Micron DDR4 Ordering Code Guide

The quick answer: decode the product class before the characters

A Micron DDR4 identifier is safe to decode only after you know what physical item it names. MT40A1G8SA-062E IT:R identifies one packaged DDR4 SDRAM component. MTA8ATF1G64HZ-3G2J1 identifies one assembled SO-DIMM containing multiple DRAM components. A five-character code beside an MT mark on an FBGA package is an abbreviated physical mark that must be resolved through Micron's decoder.

Technical facts in this guide were rechecked against current Micron resources on 28 August 2026. Product status and document revisions can change; reopen the exact record when quoting or approving material.

Component, module, top mark, and trace data answer different questions

These layers are easy to mix because a module carries both a module label and several component top marks. The module part number tells purchasing what assembled product to order. The codes on the mounted DRAM packages identify the ICs used on that assembly. SPD data gives firmware a structured description of the module. Packing labels add order and traceability evidence.

At incoming inspection, do not force all visible strings into one field. Store the manufacturer part number, component or module class, top mark, date code, lot/build code, serial number, and supplier or customer reference separately. That makes later discrepancies visible instead of silently overwriting one identifier with another.

The physical form tells you which decoder to open

A full-size DDR4 DIMM and a compact SO-DIMM may use related module numbering rules, but neither is a bare component. A board design that solders DDR4 ICs needs the component number, package drawing, and controller qualification. A computer or service BOM that plugs memory into a socket needs the complete module identity, form factor, SPD, ranks, and platform acceptance.

When an RFQ says only “Micron DDR4 8GB 3200,” ask whether 8GB means module capacity, whether 3200 means MT/s, and whether the requirement is a DIMM, SO-DIMM, or soldered component set.

Worked component: MT40A1G8SA-062E IT:R

Micron's DDR4 component catalog makes this a useful documented example. The current row lists an 8Gb x8 DDR4 SDRAM component in a 78-ball TFBGA package measuring 7.50 × 11.00 × 1.20mm. It operates at 1.2V, is listed at 1600MHz clock and 3200MT/s, has CL22, carries a −40°C to +95°C operating range, and was marked Production when checked.

This segmentation applies to the documented MT40A example. Confirm any other code in its own current Micron ordering table and product record.

1G8 describes organization, not “8GB”

The organization calculation is straightforward: one giga-scale set of addressable locations multiplied by eight bits equals 8 gigabits. Eight bits make one byte, so the raw capacity of one component is 1 gigabyte. Capitalization matters: Gb means gigabits; GB means gigabytes.

The x8 width also describes the component's data I/O. An x16 device with the same total 8Gb density has a different depth, ballout, controller loading, board population, and possibly different timing or refresh constraints. Equal density and equal advertised transfer rate do not establish a substitute.

-062E separates the physical clock from DDR transfer rate

For this exact speed grade, a 0.625ns clock period corresponds to 1.6GHz, or 1600MHz. DDR transfers data on both clock edges, giving 3200 million transfers per second. Thus 1600MHz clock and 3200MT/s data rate describe the same operating point from two different perspectives.

Micron lists CL22 for the example. Multiplying 22 cycles by 0.625ns gives a nominal 13.75ns CAS interval. That is not total memory-access latency. Row activation, precharge, refresh, controller queues, training, board topology, and the full timing set still matter.

Evidence: Micron's current DDR4 SDRAM part catalog. YURUNOX is an independent sourcing partner and does not define or manufacture Micron products.

Worked module: MTA8ATF1G64HZ-3G2J1

Micron's module numbering guide uses a different field map from the MT40A component family. The exact module appears in Micron's obsolete SO-DIMM catalog as an 8GB non-ECC DDR4 SO-DIMM with eight components, a x64 module bus, 1.2V operation, 1600MHz clock, 3200MT/s, PC4-3200, and CL22.

Eight 8Gb components provide 64Gb of raw bit capacity; dividing by eight gives the module's 8GB capacity. Each x8 component contributes eight data lines. Eight components therefore provide the 64-bit data path of this non-ECC module. An ECC module usually adds check-bit capacity and uses a different organization, so “8GB DDR4-3200” is not enough to compare them.

SPD is a configuration record, not a replacement for the module label

Micron's public SPD view for MTA8ATF1G64HZ-3G2J1 identifies DDR4 as the device type and SO-DIMM as the module form factor. It also contains the module part-number field and records PCB and DRAM-die revision information. Firmware reads SPD so it can configure compatible timings and organization.

A physically fitting alternative can still fail platform validation because of ranks, DRAM organization, SPD programming, firmware limits, or controller training. For service replacements, collect the approved module number and a known-good SPD record before evaluating substitutes.

Evidence: Micron Module Part Numbering Systems, obsolete SO-DIMM catalog, and exact SPD data.

How to resolve a Micron FBGA top mark without guessing

Space on an FBGA component is limited, so Micron uses abbreviated marks. Its official decoder says the relevant FBGA code is the second five-character code on the chip marking and is typically preceded by an MT mark. Enter that code in Micron's decoder to obtain the corresponding full part number. The tool can also work in reverse from a full part number to an FBGA code.

Use a five-evidence reconciliation

1. Photograph the complete package square-on under diffuse light; preserve every line, logo, orientation dot, and character.
2. Locate the five-character code in the position described by Micron rather than choosing any convenient five characters.
3. Resolve it through the official decoder. If there are multiple results or no result, recheck the image and escalate instead of filling in missing text.
4. Compare the returned part number with the reel/tray label, supplier documents, approved BOM, and exact product record.
5. Verify package dimensions, ball count and ballout, density, organization, speed, temperature, revision, and lifecycle.

Micron's May 2026 CSN-11 adds an important warning: the upper mark row can contain date, die revision, and country information, while product-specific coded identity sits in other mark rows. A short character group may therefore be trace data rather than the part code a buyer is trying to decode.

Legacy Elpida products are a separate path. Micron's CSN-11 says legacy products with Elpida marks retain the earlier marking approach. Do not force an EDY... identifier through the MT40A component pattern; use the applicable legacy guide and product documentation.

Evidence: Micron's FBGA and part marking decoder and CSN-11: Product Marks, Product Labels, and Packaging Labels.

Documented case study: a clean decode can still lead to opposite purchasing decisions

This public comparison is stronger than a generic warning because it shows the decision consequence. An ordering code tells you what an item is; it does not guarantee availability, longevity, channel authorization, or a recommended new-design status. Recheck current catalogs, product-change notices, discontinuance notices, last-time-buy conditions, and approved alternatives at the moment of purchase.

Use this seven-step decoding and approval workflow

1. Capture the complete string and physical context.Keep spaces, hyphens, colons, case, and suffixes. Photograph the full item, top mark, module label, contacts or ball field, inner pack label, and outer label.
2. Classify the identifier.Decide whether it is a component number, module number, five-character FBGA mark, date/lot code, process code, supplier cross-reference, or customer number.
3. Open the matching Micron guide.Use the component ordering table for the exact DRAM family, the module numbering guide for DIMMs/SO-DIMMs, or the official decoder for abbreviated marks.
4. Decode only documented fields.Record density, organization, package, voltage, speed, temperature, revision, module type, ECC, ranks, and SPD as separate attributes. Leave undocumented positions unresolved.
5. Confirm the exact manufacturer record.Check the current catalog row or part detail, datasheet, package drawing, SPD data where applicable, and any family-specific technical note.
6. Qualify compatibility and lifecycle.Compare pinout/ballout, dimensions, full timing set, controller support, qualification, revisions, PCNs, product status, date-code policy, and platform acceptance.
7. Freeze the approved identity and evidence.Store the complete manufacturer part number, allowed revisions, required documents, packing, label fields, source channel, and receiving acceptance criteria without wildcards that erase important suffixes.

Evidence checklist tool: choose what you have and what you need to decide

This tool does not fabricate a decoded part number. It returns the minimum evidence path for an RFQ, substitution review, or incoming-inspection decision.

Turn the decoded code into an RFQ and receiving control

YURUNOX is an electronic-component sourcing partner, not a semiconductor manufacturer. Micron's current documentation remains the technical authority. The sourcing task is to connect the approved manufacturer identity with clear commercial, lifecycle, traceability, packing, and inspection requirements.

RFQ fields that prevent avoidable clarification loops

• Exact identity and class.Micron as manufacturer; complete ordering code; component, UDIMM, RDIMM, SO-DIMM, or other assembly; customer-number mapping.
• Electrical configuration.DDR generation, density/capacity, x4/x8/x16 or x64/x72 organization, ECC, ranks, registered/unbuffered status, voltage, speed grade, full timing requirement, and controller/platform.
• Mechanical configuration.Package code, ball count and approved drawing revision for components; module type, keying, dimensions, height, contacts, and socket for modules.
• Environment and revisions.Temperature grade, qualification, accepted die revision, PCB revision, SPD baseline, PCN/errata requirements, and prohibited substitutions.
• Lifecycle and commercial boundary.Current manufacturer status, approved alternative, quantity, target delivery, date-code limits, new/unused condition, and disclosure of obsolete or residual-stock risk.
• Traceability and quality evidence.Authorized-source or chain-of-custody documents, certificate of conformance, manufacturer and packing-label photos, lot/date data, country/origin fields, and agreed inspection or test evidence.
• Packing and handling.Tray/reel/module box requirement, dry pack, moisture sensitivity controls, humidity indicator and desiccant where applicable, quantity per pack, and shipping protection.

Incoming inspection should reconcile—not merely read—a code

Compare the purchase order, supplier paperwork, inner and outer labels, and physical item. Verify that the full ordering code is present where expected and that the package mark or module label is consistent with the official decoder or documentation. Inspect packing condition, moisture barrier and indicators where applicable, tray/reel or module-box identity, quantity, lot and date information, contacts or balls, package condition, and signs of relabeling or rework.

For modules, archive SPD data when the risk, volume, or service process justifies it. For components, compare body dimensions and ball field with the approved package drawing. Quarantine mixed revisions, unexplained label-to-device mismatches, missing temperature or revision suffixes, inconsistent date/lot formats, and any substitute offered without written approval.