Memory Interfaces – The Memory Guy

Memory Market Falling, as Predicted

It’s earnings call season, and we have heard of a slowing DRAM market and NAND flash price declines from Micron, SK hynix, Intel, and now Samsung. DRAM prices have stopped increasing, and that can be viewed as a precursor to a price decline.

Samsung’s 31 October, 2018 3Q18 earnings call vindicated Objective Analysis‘ forecast for a 2H18 downturn in memories that will take the rest of the semiconductor market with it.

Those familiar with our forecast know that for a few years we have been predicting a downturn in the second half of this year as NAND flash prices fall, followed by a DRAM price collapse. After the DRAM collapse the rest of the semiconductor market will undergo a downturn.

We’ve been calling for this downturn for some time. Dan Hutcheson at VLSI Research has been videotaping our forecast every December for the past Continue reading “Memory Market Falling, as Predicted”

Samsung’s Colossal 128GB DIMM

In a November 25 press release Samsung introduced a 128GB DDR4 DIMM. This is eight times the density of the largest broadly-available DIMM and rivals the full capacity of mainstream SSDs.

Naturally, the first question is: “How do they do that?”

To get all the chips into the DIMM format Samsung uses TSV interconnects on the DRAMs. The module’s 36 DRAM packages each contain four 8Gb (1GB) chips, resulting in 144 DRAM chips squeezed into a standard DIMM format. Each package also includes a data buffer chip, making the stack very closely resemble either the High-Bandwidth Memory (HBM) or the Hybrid Memory Cube (HMC).

Since these 36 packages (or worse, 144 DRAM chips) would overload the processor’s address bus, the DIMM uses an RDIMM protocol – the address and control pins are buffered on the DIMM before they reach the DRAM chips, cutting the processor bus loading by an order of magnitude or more. RDIMMs are supported by certain server platforms.

The Memory Guy asked Samsung whether Continue reading “Samsung’s Colossal 128GB DIMM”

Why ST-MRAMs Need Specialized DDR3 Controllers

Everspin and Northwest Logic have just announced full interoperability between Northwest Logic’s MRAM Controller Core and Everspin Technologies’ ST-MRAM (Spin-Torque Magnetic RAM) chips. This interoperability is hardware proven on a Xilinx Virtex-7 FPGA and is now available for designs needing low-latency, high memory throughput using MRAM technology.

Since The Memory Guy knew that Everspin’s EMD3D064M ST-MRAM was fully DDR3 compatible, I had to wonder why the part would require a special controller – couldn’t it simply be controlled by any DDR3 controller?

Everspin’s product marketing director, Joe O’Hare, took the time to Continue reading “Why ST-MRAMs Need Specialized DDR3 Controllers”

Intel to Use Micron Hybrid Memory Cube

Intel and Micron today announced that the new version of Intel’s Xeon Phi, a highly parallel coprocessor for research applications, will be built using a custom version of Micron’s Hybrid Memory Cube, or HMC.

This is only the second announced application for this new memory product – the first was a Fujitsu supercomputer back in November.

For those who, like me, were unfamiliar with the Xeon Phi, it’s a module that uses high core-count processors for problems that can be solved with high degrees of parallelism. My friend and processor guru Nathan Brookwood tells me Continue reading “Intel to Use Micron Hybrid Memory Cube”

Spansion’s Super-Fast HyperFlash NOR

Spansion recently introduced a NOR flash that the company boasts is the: “World’s fastest NOR flash memory”. Named HyperFlash, the chip taps into high-speed SPI interface, doubling its width and adding a differential clock to run at an I/O rates as high as 333MB/s.

In this post’s graphic (click to enlarge) Spansion compares the HyperFlash chip’s sustained read rate (right-hand column) to that of (from left to right) asynchronous parallel NOR, single-bit SPI, industry-standard DDR Quad SPI, and Spansion’s faster rendition of DDR Quad SPI, which Spansion tells us, until now, has been the fastest flash on the market. The company points out that HyperFlash is five times the speed of industry-standard Continue reading “Spansion’s Super-Fast HyperFlash NOR”

Rambus and Micron Sign License Agreement

The following is excerpted from an Objective Analysis Alert that can be downloaded from the company’s website.

Rambus and Micron announced on Tuesday that they have signed a patent cross license agreement. Micron receives rights to Rambus IC patents, including memories. Both Micron and Elpida products will be covered. The companies have thus settled all outstanding patent and antitrust claims in their 13-year court battle.

Micron will make royalty payments to Rambus of up to $10 million per quarter over the next seven years, totaling $280 million, after which Micron will receive a perpetual, paid-up license.

Rambus and Micron both have Continue reading “Rambus and Micron Sign License Agreement”

Micron Samples Hybrid Memory Cube

Today Micron Technology announced that it is sampling the Hybrid Memory Cube (HMC) a DRAM packaging technology that it has been working on with the HMC Consortium.

Micron has been pushing to rapidly advance the HMC’s development and seems to have reached this point in an impressively brief time, given the complexity of the technology. It has only been two years since the first public appearance of the HMC at the 2011 Intel Developer Forum.

Some pretty advanced technology was used to make this product. DRAM processes are not very good at Continue reading “Micron Samples Hybrid Memory Cube”

What is cMLC Flash?

Some recent news mentioned cMLC flash, which is short for “consumer MLC.” This term is used to differentiate between the cheapest available product, mainstream MLC, and products that are aimed at the computing segment, and thus carry higher price tags.

There are several of these higher-end products. Some have longer endurance, like eMLC and SLC flash. Some have faster interfaces, like ONFi and Toggle Mode. Then there are the combinations of these: a fast interface with enhanced reliability.

There are disadvantages to these. The consumer market Continue reading “What is cMLC Flash?”

Invensas’ DIMM-in-a-Package

Tessara’s Invensas subsidiary has announced a new packaging technology to produce what the company calls a “DIMM in a Package.”

The new product is said to deliver the capacity and performance of an SO-DIMM in a 16x16mm BGA. It is built using Invensas’ xFD technology.

I have seen examples of Invensas’ xFD and the first thought that struck me was: “Why didn’t I think of that?!?” It’s an elegantly simple approach to today’s connection conundrums. By staggering chips and mounting them face-down over holes for bonding wires the company connects DRAMs with far shorter interconnect lengths and less scrambling, leading to higher performance.

Although this technology is not yet covered in any of our current reports, we do have a report on cell phone packages: Flash Packaging: What Phone Makers Want and Why, that can be purchased for immediate download on the Objective Analysis website.

WIOMING: Another Spin on the Hybrid Memory Cube

At a Conference in San Francisco today (Tuesday December 13 ) ST-Ericsson and CEA-Leti presented a paper on something the companies called a: “Breakthrough 3DIC with Wide I/O Interface.”

This product appears to be a variation on the Hybrid Memory Cube, or HMC concept detailed in a prior post.

Remember that the HMC stacks a number of DRAM chips atop a logic chip. The memories store data and communicate to the logic chip through thousands of through-silicon vias (TSVs) while the logic chip handles communications with the outside world. Continue reading “WIOMING: Another Spin on the Hybrid Memory Cube”