Found this link on the Yahoo! thread - sounds pretty good:
eetimes.com
Broadcom, Vitesse apply CMOS to 10-Gbit
Ethernet chips
By Craig Matsumoto
EE Times
(05/03/00, 12:51 p.m. EST)
SAN MATEO, Calif. ? Broadcom Corp. (Irvine, Calif.) announced its first chip for fiber-optic
communications on Tuesday (May 2), and laid claim to having the market's first transceiver produced
in CMOS for the still-undefined 10-Gigabit Ethernet standard.
The Broadcom BCM8010 is the company's first chip for fiber-optic networks, an area where
Broadcom hopes to excel through its use of CMOS, which is cheaper that material such as gallium
arsenide used by other suppliers of high-speed chips.
But competitors are already at work on similar CMOS devices, which are due to ship at around the
same time as Broadcom's.
Vitesse Semiconductor Corp. (Camarillo, Calif.) has a 0.18-micron CMOS transceiver "well in the
works" that should begin sampling this summer, said Frederick Weniger, product marketing manager
for Vitesse.
It is a bit premature to state that any of these parts will handle 10-Gigabit Ethernet, as the specification
hasn't been set yet, Weniger said. The committee for the 10-Gbit/s Ethernet standard, dubbed IEEE
802.3ae, has only recently been formalized by the IEEE and isn't expected to have its first draft
standard ready until September. A finalized draft is still more than a year away.
Better known for network-access components and copper-driven networks, Broadcom is using
10-Gigabit Ethernet as its launch pad into fiber-optic networking, and possibly into wide-area
networking as well.
The BCM8010 targets 10-Gbit/s Ethernet, an important distinction from Sonet's OC-192 speed
grade, said Marty Colombatto, vice president of Broadcom's networking business unit. OC-192 is
slightly slower than 10 Gbit/s, Colombatto said, but the Sonet jitter requirements are more stringent
than those of Ethernet. Broadcom went for the Ethernet speed grade and a better-than-Sonet jitter
level.
"To be able to achieve the clock jitter in CMOS is something nobody's been able to do," Colombatto
said.
The part is also Broadcom's first to implement adaptive equalization in the receiving channel, a feature
which compensates for the signal distortion that occurs during transit through fiber-optic cables.
Crucial core
Crucial to the BCM8010 is FutureCore, a physical-interface core that will form the basis of a family of
products for Broadcom. FutureCore handles functions such as multiplexing and 8-bit/10-bit encoding,
but most significantly, the core can handle signals with jitter that exceeds Sonet specifications, which
are more strict than those for Ethernet.
FutureCore's jitter reduction comes from a voltage-controlled oscillator that Broadcom developed for
use in its tuners.
Broadcom officials see FutureCore becoming the basis for transceivers addressing other protocols,
such as Sonet or the Infiniband I/O standard, and the company also hopes to make transceivers for
backplanes or for box-to-box connections inside the central office, Colombatto said.
Vitesse has taken the opposite approach, and has groomed its 10-Gbit/s transceiver for customers
who want raw 10-Gbit/s transmission for backplanes and who aren't concerned with conformance to
Ethernet standards.
Broadcom's decision was simple because the company's backplane customers had more immediate
demands, the company said. In fact, the BCM8010 includes some features ? such as redundant I/O
? that are requirements for backplanes but aren't likely to be included in the 10-Gigabit Ethernet
spec. "As the 10-Gigabit Ethernet specification becomes firm and resolved, if there's any tweaking we
have to do with the 7226 [Vitesse's 10-Gbit/s chip] to make it compliant, we'll be able to do that,"
Weniger said.
Vitesse's yet-unannounced 7226 chip will accept a 32-bit-wide stream from an Ethernet MAC and
treat it as one, two or four channels ? different OEMs have been pushing for each of the three
options, Weniger said.
The Vitesse part, due to begin sampling in the summer, will be built in 0.18-micron CMOS and will
contain four channels, each capable of handling 3.125 Gbit/s, or enough to handle a 10-Gbit/s stream
that's been run through an 8-bit/10-bit encoder.
Failing major advances in CMOS technology, Broadcom might be forced to go to more exotic
processes to reach OC-768 (40-Gbit/s) speeds, as CMOS isn't yet considered viable for that speed.
Vitesse, for one, has declared indium phosphide as its material of choice for future 40-Gbit/s parts.
Colombatto declined to comment on any of the company's plans beyond 10-Gbit/s devices. |
