D rendering, and video editing, where large datasets must be manipulated without corruption.
• Network Infrastructure: Utilized in high-performance routers, switches, and network-attached storage (NAS) systems that require stable, error-free memory for packet buffering and processing.

From a circuit design perspective, integrating this module requires strict adherence to DDR4 layout guidelines. The Power Delivery Network (PDN) must be robust, with sufficient decoupling capacitors placed close to the DIMM socket's VDD pins to handle transient current demands. Signal integrity is paramount; PCB traces for data (DQ), strobe (DQS), and address/command lines must be impedance-controlled (typically 40-50 Ohms single-ended) and length-matched within their respective groups to prevent timing skew. Differential pairs like the clock and strobes must be tightly coupled and routed symmetrically. Thermal management is also a key consideration, as dense configurations of multiple DIMMs can generate significant heat, requiring carefully planned airflow within the chassis to maintain operating temperatures within JEDEC specifications. The selection of compatible components is crucial; engineers can Browse DDR4 Series to find other parts for their system designs.

Video Demonstration

Frequently Asked Questions (HMA42GR7AFR4N-TF FAQ)

Q: What does the "2Rx4" organization signify?

A: The "2Rx4" designation describes the module's internal architecture. "2R" stands for Dual Rank, meaning the module has two separate, addressable groups of DRAM chips that share the same data bus. "x4" indicates that each individual DRAM chip on the module has a 4-bit wide data interface. This combination is common in server memory as it allows for high density and robust ECC implementation.

Q: Can this RDIMM module be used in a standard desktop computer?

A: No, this module is an RDIMM (Registered DIMM) and is not compatible with most consumer desktop motherboards. Standard desktops typically use UDIMMs (Unbuffered DIMMs), which lack the Registering Clock Driver (RCD) found on this module. The motherboard's memory controller and BIOS must explicitly support registered memory, a feature almost exclusively found in server and workstation-class hardware.

Q: What is the function of the Registering Clock Driver (RCD) on this module?

A: The Registering Clock Driver (RCD) is a buffer chip located on the module itself. Its primary function is to receive command, address, and clock signals from the system's memory controller and then re-drive them to the DRAM chips. This buffering reduces the electrical load on the memory controller, which is critical for maintaining signal integrity in systems with many memory modules, allowing for greater total memory capacity and stability.

Q: Is the ECC feature important for my application?

A: The Error-Correcting Code (ECC) feature is critical for any application where data integrity is paramount. ECC memory can detect and correct single-bit memory errors on the fly, preventing data corruption that could lead to system crashes, silent data errors, or incorrect calculations. For servers, scientific computing, financial systems, and enterprise workstations, ECC is considered an essential requirement for reliability and stability.

Q: What is the difference between PC4-2133P and 2133 MT/s?

A: Both terms refer to the module's speed, but describe it differently. "2133 MT/s" stands for 2133 Megatransfers per second, which is the raw data rate of the I/O bus. "PC4-2133P" is the JEDEC standard naming convention, where "PC4" indicates DDR4 and "2133" is a rounded value of the theoretical peak bandwidth in MB/s (2133 MT/s * 8 Bytes/transfer ≈ 17000 MB/s, hence PC4-17000 is another name). The 'P' suffix in this context typically denotes the RDIMM module type. For practical purposes, they both signify the same performance level.

Alan Carter

Senior Hardware Engineer & Component Specialist

Alan has over 15 years of expertise in embedded systems design, FPGA architecture, and global semiconductor supply chains. He specializes in component cross-referencing, lifecycle management, and helping OEMs navigate supply shortages.