Transcript Document

Compact model
standardization – a GNU
perspective
Paolo Nenzi - CNR-INFM
Wladek Grabinski - GMC
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
Perspectives

Actual:
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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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
Consequences

Actual perspective



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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.)
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
An Open Standard

The GNU compact model standard should be
open (as defined by OSI):



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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)
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
Key points of the standard

What should be standardized:
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
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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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
A GNU Compact Model DevKit
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
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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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
The CM DevKit – key tools
1.
2.
3.
4.
5.
A compact model capture tool (to generate a
Verilog-A or VHDL-AMS description of the model).
A compact model analyzer/synthesizer (to
generate an intermediate form).
A set of intermediate form languages compiler and
interpreters to assist in model development,
playback and debug.
Circuit simulators to evaluate the model (both free
and commercial).
A parameter extraction tool.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
The CM DevKit – Intermediate
languages
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Languages

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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.

1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
The CM DevKit - Simulators
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Existing tools:



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fREEDA
GNUcap
Ngspice
QUCS
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Open Issues:




Input language
compatibility.
Common set of analyses.
Common set of modeling
API.
Common data output
format.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
The CM DevKit - Extraction


Existing tools:
None!
Octave (free Matlab-like
software) should be
used to process ICCAP .mdm data.

Open Issues:


Need
to
write
an
extraction tool based on
a
standard
“measurement language”
that can interface to ICCAP data server.
Writing a parser for .mdm
files.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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.
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
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).
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
CM Standardization – A GNU
perspective
Thank you !
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
Modeling overall goal
ITRS 2007
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
DevKit – EKV example 1

Simulator independence
Simulator
ADS
Version*
EKV2.6 LEVEL
2003C
Altium
EKV3.0 LEVEL
Verilog-A
6.5
Verilog-A
8
3.7a
23
APLAC
7.30h
EKVMOS
AVOSpice
1.82.0805
Verilog-A
Verilog-A
44 (UPDATE=2.6)
61 Verilog-A
ekv
ekv3
4.6
Golden Gate
4
HSIM
2
example [wg]
Released Aug.30 2006
AMI-Spice
ELDO
Comments
released
to be announced
in beta
55
IntuSoft
ICAP/4
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
NanoSpice
shipping
2
1.1
Devices.{N;P}MosEkv
with selfheating
55
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
DevKit – EKV Example 2
Simulator
Version*
Nexxim
NG-Spice
1
rev.17
PSPICE [*]
0.0.14
SABER
4.3.2
SIMetrix
Verilog-A
Verilog-A
4.1
Spectre
4.43
6
SPICE3
Verilog-A
released Feb 2002
55
SMASH
Spice-Opus
free download
thru XML-ADMS
44
1.5.5.R
Comments
Verilog-A
Verilog-A
5
4.1
SpectreRF
EKV3.0 LEVEL
55
9
Qucs
SmartSpice
EKV2.6 LEVEL
5
ekv3 and Verilog-A
released
ekv
Verilog-A
tested at LEG
ekv
Verilog-A
2.04
3f5
44
Verilog-A
Verilog-A
available
Verilog-A
tested [wg]
Star-Hspice
98.4
55
Verilog-A
also CML libs
Synopsys
98.4
55
Verilog-A
also CML libs
Verilog-A
also CML libs
T-Spice
11
44 or 55
TopSPICE
6.9
44 or 55
TRANZ-TRAN
3.5
WinSpice
1.03.02
44
1st MOS-AK International Meeting - San
Francisco Dec. 13th, 2008
free download