Video Tutorial: What is Verilog-A

Video Tutorial: What is Verilog-A

Verilog-A is a behavioural modelling language for analog circuits from the Verilog Family. It is the subset of Verilog-AMS. Verilog-A HDL is derived from the IEEE 1364 Verilog HDL specification. The intent of Verilog-A HDL is to let designers of analog systems and integrated circuits create and use modules that encapsulate high-level behavioural descriptions as well as structural descriptions of systems and components.

Reference: 

[1] OVI Verilog-A LRM , 1996

[2] https://literature.cdn.keysight.com/litweb/pdf/ads2004a/pdf/verilogaref.pdf

[3] A New Approach to Compact Semiconductor device Modelling with Qucs Verilog-A analog module synthesis, M.E Brinson & V Kuznetsov, International Journal of Numnerical Mdelling, 2015

[4] https://github.com/cogenda/VA-BSIM48/blob/master/bsim4_release.va

[paper] Nanowire gate-all-around MOSFETs modeling

Cheng, He, Tiefeng Liu, Chao Zhang, Zhijia Yang, Zhifeng Liu, Kazuo Nakazato

and Zhipeng Zhang

Nanowire gate-all-around MOSFETs modeling:

ballistic transport incorporating the source-to-drain tunneling

Japanese Journal of Applied Physics (2020)

Accepted Manuscript online 5 June 2020

DOI: 10.35848/1347-4065/ab99db

Abstract: Incorporating the source-to-drain tunneling current valid in all operating regions, an analytical compact model is proposed for cylindrical ballistic GAA-nMOSFETs with ultra-short Silicon channel. From taking the DIBL effect into consideration, the potential distribution within the device channel has been modeled based upon a 2-D analysis in our previous work. In this study, by introducing a parabolic function when modeling the potential profile in the channel direction, we found out that the source-to-drain tunneling effect in the subthreshold region could be evaluated analytically by applying WKB approximation. Then, it is practical to estimate the drain current for all operating regions analytically with this compact model considering both the source-to-drain tunneling and thermionic transport. The resulting analytic compact model is tested against NEGF simulation using SILVACO, and good accuracy is demonstrated. Finally, we perform an NMOS inverter circuit simulation using HSPICE, introducing our model to it as a Verilog-A script.

Fig: Rough sketch of the potential energy profile along the channel and illustration of mechanisms governing the carrier transport in ballistic tunneling and thermionic modes.
(a) Representation of energy levels distribution along the z-direction at the channel center (r = 0).
(b) Schematics of confinement potential energy distribution along r-component at the barrier top (z = zMAX) in the cross section. The elementary charge stands for letter e. 

Acknowledgment: The authors would like to thank Prof. S. Uno for his support to this work. This work has been supported by the science and technology program of Liaoning, the major industrial projects (Grant No. 2019JH1/1010022

[paper] Compact Device Models for FinFET and Beyond

D. D. Lu, M. V. Dunga, A. M. Niknejad, C.Bing Hu, F.-X. Liang, W.-C. Hung, J. Lee, C.-H. Hsu
and M.-H. Chiang,

Compact device models for FinFET and beyond

ArXiv, vol. abs/2005.02580, 2020

Abstract - Compact device models play a significant role in connecting device technology and circuit design. BSIM-CMG and BSIM-IMG are industry standard compact models suited for the FinFET and UTBB technologies, respectively. Its surface potential based modeling framework and symmetry preserving properties make them suitable for both analog/RF and digital design. In the era of artificial intelligence / deep learning, compact models further enhanced our ability to explore RRAM and other NVM-based neuromorphic circuits. We have demonstrated simulation of RRAM neuromorphic circuits with Verilog-A based compact model at NCKU. Further abstraction with macromodels is performed to enable larger scale machine learning simulation.

Fig: Simulation of a novel floating - gate synaptic transistor. (a) Device structure with separate negative feedback gate (nfb) for programming and synaptic gate (sg) readout. (b) Equivalent circuit diagram for compact modeling 

Acknowledgements - The authors would like to express sincere gratitude to Chip Implementation Center (CIC), Hsinchu, Taiwan for providing SPICE simulation environment for RRAM simulations.

IEEE TED SI on Compact Modeling for Circuit Design

Special Issue on Compact Modeling for Circuit Design

Benjamin Iñiguez, Wladek Grabinski, Slobodan Mijalković, Kejun Xia, Andries J. Scholten, Yogesh Singh Chauhan, Ananda S. Roy, Sadayuki Yoshitomi, Kaikai Xu

in IEEE Transactions on Electron Devices, vol. 66, no. 1, Jan. 2019.

doi: 10.1109/TED.2018.2884284

Abstract: This Special Issue is dedicated to recent research in the field of compact modeling for circuit design. The topics included all device structures, provided it was demonstrated that the presented compact modeling solutions were implementable in circuit design tools. The last Special Issue addressing compact modeling of all types of semiconductor devices was published in 2006. Since then, new device structures, and with different materials, have emerged, and significant and successful research in compact advance device modeling has been done, as well in the application of compact models to circuit design. Therefore, a new Special Issue was needed that could include high-quality papers in these topics.

This Special Issue is dedicated to recent research in the field of compact modeling for circuit design. The topics included all device structures, provided it was demonstrated that the presented compact modeling solutions were implementable in circuit design tools. The last Special Issue addressing compact modeling of all types of semiconductor devices was published in 2006. Since then, new device structures, and with different materials, have emerged, and significant and successful research in compact advance device modeling has been done, as well in the application of compact models to circuit design. Therefore, a new Special Issue was needed that could include high-quality papers in these topics.

A total of 60 regular papers were submitted to this Special Issue, of which 21 were accepted. Besides, the Special Issue includes four invited papers. All papers, including the invited ones, were subjected to thorough peer review. A high number of reviewers have participated in this process. This has resulted in a Special Issue containing very high-quality papers.

The published papers target compact modeling aspects for a wide number of devices: several MOSFET structures, tunnel FETs, HEMTs, nanowire FETs, TMD FETs, TFTs, OLEDs, solar cells, photodiodes, and so on.Besides, different operation regimes and analyses are addressed: dc, RF, HV, ballistic regime, variability, reliability, aging, and so on.

The four invited papers also target different topics. The paper by C. C. McAndrew is focused on the successes and challenges of MOS compact models. S. Dongaonkar et al. address the opportunities and challenges of circuit design methodologies ranging from process corners to statistical circuit design. P. Zampardi et al. discuss the industrial view of III–V device compact modeling for circuit design. Finally, Madec et al. target a quite different and challenging environment for the modeling of biosensors, biosystems, and lab-on-chips.

I would like to thank the work done by the rest of the Editors of this Special Issue and also by all the reviewers who participated in this process. And of course, I want to thank all the authors for their interest in submitting papers to this Special Issue. Thanks to authors, reviewers, and editors, this high-quality Special Issue has been possible.

FOSDEM 2018 CAD and Open Hardware Devroom Call for Participation

(Also visible at https://www.ohwr.org/projects/ohr-meta/wiki/FOSDEM2018)

This is the call for participation in the FOSDEM 2018 devroom on Computer Aided Design (CAD) tools and Open Hardware, to be held on Saturday 3 February 2018 in Brussels, Belgium. We are looking for contributions under the form of talks and tutorials covering the following main topics:

• Printed Circuit Board (PCB) design tools (e.g. KiCad and gEDA)
• Analogue and digital simulators (e.g. ngspice, Qucs, Gnucap, Xyce,GHDL, Icarus and Verilator)
• Any other EDA tools such as high-level tools for digital hardware design (e.g. Migen) and HDL synthesis tools (e.g. Yosys)
• Field solvers such as openEMS
• Mechanical 2D and 3D CAD tools such as LibreCAD, FreeCAD, OpenSCAD andSolveSpace
• Open Hardware projects such as the Teres laptop and the lowRISC SoC
• Inter-project opportunities for collaboration

We hope to provide an opportunity for attendees to bring themselves up to date on the latest FOSS CAD and Open Hardware developments, share knowledge and identify opportunities to collaborate on development tasks. This devroom is an evolution of the EDA devroom we organised in 2015, 2016 and 2017.

The submission process: Please submit your proposals at

https://penta.fosdem.org/submission/FOSDEM18 before 1 December 2017.

If you already have a Pentabarf account (for example as a result of having submitted a proposal in the past), make sure you use it to log in and submit your proposal. Do not create a new account if you already have one. Please provide a bit of information about yourself under Person -> Description -> Abstract. When you submit your proposal (creating an "Event" in Pentabarf), make sure you choose the "CAD and Open Hardware Devroom" in the track drop-down menu. Otherwise your proposal might go unnoticed. Fill in at least a title and abstract for the proposed talk and a suggested duration. Bear in mind that a lot of the value in these meetings comes from the discussions, so please be reasonable regarding the duration of the talk.

Important dates

• 1 December 2017: deadline for submission of proposals
• 8 December 2017: announcement of final schedule
• 3 February 2018: devroom day

Recordings: The FOSDEM organisers hope to be able to live-stream and record all the talks. The recordings will be published under the same licence as all FOSDEM content (CC-BY). Only presentations will be recorded, not informal discussions and whatever happens during the lunch break. By agreeing to present at FOSDEM, you automatically give permission to be recorded. The organisers will agree to make exceptions but only for exceptional and well-reasoned cases.

Mailing list: Feel free to subscribe to the mailing list of the CAD and Open Hardware devroom to submit ideas, ask questions and generally discuss about the event:

https://lists.fosdem.org/listinfo/open-hardware-devroom

Spread the word!

[paper] Accurate diode behavioral model with reverse recovery

Stanislav Banáš^a,b, Jan Divína^b, Josef Dobeš^b, Václav Paňko^a

^aON Semiconductor, SCG Czech Design Center, Department of Design System Technology, 1. maje 2594, 756 61 Roznov pod Radhostem, Czech Republic

^bCzech Technical University in Prague, Faculty of Electrical Engineering, Department of Radioelectronics, Technicka 2, 166 27 Prague 6, Czech Republic

Solid-State Electronics

Volume 139, January 2018, Pages 31–38

https://doi.org/10.1016/j.sse.2017.10.034

Highlights:

• The complex robust time and area scalable Verilog-A model of diode containing reverse recovery effect has been developed.
• Due to implemented reverse recovery effect the model is useful especially for high-speed or high-voltage power devices.
• The model can be used as stand-alone 2-terminal diode or as a parasitic p-n junction of more complex lumped macro-model.
• Two methods of model parameter extraction or model validation have been demonstrated.

ABSTRACT: This paper deals with the comprehensive behavioral model of p-n junction diode containing reverse recovery effect, applicable to all standard SPICE simulators supporting Verilog-A language. The model has been successfully used in several production designs, which require its full complexity, robustness and set of tuning parameters comparable with standard compact SPICE diode model. The model is like standard compact model scalable with area and temperature and can be used as a stand-alone diode or as a part of more complex device macro-model, e.g. LDMOS, JFET, bipolar transistor. The paper briefly presents the state of the art followed by the chapter describing the model development and achieved solutions. During precise model verification some of them were found non-robust or poorly converging and replaced by more robust solutions, demonstrated in the paper. The measurement results of different technologies and different devices compared with a simulation using the new behavioral model are presented as the model validation. The comparison of model validation in time and frequency domains demonstrates that the implemented reverse recovery effect with correctly extracted parameters improves the model simulation results not only in switching from ON to OFF state, which is often published, but also its impedance/admittance frequency dependency in GHz range. Finally the model parameter extraction and the comparison with SPICE compact models containing reverse recovery effect is presented [read more...]

FIG: Solving the recursive calculation of reverse recovery charge

VALint: the NEEDS Verilog-A Checker

By Xufeng Wang¹, Geoffrey Coram², Colin McAndrew³

1. Purdue University 2. Analog Devices, Inc. 3. Freescale Semiconductor

Version 1.0.0 - published on 31 Mar 2017

doi:10.4231/D3HX15S0V

Abstract: VALint is the NEEDS created, automatic Verilog-A code checker. Its purpose is to check the quality of the Verilog-A code and provide the author feedback if bad practices, common mistakes, pitfalls, or inefficiencies are found. This VALint is published as a standalone tool for the compact model community. It is also built-in as an integrated part of the NEEDS publishing platform [read more...]

[paper] Well-Posed Device Models for Electrical Circuit Simulation

Well-Posed Device Models for Electrical CircuitSimulation
A Guide to Creating Robust Device Models
A. Gokcen Mahmutoglu, Tianshi Wang, Archit Gupta and Jaijeet Roychowdhury
March 25, 2017

Synopsis: This document provides guidelines for creating computational device models that work well in simulation. We build our discussion around the mathematical notion of “well-posedness”. We show that the requirements for a model to be well-posed stem from the internal working mechanisms of simulators. Therefore, our main aim is to provide insight into the numerical procedures used by simulators in order to help model developers avoid ill-posedness issues. We start our discussion with an example that shows how an ill-posed Verilog-A model can produce different simulation results in different simulators. We then provide a step-by-step simulation case study. In this case study, we illustrate the role of device models in simulations by examining the steps a simulator goes through, from taking a netlist as input to producing a simulation result as output. Finally, we distill our discussion in a functional definition of a well-posed model. As an extension to our theoretical discussion, we also provide practical guidelines that should be followed by Verilog-A models in order to avoid ill-posedness issues [read more...]

This document is published as a part of the Nano-Engineered Electronic Device Simulation (NEEDS) initiative. NEEDS is an NSF-funded initiative whose charter includes the development of tools and techniques for the production of high-quality device models¹:
NEEDS has a vision for a new era of electronics that couples the power of billion-transistor CMOS technology with the new capabilities of emerging nano-devices and a charter to create high-quality models and a complete development environment that enables a community of compact model developers.

NEEDS Team: Purdue, MIT, UC Berkeley, and Stanford.”

¹For more information about NEEDS please visit https://nanohub.org/groups/needs/.

FOSDEM 2017 EDA Devroom Call for Participation

FOSDEM 2017 Electronic Design Automation Devroom
Call for Participation

This is the call for participation in the FOSDEM 2017 devroom on Free/Open Source Software (FOSS) Electronic Design Automation (EDA) tools, to be held on Sunday 5 February 2017 in Brussels, Belgium. We are looking for contributions under the form of talks and tutorials covering the following main topics:

• Printed Circuit Board (PCB) design tools (e.g. KiCad and gEDA)
• Analogue and digital simulators (e.g. ngspice, Qucs, Gnucap, Xyce, GHDL, Icarus and Verilator)
• Any other EDA tools such as high-level tools for digital hardware design (e.g. Migen) and HDL synthesis tools (e.g.Yosys)
• Inter-project opportunities for collaboration

We hope to provide an opportunity for attendees to bring themselves up to date on the latest FOSS EDA developments, share knowledge and identify opportunities to collaborate on development tasks. Have a look at last year's event for a taste of what the EDA devroom is about.

The submission process
Please submit your proposals at 

https://penta.fosdem.org/submission/FOSDEM17 

before 1 December 2016.

If you already have a Pentabarf account (for example as a result of having submitted a proposal in the past), make sure you use it to log in and submit your proposal. Do not create a new account if you already have one. Please provide a bit of information about yourself under Person -> Description -> Abstract. When you submit your proposal (creating an "Event" in Pentabarf), make sure you choose the "Electronic Design Automation (EDA) devroom" in the track drop-down menu. Otherwise your proposal might go unnoticed. Fill in at least a title and abstract for the proposed talk and a suggested duration. Bear in mind that a lot of the value in these meetings comes from the discussions, so please be reasonable regarding the duration of the talk.

Important dates

• 1 December 2016: deadline for submission of proposals
• 11 December 2016: announcement of final schedule
• 5 February 2017: devroom day

Recordings
The FOSDEM organisers hope to be able to live-stream and record all the talks. The recordings will be published under the same licence as all FOSDEM content (CC-BY). Only presentations will be recorded, not informal discussions and whatever happens during the lunch break. By agreeing to present at FOSDEM, you automatically give permission to be recorded. The organisers will agree to make exceptions but only for exceptional and well-reasoned cases.
Mailing list

Feel free to subscribe to the mailing list of the EDA devroom to submit ideas, ask questions and generally discuss about the event.

Spread the word!
This is the third EDA devroom at FOSDEM. The first two were very well received. Let's make sure as many projects and developers as possible are present. Thanks!

[paper] Well-Posed Models of Memristive Devices

Well-Posed Models of Memristive Devices

Tianshi Wang, Jaijeet Roychowdhury

(Submitted on 15 May 2016)

Existing compact models for memristive devices (including RRAM and CBRAM) all suffer from issues related to mathematical ill-posedness and/or improper implementation. This limits their value for simulation and design and in some cases, results in qualitatively unphysical predictions. We identify the causes of ill-posedness in these models. We then show how memristive devices in general can be modelled using only continuous/smooth primitives in such a way that they always respect physical bounds for filament length and also feature well-defined and correct DC behaviour. We show how to express these models properly in languages like Verilog-A and ModSpec (MATLAB). We apply these methods to correct previously published RRAM and memristor models and make them well posed. The result is a collection of memristor models that may be dubbed "simulation-ready", i.e., that feature the right physical characteristics and are suitable for robust and consistent simulation in DC, AC, transient, etc., analyses. We provide implementations of these models in both ModSpec/MATLAB and Verilog-A.

Subjects: Emerging Technologies (cs.ET); Computational Engineering, Finance, and Science (cs.CE)
Cite as: arXiv:1605.04897 [cs.ET]
(or arXiv:1605.04897v1 [cs.ET] for this version)

FOSDEM 2016 EDA Devroom

FOSDEM 2016: EDA Devroom

Room: AW1.121 

Saturday, 30 January 2016

Software developers have a much easier time sharing their developments than hardware designers. When you put a piece of code on the Web, you don't ask yourself if others will have the freedom and resources to access a text editor to look at it and modify it, or a compiler or interpreter to have the code do something useful. The landscape for hardware designs is more complicated. The dominant design and simulation tools are proprietary, and there is not even a de-facto proprietary standard format to share designs. The Electronic Design Automation (EDA) Devroom looks at recent progress in Free CAD/EDA Tools for hardware design and simulation, and serves as a meeting place for discussion about future collaborations and FOSS developments. Come and see how some of these tools are actually catching up, and sometimes even more, in terms of features and quality.

[EDA Devroom Detailed Agenda]

NEEDS Berkeley Workshop 2016

Modelling using Verilog-A in MAPP: A Hands-On Workshop

8 AM - 6 PM

Thursday, Feb 4, 2016

University of California, Berkeley

Hughes Room, 400 Cory Hall

Berkeley, CA 94720

---

Berkeley's Model and Algorithm Prototyping Platform (MAPP) is a MATLAB-based platform that provides a complete environment for developing, testing, experimentally validating, and inserting compact models in open source simulation platforms. It is also useful for prototyping new simulation algorithms.

This hands-on workshop will focus on the newly developed Verilog-A to ModSpec device model translator for MAPP, dubbed VAPP (Verilog-A Parser and Processor). The goal of the workshop is to illustrate how VAPP/MAPP facilitates the development of simulation ready compact models. An overview of MAPP's multi-physics modelling and simulation capabilities will also be provided. A hands-on refresher on MAPP will be provided for those who have no prior experience with it.

Please bring your laptop (running linux, OSX or Windows). It would be very helpful if you already have MATLAB installed and running on your laptop; otherwise you may need to access the hands-on components through the web.

For more information about MAPP, see: https://nanohub.org/groups/needs/mapp

---

Travel support will be available for NEEDS students. Please try to share a room, and ask your advisor to e-mail Mark Lundstrom at lundstro@purdue.edu for travel support.

For other questions, please contact Vicki Johnson at vicki@purdue.edu

New i-MOS Release

http://i-mos.org/
A new release of the interactive Modeling and On-line Simulation Platform (i-MOS), version 201401 is available online. In this release, the i-MOS team launched several new services, as well as improved some modules in previous versions. A list of these new features follows:

• Evaluative support for BSIM3 with newly designed interfaces;
• A collection of model parameter cards for your applications;
• A newly implemented double-gate/FinFET model SDDGM; 
• Parameter searching function for all the device models;
• Integrated text editor for composing netlists in circuit simulations;
• Easier entry for your posting of news and events, etc.

For more details and an updated user manual, please see http://i-mos.org

Other related compact/SPICE modeling events and news are listed at:
http://i-mos.org/imos/resources

CMC @ Si2

The CMC as a member of the Si2 will continue its basic goal of examining, promoting and standardizing SPICE modeling efforts based upon business needs. CMC (see its Member List)  encourages developers to dwell on current and near-term problems that will advance compact modeling. They will continue to provide industry resources and funding for monitoring/mentoring compact model development.

[read more: CMC Presentation at DAC]

13. ITG/GMM-Fachtagung Analog 2013

13. ITG/GMM-Fachtagung Analog 2013
4. - 6. März in Aachen
Entwicklung von Analogschaltungen mit CAE-Methoden

Die Registrierung ist eröffnet!

Call For Papers:

Programm und Anmeldeformular:

QucsStudio 1.4.2

A new version of QucsStudio has just been released for general use. The latest version is mainly  bug fixes but does contain a number of new/improved features. A list of the changes are given below:

• some corrections in help system
• component names in noise contribution analysis with subcircuit prefix
• reduced time step warnings in transient analysis
• bugfix: differential voltages in equations
• in equations: allow suffix in node names
• bugfix: directory MinGW\mingw32\bin\ exists again
• bugfix: crash in diagram dialog if clicking on empty variable area
• new component: photodiode
• new equation function: stoa()
• bugfix: spaces allowed between function name and "("
• added InP permittivity in property list
• bugfix: correct text in C++ symbol string
• error message for wrong index in equation variables

This is likely to be one of the last releases in the QucsStudio 1.4 series.  Work has started on QucsStudio series 2.0.0.  QucsStudio 2.0.0 is expected to offer users significant improvements in simulation and modelling capabilities.  The first of the new releases will coincide with the tenth anniversary of the first release of Qucs next year.

QucsStudio can be downloaded from the QucsStudio homepage at http://www.mydarc.de/DD6UM/QucsStudio/qucsstudio.html

Contact: Mike Brinson