i/oZONE Products for the week of May 31, 2004
Mysticom Semiconductor Says . . .
Mysticom's CX4 Module-In-A-Chip Enables Up To 80%
Cost Savings For 10-Gigabit Links
Innovative design delivers 2x standard distance and permits
use of thin gauge cables
Mysticom Semiconductor has introduced the MY3126, a highly integrated CX4 silicon solution that addresses the need for cost-effective 10 Gigabits per second (Gbit/s) links in the enterprise.
The lack of cost-effective 10-Gbit/sec uplinks is a major factor preventing the deployment of gigabit-speed switching at the desktop. Today's delivery options, such as optical and multiple-gigabit links are costly and sub-optimal, respectively. Mysticom's CX4 solution enables an 80% cost savings over current 10-Gbit/sec industry solutions.
According to Wiren Perera, Mysticom vice president of marketing, "Mysticom not only had a major impact on establishing the CX4 standard, but is the first to deliver this class of performance in a "module in a chip." The MY3126 is reliable at distances of 30m at 10 Gbits/s, making it ideal not only for the stackable market segment, but much of the data center as well. We're continuing to solve the issue of distance vs. cost over both copper and fiber, while exceeding industry standards," said Perera.
Adjustable link parameters reduce inter-symbol interference; improve
jitter; and offer impedance control and NEXT/FEXT impairment reduction.
An optional integrated FECon each channel reduces BER, while extending signal
distances even further. The small-footprint IC integrates XENPAK registers
and an oscillator; only the crystal and EEPROM remain external to the chip.
User-programmable Tx and Rx pins are assigned for optimized layouts, enhancing
performance, lowering power, and reducing cost.
analogZONE Says . . .
If Mysticom has truly been able to make good on its claims for doubling the reach of the CX4 (and the proposed LRM MMF) short-haul interconnect standard, they could greatly accelerate the acceptance of this technology for both enterprise and storage applications. But extended reach is only one of the market challenges that the designers needed to tackle when they set out to design the MY3126. While there is a growing need for 10-Gbit/s interconnects, they often must run over an enterprise's existing cable Infrastructure which is often heterogeneous, and does not always meet the standards for CX-4 media.
To achieve this, they are capitalizing on some of the design skills and
technologies they developed when Mysticom was in the business of producing
high-performance mixed-signal IP cores for other chip makers. They've pulled
out all the stops and are using a combination of Adaptive (analog &
digital) equalization, forward error correction, and dispersion compensation
techniques to cram the best possible link performance into their mixed-signal
PHY (See the block diagram).
Conversations with Mysticom's engineering staff revealed that they took a sensible approach to channel equalization, using both analog and digital technologies where they made the most sense in terms of performance and power. On the transmitter, for example, they use a relatively simple pre-emphasis scheme that can be programmed to give between a 0 to 80% boost to the leading edge of the signal. They've found that somewhere between 21% and 40% usually works best for CX4 applications, and varies a bit more in backplane applications. The fixed-level, non-adaptive pre-emphasis is nothing fancy, but it's effective at compensating for the losses in CX4 where the cable shields potential inter-channel crosstalk generated by the over-driven signals. But if you really need an adaptive solution, Mysticom says they've successfully used an out-of-band backchannel to provide the necessary control loop.
On the receive side, the MY3126's EQ uses digital oversampling to extract a clean clock and clean up "out of spectrum" noise components. This helps it compensate for channel fading from thermal noise and other factors that can create 1-bit errors. We discussed a couple of other proprietary technologies that they use in their receiver in some detail, but I cannot comment on them other than to say that I believe that they will yield a better link error budget than conventional chips.
In keeping with their mission of equipping their chip to perform well under challenging conditions, the engineers have also provided it with extra-deep alignment buffers. They are 70 bit deep (vs. 40 bit standard) to handle the extra skew generated in long links. The result of Mysticom's attention to performance is a transceiver that should really be able to support 10 Gbit/s over 30 m of InfiniBand cable, or 2x the distance of the 10GBASE-CX4 spec. This extra reach also enables the device to achieve respectable length connections over the thinner gauge wire that is often found in older wiring plants.
Low cost and flexibility were the other driving factors in this design. This flexibility is apparent when you discover that, thanks to programmable pin assignment, the MY3126 can serve as a cost-effective drop-in replacement for either XENPAK or X2/XPAK optical modules were the longer reach is not needed. Since they it fit into the same form factor as the optical modules, a line card can be easily configured to run either a copper or fiber connection.
If you need longer links than CX4 can provide, Mysticom also offers the MY3127, a transceiver that supports the LX4 for moving 10 Gbit/s of data across up to 300 m of multi-mode fiber. It also is pin-compatible with the MY3126: see the link to the data sheet for further details.
The MY3126 is sampling and is priced at $50 in high volume. Production will begin Q3 2004.
Data
Sheet MY3126
Data
Sheet MY3127