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Interview with Randy Wolff, New IBIS Open Forum Chair

By Scott Schlachter - 2019-08-25

Recently the IBIS [I/O Buffer Information Specification] Open Forum nominated and voted in Micron's principal signal integrity engineer, Randy Wolff, as its new chair. This is a great accomplishment and opportunity, for both Randy and Micron, to provide leadership for such an influential discipline. I had the chance to sit down with Randy, ask him some questions, and learn more from him about the IBIS Open Forum and his role.

Scott: Hi Randy, I’ve been familiar with IBIS for a long time, but for those who are unfamiliar, could you describe what the IBIS Open Forum is?

Randy: The IBIS Open Forum is a standards group that’s focused on signal and power integrity modeling and simulation. It exists primarily to maintain and develop the IBIS spec [specification] and other related specs like Touchstone. I really like that IBIS brings together a broad community of engineers from different companies, including IC [integrated circuit] vendors, EDA [electronic design automation] software providers, and systems designers. IBIS models have become ubiquitous in the SI [signal integrity] community because they’ve provided a reliable way for SI engineers to run fast simulations and sign off their system designs. Model providers like us here at Micron like IBIS models because we can protect our IP [intellectual property] and bring value to our customers. There’s information on the IBIS website for people to check out.

Scott: How long have you participated in this forum and what’s it been like?

Randy: I think I called into my first Open Forum teleconference in late 2000. I became IBIS secretary in 2003 and continued serving in that position until this year. Being on the IBIS board and working in the task groups to represent Micron’s technical interests in IBIS have been great experiences. There are a lot of people in IBIS who are passionate about the specification and dedicated to the success of IBIS and its usefulness to the SI community. We have heated discussions on occasion, but we try to work toward consensus in our solutions. We have most meetings by phone, so I’ve really enjoyed the times I’ve attended in-person meetings and matched faces to the voices I’m so used to hearing.

Scott: Which audiences do you think the IBIS Open Forum interacts with or addresses?

Randy: People involved in IBIS tend to fall into three main categories: model makers, model users, and EDA software providers. All of us are involved in signal and power integrity in some way, like system PCB [printed circuit board] design, package design, I/O buffer design, or simulation software design. IBIS is an integral part of the SI/PI [power integrity] ecosystem.


Scott: As the new chair, what skills, experience or unique perspective do you bring to the position?

Randy: My involvement with IBIS has been as a model provider and a model user. Working in the signal integrity group at Micron has exposed me to the needs of the SI engineer for high-quality models, well-designed EDA software that properly integrates IBIS models into the simulation flow, and good documentation. I think my perspective from my time at Micron positions me to understand the needs of the IBIS community. I have a good relationship with all the IBIS member companies too.

Scott: What challenges do you see facing modeling moving forward?

Randy: As interface speeds continue increasing, it gets more and more challenging to meet timing budgets and maintain acceptable SI and PI. My exposure is mostly to memory channels, where single-ended signaling is being pushed to 16+ Gbps in graphics memories — amazing if you ask me. There are so many challenges in modeling these interfaces when trying to account for all the channel impairments, equalization, and jitter contributions, including nonlinear and time-variant sources. Modeling clock-jitter contributions in IBIS-AMI [Algorithmic Modeling Interface] simulation workflows is a new challenge too. So is robust power delivery network design in terms of getting all the dynamic current demand waveforms you might need to properly analyze your PDN [power delivery network] design.

Scott: How does Micron help solve these problems?

Randy: I think Micron plays an integral role in helping identify the problems and working with all the other players in the IBIS ecosystem to come up with innovative solutions. We have some great technical talent in our company, and we must continue to work closely with the other IC vendors and all the EDA software companies to bring solutions to the marketplace.

Scott: Are there specific products or types of products that will benefit from your leadership in the IBIS Open Forum?

Randy: All of our products benefit from our involvement in IBIS. We’re focused on improving IBIS support for stacked die packages and DIMM [dual in-line memory module] models. We’re also working on improvements to IBIS-AMI modeling for new technologies using equalization such as DDR5, LPDDR5, and GDDR6. Part of my role will be to support proposed changes to IBIS for technologies we may not directly design, like next-gen PCIe.


Scott: What excites you about being the chair of the forum?

Randy: I’m really honored to be chair of the IBIS Open Forum and grateful for Micron’s support in this new role. It’s an exciting time to be involved in signal integrity. We have lots of challenges ahead but really excellent technical leadership here and good partners to work with in the IBIS community to continue solving problems and enabling new technologies.

Scott: Thanks for your time, Randy. What an honor for you and a great example of a technical leadership role for Micron.

Scott Schlachter