Tag Archive AMS

ByAdele Hars

Silicon Valley FD-SOI 2018 Training Day is April 27th – Don’t Miss It!

Following the immense success of last years FD-SOI training day in Silicon Valley, the SOI Consortium has another one planned for the end of April this year. If you want to start learning how to leverage FD-SOI in your chip designs, this is a great place to start. Click here for information on how to sign up.

ST Fellow Dr. Andreia Cathelin has put together another great line-up. World renowned professors and experts from industry will deliver a series of four training sections of 1.5 hours each, focused on energy efficient and low-power, low-voltage design techniques for analog, RF, high-speed, mmW and mixed-signal design.

You’ll learn about design techniques that take full advantage of the unique features of FD-SOI, including body biasing capabilities that further enhance the excellent analog/RF performances of these devices.

Each section of this training day will take you through concrete design examples that illustrate new implementation techniques enabled by FD-SOI technologies at the 28nm and 22nm nodes – and beyond.

The design examples will cover basic building blocks through SoC implementations. A global Q&A session will close the day.

Here’s a little more info on how the day will unfold. Click on the slides to see them in full screen.

Morning sessions

FDSOI-specific design techniques for analog, RF and mmW applicationsAndreia Cathelin, Fellow, STMicroelectronics

Quick preview from Andreia Cathelin’s FD-SOI training session (Courtesy: STMicroelectronics, SOI Consortium)

Andreia Cathelin is ST’s key design scientist for all advanced CMOS technologies, and is arguably the world’s leading expert on leveraging FD-SOI in high-performance, low-power RF/AMS SoCs. Her course will first present a very short overview of the major analog and RF technology features of 28nm FDSOI technology. Then the focus moves to the benefits of FD-SOI technology for analog/RF and millimeter-wave circuits. She’ll give design examples such as analog low-pass filters, inverter-based analog amplifiers and 30GHz and 60GHz Power Amplifiers, as well as mmW oscillators. There will be particular focus on the advantages of body biasing and special design techniques offering state-of-the-art performance.

Circuit Design Techniques in 22nm FD-SOI for 5G 28GHz ApplicationsFrank Zhang, Principal Member of Technical Staff, GlobalFoundries

Quick preview from Frank Zhang’s FD-SOI training session (Courtesy: GlobalFoundries, SOI Consortium)

Frank Zhang has designed chips using GF’s 22nm FD-SOI (22FDX) process for WLAN, 5G cellular and automotive radar applications. His course will focus on how to take advantages of FD-SOI’s high-frequency performance at relatively low-current density to design high performance RF/mmWave circuits. Examples circuits include a 28GHz LNA, a 28GHz PA and an RF switch for 5G applications. The FD-SOI advantages such as low capacitance, high breakdown voltage and high-output impedance will be exploited in these design examples. This course will also discuss how to extend these techniques to applications at higher frequencies and/or higher current densities that are subject to extreme temperatures and EM requirements.

Afternoon sessions

Energy-Efficient Design in FDSOIBora Nikolic, Professor, UC Berkeley

Quick preview from Bora Nikolić’s FD-SOI training session (Courtesy: UC Berkeley, SOI Consortium)

Borivoje (“Bora”) Nikolić is known as one of the world’s top experts in body-biasing for digital logic (he and his team have designed more than ten chips in ST’s 28nm FD-SOI.) If you missed it, his team’s RISC-V chip was cited as one of Dr. Cathelin’s “Outstanding 28nm FD-SOI Chips Taped Out Through CMP” – read more about that here. His talk at the training day will present options for energy-efficient mixed-signal and digital design in FD-SOI technologies. He’ll explain how to generate body bias and use it to improve efficiency, with examples in RF and baseband building blocks, temperature sensors, data converters and voltage regulators. The techniques will be presented in the context of UC Berkeley’s latest RISC-V-based SoC, designed to operate in a very wide voltage range using 28nm FD-SOI.

mm-Wave and Fiber-Optics Design in FD-SOI CMOS Technologies – Sorin Voinigescu, Professor, University of Toronto

Quick preview from Sorin Voinigescu’s FD-SOI training session (Courtesy: U. Toronto, SOI Consortium)

Sorin Voinigescu is a world renowned expert on millimeter-wave and 100+Gb/s ICs and atomic-scale semiconductor device technologies. His lecture will cover the main features of FD-SOI CMOS technology and how to efficiently use its unique features and suitable circuit topologies for mm-wave and broadband SoCs. He’ll begin with an overview of the impact of the back-gate bias and temperature on the measured I-V, transconductance, fT, and fMAX characteristics. Then he’ll compare the maximum available gain, MAG, of FDSOI MOSFETs with those of planar bulk CMOS and SiGe BiCMOS transistors through measurements up to 325 GHz. Next, he’ll provide biasing, sizing and step-by-step design examples for VCO, doubler, switches, PA, large swing optical modulator drivers and quasi-CML circuit topologies and layouts that make efficient use of the back-gate bias to overcome the limitations associated with the low breakdown voltage of 20nm and 12nm FD-SOI CMOS technologies.

Sign Up Now!

With over 100 attendees filling every chair in the auditorium, last year’s training day was sold out. Although it was in Silicon Valley, people actually flew in from all over the world to be there. During the Q&A at the end, most everyone prefaced their questions by saying, “Thank you. I really learned a lot today.”

2018 will be no different – except that it’s sure to sell out even faster. Please note, though, that this is not a free event, so only the attendees will get copies of the slide decks.

Here’s key info you need to sign up. See you there!

What: SOI Consortium’s FD-SOI Training Day

When: 27 April 2018, 7:30am – 5pm.

Where: Crowne Plaza San Jose, Milpitas CA (parking is free)

Registration fee: US $485.00 (includes training book, breakfast, box lunch and refreshments during breaks)

How to sign up: Click here to go directly to the registration site.

ByAdele Hars

Body Biasing: It’s Not an Obligation, It’s an Opportunity. And Other Take-Aways from the FD-SOI Design Tutorial Day.

Over a hundred chip designers packed the room for the SOI Consortium’s recent FD-SOI Design Techniques Tutorial Day. Five professors and scientists from top institutions covered design techniques with real examples in digital, mixed-signal, analog, RF, mmW and ULV memory.

Although it was in Silicon Valley, people actually flew in from all over the world to be there. During the Q&A at the end, most everyone prefaced their questions by saying, “Thank you. I really learned a lot today.”

Many of the questions pertained to body biasing, which prompted STMicroelectronics Fellow and Professor Andreia Cathelin to state what may well have been the take-away of the day. “Body biasing is not an obligation,” she said. “It’s an opportunity.”

Q& A with the professors at the end of the FD-SOI Tutorial day. (Courtesy: SOI Consortium)

The tutorial, sponsored by both Samsung and GlobalFoundries, was hosted by Samsung at their San Jose headquarters.  But as this was a paying event, the presentations are only available to those who attended.  Having had the good fortune to attend, I can give you a quick recap of some of the highlights.

Analog, Mixed-Signal and mmW Design: The Overview

Professor Cathelin set the stage with a basic overview of FD-SOI design for analog, mixed-signal and mmW.

FD-SOI is a perfect match for the many up and coming SOCs that are often half analog and/or RF and mmW.  She explained how FD-SOI makes the analog designer’s life much easier (no small feat, since analog can seem rather like blackbox magic to those on the digital side).  FD-SOI improves: performance (even at high frequencies), noise, short device efficiency and brings in a new very efficient transistor knob through the Vt (threshold voltage) tuning range. She also explained and gave numerous real examples implemented in ST’s 28FDSOI on how:

  • forward body bias (FBB) can be used as a Vt tuning knob, giving the designer a very large Vt tuning range, both for analog/RF and mmW designs;
  • the improved analog performance gives you lower power consumption;
  • transistors can operate with decent design margins at L>Lmin.

For mmW design, the transistor should operate at Lmin, and hence you get excellence performance in terms of both transition frequency (Ft – set by the technology node) and maximum frequency (Fmax – what the designer can really get in the gain vs. speed trade-off). This can be conjugated with the fact that the back-end of line, despite the very fine nm node, takes advantage of the SOI features and brings in very decent quality factors.

For mixed-signal/high-speed design, she showed how and why FD-SOI gives you improved variability, a fantastic switch performance, and reduced parasitic capacitance. All these permit state of the art results in high-speed data converters, or, for example, lower frequency implementations which do not need any specific calibration for best in class linearity and ENOB (effective number of bits).

She also presented details on the CEA-Leti electrical models which are now the reference stand point (Leti-UTSOI2) for any FDSOI technology, and are implemented in several industrial Design Kits such those from ST.

RF, mmW and Broadband Fiber-Optic SOCs

Next on tap was a very lively talk with almost 60 slides by Professor Sorin Voinigescu of U. Toronto.  He focused on how to use the main features of FD-SOI for efficient design of RF, mm-wave and broadband fiber-optic SOCs.  We’re talking high-speed/high-frequency here, and he had real examples of chips fabbed in ST’s 28FDSOI and some simulated in GlobalFoundries’ 22FDX technology.

Last slide from Professor Voinigescu FD-SOI tutorial. (Courtesy: U.Toronto, SOI Consortium)

He examined layout issues and gave measurement tips and tricks, noting that there are a lot of things you can do in FD-SOI that you can’t do in bulk.  It’s also easier to get high linearity in FD-SOI – yet another reason that he really likes it.  Plus he sees it as competitive in terms of scaling even past 7nm.

ULV Memories

Professor Joachim Rodrigues of Lund University in Sweden (the largest university in Scandinavia) talked about Design Strategies for ULV memories in 28nm FD-SOI (ST’s FD-SOI technology). Noting that SRAMs eat a lot of area in an SOC, he first proposed a standard cell-based memory (SCM) in 28nm FD-SOI that cut memory area by 35% and reduced leakage by 70%.

Professor Joachim Rodrigues of Lund University presenting at the 2017 FD-SOI Design Techniques Tutorial Day in Silicon Valley (Courtesy: Lund U., SOI Consortium)

He then talked about other chips he and his team have presented at the world’s top chip conferences, including an ultra-low voltage (ULV) SRAM.  For that chip they lay claim to having the best write performance in ULV in sub-65nm (15MHz at 240mV), and the  best performing read capability across all technologies (30MHz at 240mV). In each case, he explained the fundamental design considerations, concepts and trade-offs.

Berkeley: 10 FD-SOI Chips – and Still Counting!

Professor Borivoje “Bora” Nikolic of UC Berkeley is an expert in body-biasing for digital logic. He and his team have designed ten chips in ST’s 28nm FD-SOI, and they’re now working on their 8th generation of energy-efficient SOCs. During his 90-slide (!) tutorial, Energy-Efficient Processors in 28nm FDSOI, he covered: digital logic (including implementation and adaptive tuning of cores for optimal energy efficiency); SRAM and caches (design scenarios and results compared to bulk); supply (generating, switching and analog assists); back bias (how it’s generated and how to use it). He finished with (60 slides of!) design examples and the results they got for power (including adaptive voltage scaling) and performance. He said to be on the lookout for upcoming publications on (even more!) chips, as well as new work on 22nm designs.

A page from Professor Nikolic’s tutorial on FD-SOI design for digital logic. (Courtesy: UC Berkeley, SOI Consortium)

Pushing the Mixed-signal Envelope

Even if you don’t know anything about mixed-signal design, you can walk away from an hour-long lecture by Professor Boris Murmann of Stanford with a good understanding of what it’s all about. In his talk, Pushing the Envelope in Mixed-Signal Design Using FD-SOI, he explained how a mixed-signal person thinks about FD-SOI, and how the different metrics and sweetspots vary depending on what you’re working on.  From there it was the deep dive, as he got into the heart of his talk: simulated transition frequency vs. gm/lD. He explained that while some things might seem counter intuitive (like long channels are more efficient for very low Ft requirements), it’s all related to electrostatics. It’s not yet well explained in the literature, he said, but it should be a big deal.  And he explained why with FD-SOI, you don’t have to design for the worst case. He then talked about where he sees things going – he sees a very bright future indeed for FD-SOI and analog as computing moves into very low-power neural networks. In the end, he said, it all boils down to the FD-SOI performance benefits with respect to better gate control. This translates into “significant improvements” for many mixed-signal/RF building blocks.

Professor Boris Murmann talks about FD-SOI for mixed-signal. (Courtesy: Stanford, SOI Consortium)

All in all, it was a really terrific day. BTW, this tutorial day followed a full-day FD-SOI Symposium in Silicon Valley. Click here to read about that.