Perspective on embedded dram from 6/7/99
Copyright 1999 CMP Media Inc.
Electronic Buyers' News
June 7, 1999
LENGTH: 586 words
HEADLINE: S3 eschews embedded DRAM for MCMs
BYLINE: Mark Hachman
BODY:
Silicon Valley- Despite the buzz surrounding the performance advantages of embedded DRAM, one of the industry's largest graphics-chip makers has found that manufacturing difficulties can sometimes outweigh technical promise.
Having tried and failed to embed DRAM in its mobile-graphics IC line, S3 Inc. has returned to a more traditional approach and is offering its latest devices in multichip modules (MCMs), according to Carrell Killebrew Jr., director of mobile marketing at the Santa Clara, Calif., company.
The decision stems from a host of issues associated with the cost, yield, and turnaround time of the embedded-DRAM process, issues serious enough to cause S3 last year to kill its MXi mobile-graphics chip and an unannounced successor, the MI6.
Instead, the company's latest mobile chip, the Savage/IX, uses an MCM that combines 4, 8, or 16 Mbytes of SGRAM and a low-power version of the Savage3D core inside a 385-pin BGA. A second graphics IC, the Savage/MX, takes an even more discrete tack, consisting of a stand-alone Savage core that draws from off-chip SDRAM or SGRAM.
With so much attention being paid to embedded DRAM, only a few notebook- graphics suppliers-S3, ATI Technologies, and Silicon Motion-are willing to espouse the MCM strategy, according to Jon Peddie, an analyst at Jon Peddie Associates, Tiburon, Calif. Intel, NeoMagic, Silicon Magic, and Trident Microsystems, on the other hand, all use embedded memory in their graphics programs.
According to Killebrew, OEM customers were attracted by the $3 to $4 in savings afforded by embedded DRAM, and to a lesser extent by its lower electromagnetic interference and reduced power consumption.
However, S3 soon found that yields of the MXi were intolerable. "I was looking at yield reports from four batches," Killebrew said. "The first one was 90%. The next three were zero, zero, and zero, and the reasons why they were all zero were all different."
Peddie said low yields may have been due to S3's choice of foundry. "What it comes down to is whether you're using a memory fab that's adding logic, or a logic fab that's adding memory," he said. "The logic fabs adding memory are having yield problems."
At the time of its strategy shift, S3's embedded-DRAM supplier was United Microelectronics Corp., the same foundry that is building the Savage/IX.
For S3, the last straw came when both UMC and a second foundry said they would need about 90 days to return silicon after each design revision. "And that was on a 2D product," Killebrew said. "In a 3D part, we'd need to do more turns, not less turns."
Santa Clara-based NeoMagic Corp. acknowledged the higher number of mask steps an embedded-DRAM process requires, but said the technology's benefits overpower the manufacturing hurdles. "The issues S3 is talking about are not new," said Prakash Agarwal, president and chief executive of NeoMagic. " We faced the same challenges when we started the company."
S3, meanwhile, hopes the 500-plus 3DWinBench '99 performance benchmarks expected of the two mobile parts will yield new design wins. A total of 16 Mbytes of frame buffer memory allows high-performance graphics across two monitors, while an integrated motion-compensation engine will speed DVD playback, the company said.
In 1,000s, the Savage/IX with 4 Mbytes of frame buffer DRAM costs $49, an 8- Mbyte version is priced at $56, and a 16-Mbyte model is $68. The SavageMX sells for $42 in like quantities.
Copyright 1999 CMP Media Inc.
LANGUAGE: ENGLISH
LOAD-DATE: June 5, 1999
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