Software Tools for CM Standardization Laurent Lemaitre

Contents Verilog-AMS: Brief Introduction ADMS: open-source tool that facilitates compact model introduction and maintenance of compact models ZSPICE: simple spice simulator that facilitates bench- marking and distribution of new compact models Conclusion

What is Verilog-AMS? Verilog-AMS is a hardware description language used as a behavioral language for analog circuit simulators Verilog-AMS gives analog designers a means to encapsulate behavioral description of analog systems into modules Verilog-AMS can be re-used for compact device modeling: L. Lemaitre, ADMS – Automatic Device Model Synthesizer, cicc2002 M. Mierzwinski, Changing the Paradigm for Compact Model Integration in Circuit Simulators Using Verilog-A, nanotech2003 K. Kundert, Automatic Model Compilation, An Idea Whose Time has Come More info at

Verilog-AMS - Code Example `include "std.va" `include "const.va" module mosfet (d,g,s,b); inout d,g,s,b ; // external nodes electrical d,g,s,b ; // external nodes real x, VG, VS, VD, VGprime, VP; real beta, n, iff, ir, Ispec, Id; parameter real VTO = 0.5 from[0.0:inf]; parameter real GAMMA = 0.7 from[0.0:inf]; parameter real PHI = 0.5 from[0.2:inf]; analog begin VGprime = VG - VTO + PHI + GAMMA * sqrt(PHI); beta = KP * (W/L) * (1.0/(1.0 + THETA * VP)); x=(VP-VS)/$vt; iff = (ln(1.0+exp( x /2.0)))*(ln(1.0+exp( x /2.0))); x=(VP-VD)/$vt; ir = (ln(1.0+exp( x /2.0)))*(ln(1.0+exp( x /2.0))); Ispec = 2 * n * beta * $vt * $vt; Id = Ispec * (iff - ir); I(d,s) <+ Id; end // analog endmodule

Benefits Using Verilog-ASM For the model developer –Develop once and run everywhere –Focus on model equation, not on implementation For the software vendors –Simplified implementation of the standard models –Proprietary Verilog-A models are also supported For the silicon fab –Standardized model parameter set For the end-users (designers) –Standardized libraries and design kits

ADMS - Basics ADMS: Project Summary ADMS is a code generator that converts electrical compact device models specified in high-level description language into ready-to-compile c code for the API of spice simulators. 120 downloads in two weeks (start September 03)

ADMS - Overview ADMS Parser XML Internal data Code Generator Other applications Documentation Circuit Test Benches Testing prior implementation C code Mica, Spectre, ADS, Zspice Verilog-AMS Source Code ADMS-XML Simulator-specific Interfaces Other ADMS-XML Interfaces ADMS Data Base

ADMS - getting xml interfaces xml interfaces available for SPECTRE-CADENCE and ADS-AGILENT CADENCE contact CADENCE support & sign NDA request for DPI kit (spectre interface) + xml files AGILENT contact AGILENT support the xml files target the public interface of ADS (no need to download it)

Zspice - Introduction Zspice: Project Summary Zspice is a simple reconfigurable spice simulator. Its device library is automatically generated using ADMS, a software tool available on SourceForge.net. More can be found at:

Zspice - Overview verilog-ams module zspice netlist zspice h file zspice c file cc admsXm l zspiceZkt_dc.xml zspiceModuleH.xml zspiceModuleC.xml zspiceBasic.hzspiceMath.hzspiceInterface.h zsp library zspice results in zspice format results in SVG format svg.pl SVGviewer displays the results inside a web browser

Zspice - Results Available Compact Models Dynamic libraries for win2000 verilog-ams source code descriptionnetlist created by zspiceZkt_dc.xml SPnot providedPSU Surface Potential Model sp_dc.zkt MEXTRANmextran.va, mextran.adms Philips Bipolar Compact Model mextran_dc.zkt BSIM4TBDBerkeley MOS model VBICSELFTvbicselft.va, vbicselft.adms Vertical Bipolar Intercompany Model vbicselt_dc.zkt R3r3.va, r3.admsThree Terminal Resistor r3_dc.zkt EKV team plan to release EKV 3.0 using ZSPICE in October

Zspice - Spice-like Output re-use of existing freeware SVGviewer inside internet explorer

Work in Progress Verilog-AMS subcommittee: started April 2003 mission: extend verilog-AMS to cover compact device modeling adms and zspice proposed as test vehicle for the new language adms and zspice is open-source software (sourceforge.net) adms and zspice developments under the umbrella of this subcommittee Interested Parties: Motorola - Mica Cadence - Spectre Agilent - ADS Nassda - hsim Xpedion - GoldenGate Mentor - Eldo Helsinki University of Technology - Aplac University of Washington – spice3 interface

Conclusion Two open-source tools have been presented Both tools are available on SourceForge.net The development of both projects is very active Visit frequently the SourceForge.net web sites FREE tool downloads Your feedback is welcome