Dave and thread,
Long but very thorough and with much detail-- notice 2B RDRAMs shipped in '01. <gg> Dave, also seems to support your "fast ramp up" to RDRAM theory (faster than some might be expecting)....
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March 01, 1999, Issue: 1149
Section: Extra: Connectors
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RIMM sockets ready to roll
Gina M. Roos
Anticipating the emergence of Direct Rambus DRAM technology, three connector powerhouses are getting in gear to provide the required sockets.
Rambus Inc. has granted AMP Inc., FCI Electronics, and Molex Inc. licenses to manufacture Rambus-in-line memory module sockets. The three interconnect companies will hold exclusive licenses to manufacture the RIMM socket for one year once the spec is released.
Industry observers expect the memory technology to take off, despite some talk that its release, originally slated for midyear, will be delayed.
A key question, however, is whether AMP, FCI , and Molex will reap benefits from being at the forefront of the technology, particularly if RIMM sockets quickly go the way of a typical high-volume, commodity-type PC connector. Some observers expect knock-offs to start appearing in the market around midyear.
"Although it's a very similar product to the DIMM socket, the electrical [work is] technically challenging, so [Rambus] wanted to ensure that the suppliers would be capable of developing the connector to meet those needs," said Mike Evans, product manager at FCI , Etters, Pa.
RIMM-socket suppliers also have to be capable of achieving volume production to support global demand, Evans added.
Developers of Rambus components expect products to start shipping with Direct Rambus systems for main memory by the second quarter.
Market researchers see high growth potential over the next two years as the memory market migrates from SDRAM to Direct Rambus.
Shipments of SDRAM chips are projected to drop to 1.4 billion units in 2001 from 2 billion in 1998, according to Fleck Research, Santa Ana, Calif. In comparison, Rambus chip shipments will grow to 2 billion units in 2001 from 100,000 in 1998.
Analysts note that systems using the new memory architecture will each use three RIMM sockets.
Bringing the systems to high-volume production won't be contingent on the socket suppliers, because other parts are involved, including chipsets and memory modules. High-performance PCs will likely be the first market for Rambus main memory.
"It's going to be tight through the first half of this year, but we'll keep up," said Jim Leidy, marketing manager for the PC Division of AMP, Harrisburg, Pa.
"We'll be ready," said Kevin Alberts, product marketing manager at Molex, Lisle, Ill. "What the market seems to be indicating is that we should see some significant orders coming through in the second quarter."
The availability will hinge on the chip makers' production, even though a lot of companies have signed on, including Hitachi, Micron, Mitsubishi, Samsung, and Toshiba, according to Bob Million, vice president of international operations at Fleck Research. The question is whether they're going to continue to focus on Rambus technology, or delve into alternate technologies such as double-data rate (DDR), Million added.
But Intel Corp. has made some hefty investments in IC makers such as Samsung Electronics Co. Ltd. and Micron Technology Inc. to ensure a steady supply of Direct RDRAMs.
Performance issues
Rambus technology raises new design issues for connector makers. The greatest challenge is meeting low-inductance and low-capacitance specs. Since RIMM sockets need to meet the demand for higher-speed signal transmission of 800 MHz and increased bandwidth of 1.6 Gbytes/s, connector makers initially struggled with low-inductance and low-capacitance requirements.
Other issues put stress on RIMM-socket development, compared with either the single-in-line memory module (SIMM) or the dual-in-line memory module (DIMM), Million said.
These issues center primarily on speed and bandwidth. Extra care has to be taken on inductance, capacitance, crosstalk, and signal-to-noise ratio specifications.
Form factor isn't a problem since RIMMs fit the DIMM configuration. The RIMM connectors are available in either 168- or 184-contact versions on 1-mm centerlines. They feature inductance and capacitance of 2 nHand 1 pF, respectively, and a 1:1 ratio of signal/ground contacts.
The speed and performance requirements of this serial bus require an electrically tuned socket, Molex's Alberts said. The new socket fits into the same physical format of the DIMM, and due to specially designed contacts, it can handle high speeds and low-inductance requirements of the Direct Rambus system, he said.
Certainly, Direct Rambus technology has come a long way since the first 30-circuit, 0.1-in.-pitch SIMM was introduced for bus speeds of 33 MHz. Over the past five years, the DIMM socket has dominated the market, handling bus speeds up to 100 MHz.
The initial 168-circuit connector for Direct Rambus memory modules has moved to a 184-circuit design to allow for some extra circuitry for SDRAM chips in the event that RDRAM modules aren't available.
Delivery
Molex will begin shipping RIMM connectors as early as October with a lead time of eight to 10 weeks. The 184-circuit socket is $1.95 in 25,000s. Molex also offers a 168-circuit device.
FCI offers samples, and is in the initial phase of volume production to handle capacity for the foreseeable future. Delivery is two weeks.
FCI prefers not to release pricing yet because order quantities are still small and don't reflect what pricing will be once the technology is shipped in volume, according to Evans.
AMP currently has low-volume production and is "ramping up as fast as we can," Leidy said. Like FCI, orders coming into AMP are for small quantities-500 to 1,000 pieces. Lead time is four weeks. He expects pricing to fall to 60 cents for quantities of 100,000.
Ramping up for Rambus was different from previous generations of memory modules for several reasons, according to connector makers.
"This has a higher ramp-up curve than what we've been typically used to," Evans said. "It's all the front-end preparation that's going to make this ramp go quicker than in the past."
Evans said the consortium responsible for preparing Direct Rambus for market has worked extremely hard. "We expect a shift to Direct Rambus memory in large numbers, as compared to the adoption of some other memory technologies in the past, which have taken a bit longer," Evans said.
Late last year, for example, a component validation program was unleashed to accelerate the transition to Direct Rambus memory systems. This established uniform verification procedures for the components, including Direct RDRAM chips, RIMMs, RIMM connectors, and clock ICs.
Ramping up for the Rambus architecture differs significantly from previous memory modules, primarily in the way the program was driven, AMP's Leidy said.
In this case, Rambus and Intel are driving the development, instead of semiconductor manufacturers, through the Joint Engineering Device Electronics Council, Leidy said.
"It's not that it made it more difficult, but you have to take into consideration the risk of where the industry is headed in terms of architectures," he said.
Also, the stringent electrical performance specs and tight tolerance requirements demanded that the manufacturers work closely with Rambus and Intel early in the development cycle.
The big issue wasn't the 1-mm pitch vs. the 0.05-mm centerline of the DIMM; it was electrical performance, specifically the 2-nH maximum inductance, said Wayne Zahlit, director of engineering at FCI's Commercial Division.
"You have to be able to measure the inductance and capacitance of the connector separately, and it took some new equipment to do that," Leidy agreed. "Not only are we measuring inductance and capacitance, the tolerance on each spec is tighter, which is a function of the mechanical design."
The overriding factor was how to design the connector with every change affecting the electrical performance, Leidy said. The objective was to make it not too different from what's on the market today, while keeping it at a low cost, he said.
Rambus vs. DDR
Despite Rambus' impressive following, competing architectures such as DDR are gaining ground.
Some connector suppliers say the new DDR SDRAMs offer a smoother, less costly transition than Rambus. They believe that if Intel didn't back Rambus, there wouldn't be a question about the transition to the next new high-performance DRAM technology for main memory in PCs.
The DDR architecture's low cost is a clear benefit, Leidy said, pointing to the fact that AMP has already produced a 184-circuit DDR socket.
The technology's acceptance will come down to one thing-total applied cost to the memory bus, according to Leidy.
Molex is also supporting DDR technology with DDR-type sockets. "Availability could determine which architecture is more prevalent in the beginning," Alberts said. "One of the architectures may lend itself better to a different platform, so you need to have both bases covered-not because of who wins or who loses, but different architectures may be more prevalent either early on or later for different market segments."
Alberts believes workstation and server makers will turn to DDR, but ultimately it will depend on availability and pricing.
While FCI is not currently working on DDR-based interconnects, the company is keeping an eye on the technology.
What the industry is hearing is that DDR is much less expensive to make and easier to implement. "And with many of the computer OEMs hopping on the DDR bandwagon, I don't know how much that's going to derail the Rambus express," Fleck Research's Million said.
Million believes Direct Rambus will be used in high-end servers and workstations rather than desktop PCs.
"Yet the idea is to ramp up Rambus to such a high production rate and get the price down low enough so that the desktop PC OEMs will migrate to Rambus," he said.
But speed appears to be as important as price, and it is at this fork in the road that Direct Rambus and DDR technology may go their separate ways. High-end desktop machines with a need for speed will probably use the Rambus solutions, while DDR will be used in the ubiquitous consumer PC.
-Gina Roos is a freelance writer based in Plymouth, Mass.
Copyright ® 1999 CMP Media Inc.
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