Electrical Redriver Modeling Solution from Agilent

Before the multigigabit era, chip-to-chip digital signals could propagate across an entire printed circuit board with little distortion. However, at today’s speeds, rising and falling edges degrade after travelling only a few inches on production board materials such as FR4. In digital applications, it is cost prohibitive to use high-frequency laminate board materials to solve this problem. Inserting a midchannel redriver circuit into the board provides a much more economical solution.

Up to now, simulation tools used to design nonlinear devices have used computationally expensive SPICE techniques such as Newton-Raphson iteration on modified nodal analysis of Kirchoff’s current law. With Agilent’s new redriver modeling solution, fast techniques based on bit-by-bit channel simulation and the IBIS AMI flow are now available for these applications. Unlike SPICE, these techniques include computationally efficient algorithms such as superposition. The techniques were developed by Agilent during a project with Maxim Corp.

Using a novel prestandard extension to the industry-standard IBIS AMI flow, SystemVue 2012 now offers model builders (integrated circuit vendors, for example) a tool to build redriver models. The models run in Agilent’s ADS software, the tool that IC buyers (makers of data center and telecommunications equipment, for example) use to design these chips into their systems.

“We’ve worked closely with Agilent to use SystemVue 2012 to develop prestandard AMI models of our MAX3997 10.3-Gbps Equalizer-Redriver, which our mutual customers can use,” said Mahbubul Bari, models engineer at Maxim Integrated. “The AMI models run much more quickly than SPICE models. This speed lets equipment manufacturers explore the design space. They can plug the model into an end-to-end simulation in ADS 2012 and come up with the optimum combination of transmitter/receiver settings, their channel design and the Maxim redriver settings.”

“It’s been a win-win-win collaboration to work with Maxim as lead customer on this project,” said Colin Warwick, product manager for high-speed digital design at Agilent EEsof EDA. “Maxim gets their redriver designed in quickly, Agilent tools become more valuable to mutual equipment-manufacturing customers, and those customers gain systems that meet performance specifications with low cost and fast time-to-market.”

Maxim and Agilent will submit a proposed enhancement to the IBIS Open Forum later this year with the intent to incorporate the new techniques into a future version of the IBIS standard. Doing so would allow redriver model portability across EDA tools that support this proposed enhancement.

Agilent’s SystemVue 2012 and Advanced Design System 2012 are available now. Pricing depends on the exact configuration desired.