No magic bullet for crosstalk
January 31, 2012 // Dylan McGrath
There is no perfect solution to the problem of crosstalk in modern communications ICs, an increasing concern as chip designers push devices into the realm of 28-gigabits per second and beyond, according to a panel of experts at DesignCon 2012 here Monday (January 30).
Crosstalk—unintended interference of communication channels—can wreak havoc on a comms IC. But panelists, including representatives from test and measurement equipment vendors Tektronix Inc., Agilent Technologies Inc., and LeCroy Corp., — acknowledged that there are currently no tools that enable designers to adequately measure the effects of various types of crosstalk, thus preventing them from modifications that mitigate the problem.
To make matters worse, panelists said, there is a major disconnect between what communications standards such as PCI Express specify and what is actually needed to build chips that send and receive at cutting-edge speeds. "There is a fundamental difference between a silicon implementation and the reference equalizers you see in these emerging standards such as PCI Express," said Mark Marlett, director of engineering responsible for serdes development at IP vendor Analog Bits Inc.
While there is no fail safe solution for measuring the effects of cross talk on a chip, Mike Peng Li, principal architect and distinguished engineer at programmable logic vendor Altera Corp., said the best existing solution is decision feedback equalizer (DFE), a type of circuit that can be inserted into a design to minimize crosstalk. "The DFE is the best medicine we have," Li said.
DFE is "a medicine that doesn't have the side effect of amplifying noise," said Martin Miller, chief scientist at LeCroy.
Panelists generally agreed with Li that DFE represents the best hope currently. But the method has its limitations. DFE has a problem with "avalanching" errors, said Ransom Stephens, a tech consultant and writer who served as the panel's moderator. "When it stumbles, it falls," Stephens said.
At one point , Stephens chided test and measurements on the panel, joking that they were working on solutions for the problem of crosstalk that they were reluctant to mention publicly. "There are proprietary solutions being developed," Stephens said after the panel concluded.
"We do have some ideas and some concepts on how to measure crosstalk and what we can do about it," said Pavel Zivny, a domain expert for serial data at Tektronix.
Panelists admitted that the ultimate solution to the crosstalk problem is a move to channels based on silicon photonics. Zivny joked at one point that audience members should drain their children's college funds to invest in any company involved in silicon photonics.
Li said the fundamental limit for comms chips using current CMOS technology is probably around 50- to 60-Gbps. After that, he said, some type of photonics scheme must be implemented for comms chips to push the envelope further. Li lamented the fact that only a very few companies, chiefly Intel Corp., and IBM Corp., are doing the fundamental research needed to move silicon photonics onto chips, but he predicted that "gradual changes" over the next three to four years would move that technology into semiconductors, much sooner than many observers think that it will happen.
Floating surge stopper provides unlimited overvoltage protection
May 17, 2013
Protecting sensitive electronic circuitry from voltage transients is an essential part of any system be it automotive, industrial, ...
Altera to integrate Enpirion power interfaces into its FPGAs
Automation CAN group plans permanent interoperability test capability
Opening up new user-interaction scenarios with Time-of-Flight measurements
Goepel electronic initiates Cooperation Network with EMS companies
The number of charging stations for electrical vehicles is expected to soar by 20220, study says
May 17, 2013
The number of electric vehicle charging stations is set to soar globally by 2020, supporting a shift in driving away from ...
In automotive lighting, LEDs still lacks of horsepower, study says
Ultra-low-power SoC supports world's smallest Bluetooth location stickers
Imec and Renesas collaborate on ultra-low power short range radios
InterviewWireless control drives Atmel in Europe
Atmel's recent acquisition of Osmo Devices with a WiFi Direct design center in Cambridge and some key microcontroller launches has seen the company focus heavily on wireless control in Europe says Jörg ...
Filter WizardCheck out the Filter Wizard Series of articles by Filter Guru Kendall Castor-Perry which provide invaluable practical Analog Design guidelines.
Linear video channel
READER OFFERRead more
The development platform for i.MX 6Quad from element14 (built to the Freescale SABRE Lite design) is an evaluation platform featuring the powerful i.MX 6Q, a multimedia application processor with Quad ARM Cortex-A9 cores at 1.2 GHz from Freescale Semiconductor.
This month, Freescale and element14 are giving away five such platforms, worth £128.06 each, for EETimes Europe's readers to win. The platform helps evaluate the rich set of peripherals and includes a 10/100/Gb Ethernet port, SATA-II, HDMI v1.4, LVDS, parallel RGB interface, touch screen interface, analog headphone/microphone, micro TF and SD card interface, USB, serial port, JTAG, camera interface, and input keys for Android.
And the winners are...
In our previous reader offer, Pico Technology was giving away one of its recently launched PicoScope 3207B, a 2-channel USB 3.0 oscilloscope worth 1451 Euros. Lucky winner Mr L. Sanchez-Gonzalez from Spain should be receiving his PicoScope 3207B soon. Let's wish them some interesting findings with his projects.
December 15, 2011 | Texas instruments | 222901974
Unique Ser/Des technology supports encrypted video and audio content with full duplex bi-directional control channel over a single wire interface.