1st mos-ak international meeting - san francisco dec. 13th, 2008 compact model standardization – a...

1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

Compact model standardization – a GNU

perspective

Paolo Nenzi - CNR-INFM

Wladek Grabinski - GMC


Standard

What a standard is ? a documented agreement containing technical

specifications or other precise criteria to be used consistently as rules, guidelines, or definitions of characteristics, to ensure that materials, products, processes, and services are fit for their purpose.


Perspectives

Actual: The standard is the

compact model. Not all candidates for a

given technology are standardized.

GNU: The standard specifies

the rules to develop compact models.

The standard must be open.

The compact model must be free.


Consequences

Actual perspective The models are

standards. First class models

(BSIM, PSP) and second class models.

Long delays in model release in circuit simulators.

Lack of models for new or less common devices.

GNU perspective Models conform to an

open standard. All models are equals. Faster development and

acceptance. Development of model

for frontier devices (MEMS, etc.)


An Open Standard

The GNU compact model standard should be open (as defined by OSI): No intentional secrets. Availability (publicly available, royalty-free). Based on royalty free patents. No agreements (NDAs, etc.) to deploy conforming

implementations. No dependencies on non open technology

(according to this definitions)


A free model

The compact models should give the 4 freedoms: The freedom to run the model, for any purpose. The freedom to study how the model works, and

adapt it to your needs. The freedom to redistribute copies so you can

help your neighbor. The freedom to improve the model, and release

the improvements to the public, so that the whole community benefits.


Key points of the standard

What should be standardized: How model equations are formulated. How model is coded. How model is implemented into simulators. A benchmarking procedure and the benchmarks

required to validate the model. How to extract parameters and verify libraries.


A GNU Compact Model DevKit

The open standard should lead to a free compact model development kit.

The DevKit will be an integrated suite of tools that will interface with the parametric measurement instrumentation on one end and with circuit simulators on the other.

The DevKit will integrate into IC-CAD flows to evaluate models on real circuits.


A GNU Compact Model DevKit

The bottleneck today is the implementation of compact models into circuit simulators.

CM-DevKit must allow for easily integration of the models into each simulator’s compiled model interface (compliant approach).

CM-DevKit must be able to process measured data to generate parameters sets.


The CM DevKit – key tools

1. A compact model capture tool (to generate a Verilog-A or VHDL-AMS description of the model).

2. A compact model analyzer/synthesizer (to generate an intermediate form).

3. A set of intermediate form languages compiler and interpreters to assist in model development, playback and debug.

4. Circuit simulators to evaluate the model (both free and commercial).

5. A parameter extraction tool.


The CM DevKit – Model Capture

Existing tools: gEDA is an extensible

schematic capture tool able to generate spice netlist from schematics.

Paragon (?)

Open Issue: There is no gEDA

verilog-A or VHDL-AMS extension.

There is no capture environment specifically targeted to CM development.


The CM DevKit – Model synthesizer

Existing tools: ADMS (Laurent -

Freescale). This tool generate

codes that can be compiled into simulators using their CM extensions.

Generated code runs almost at the same speed of human written code.

Open Issues: ADMS is under

development. ADMS translation script

writing is poorly documented.


The CM DevKit – Intermediate languages

Languages Tcl/Tk Python C / C++

Open Issues: None!

Tcl/Tk and Python are already used in CAD flows and most of the simulators provide a C/C++ API for CM integration.


The CM DevKit - Simulators

Existing tools: fREEDA GNUcap Ngspice QUCS

Open Issues: Input language

compatibility. Common set of analyses. Common set of modeling

API. Common data output

format.


The CM DevKit – Simulators

The ADMS approach of translating the model description into each simulator’s API is winning as does not require any intervention on the simulator itself.

Faster development time, no more implementation bottleneck.


The CM DevKit - Extraction

Existing tools: None!

Octave (free Matlab-like software) should be used to process IC-CAP .mdm data.

Open Issues: Need to write an

extraction tool based on a standard “measurement language” that can interface to IC-CAP data server.

Writing a parser for .mdm files.


Benefits of the GNU perspective

No discrimination between models and availability of models for new devices (MEMS/NEMS, etc.)

Model developers will be receive feedback on the models shortly after release as designers can test them on their simulators without the need to wait for CAD vendors implementations.

Model acceptance speed-up, as the end-users entered in the development loop have had more time to evaluate the model (on real circuits) and, by contributing to it, were able to direct the development effort toward what they really needed.


GNU perspective - Summary

The EDA community will benefit by using free compact models conforming to an open standard.

A CM DevKit to integrate CM development into IC-CAD flow can be built using only free/open source software.

The core tools of this DevKit are already in place (ADMS, simulators).


CM Standardization – A GNU perspective

Thank you !


Modeling overall goal

ITRS 2007


DevKit – EKV example 1

Simulator independence

Simulator Version* EKV2.6 LEVEL EKV3.0 LEVEL Comments

ADS 2003C Verilog-A Verilog-A example [wg]

Altium 6.5 8 Released Aug.30 2006

AMI-Spice 3.7a 23 released

APLAC 7.30h EKVMOS to be announced

AVOSpice 1.82.0805 Verilog-A Verilog-A

ELDO 4.6 44 (UPDATE=2.6) 61 Verilog-A in beta

Golden Gate 4 ekv ekv3

HSIM 2 55

IntuSoft ICAP/4 shipping

LTspice/SwitcherCAD III 1.09p 12 free download

MacSpice 3f5p10 44 free download

MI-SUGAR 0.4.4 44 Mac OSX

Micro-Cap 8.0.0 44 available now

MINIMOS-NT 2 Devices.{N;P}MosEkv with selfheating

NanoSpice 1.1 55


DevKit – EKV Example 2 Simulator Version* EKV2.6 LEVEL EKV3.0 LEVEL Comments

Nexxim 1 55 Verilog-A

NG-Spice rev.17 Verilog-A Verilog-A free download

PSPICE [*] 9 5 thru XML-ADMS

Qucs 0.0.14 Verilog-A Verilog-A

SABER 4.3.2

SIMetrix 4.1 44 released Feb 2002

SmartSpice 1.5.5.R 55

SMASH 4.1 5 ekv3 and Verilog-A released

Spectre 4.43 ekv Verilog-A tested at LEG

SpectreRF 6 ekv Verilog-A

Spice-Opus 2.04 44 Verilog-A available

SPICE3 3f5 Verilog-A Verilog-A tested [wg]

Star-Hspice 98.4 55 Verilog-A also CML libs

Synopsys 98.4 55 Verilog-A also CML libs

T-Spice 11 44 or 55 Verilog-A also CML libs

TopSPICE 6.9 44 or 55

TRANZ-TRAN 3.5

WinSpice 1.03.02 44 free download

1st mos-ak international meeting - san francisco dec. 13th, 2008 compact model standardization – a...

Documents

development of model

compact model standardization

model release

model equations

free modelthe compact

lack of models

class models bsim

circuit simulators