Printed Circuit Design & Fab - November 2008 - (Page 32)

MEASUREMENT AND SIMULATION parasitics that will appear in the prototyping stages than bread boarding and other ‘traditional’ design approaches. To improve simulation, we need to improve any remaining idealized or simple models. When evaluating the simulation environment, it is important to note that design factors such as noise, cross talk or even the complex nature of a signal (perhaps a heartbeat or mechanical signal) are not traditionally included as a stimulus in simulation. This is because the source that usually validates a schematic is based on a simple curve, such as a sine wave or square wave. This can be considered as the most prevalent source of idealization on the individual engineer’s desktop. If this source model can be improved to better represent a real signal, then we can increase the effectiveness of simulation. The idea is therefore to try to plug a real source into a schematic and simulate it based on a real signal. Real measurements have typically not played a standard role at such an early stage of design. The first instance of real signals being introduced to the design flow has typically been during prototype validation. However, through an earlier introduction, we can facilitate a far improved simulation model of a stimulus. tional stimuli can be introduced earlier in design for a more effective approach. Modern measurement hardware is able to acquire real signals and to save it to an ASCII text format. This can be done both by manually transferring it (via disk or thumb drive) to a PC, or more easily, by using the PC directly through a General Purpose Interface Bus (GPIB) to acquire and to save measurements. Simulation software can then load the text-based measurements as a stimulus for simulation. 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ADVERTISER Added Value Technology Alternate Finishing PAGE # 35 46 ADVERTISER Bare Board Group Cookson Electronics PAGE45 # Added Value Technology 35 13 Alternate Finishing 46 DownStream Group 11 Bare Board Technologies 45 EDA Tech Forum DEMS Insert opposite47 39 DownStream Technologies 11 eFabPCB 45 EDA Tech Forum 47 EMA Design Automation 7 eFabPCB 45 EzPCB Design Automation 457 EMA Fine Circuits 46 Enthone 13 Enthone Chinese46 S3 FreeDfM EzPCB 45 Front Panel Express 44 Fine Circuits 46 HKPCA 2008 42 FreeDfM 46 HMS Höllmüller Maschinenbau 21 Front Panel Express 44 HKPCA 2008 42 Imagineering 3 HMS Höllmüller Maschinenbau 21 Imagineering 44 Imagineering 3 JetPCB 44 Imagineering 44 MacDermid 5 JetPCB 44 MacDermid Mentor Graphics Cover 45 MentorAccurate Grinding Graphics Intro Midwest 46 Mentor Graphics – National Instruments/ Cover 38 Webinar Insert opposite 2 ElectronicsAccurate Grinding Workbench Group Midwest 46 National Oak-MitsuiInstruments/ 17 Electronics Workbench Group Cover 2 Ohmega Technologies 27 Oak-Mitsui 17 One-Stop Assembly 44 Ohmega Technologies 27 Online Electronics 44 Ohmega Technologies Chinese S19 One-Stop Assembly 44 PCB FAB Express 46 Online Electronics 44 PCB Orlando 2008 37 PCB FAB Express 46 PCB-Pool 23 PCB Orlando 2008 37 Plasma Etch 29 PCB-Pool 23 Plasma Technologies 29 Precision Etch 46 Precision Technologies 46 Rohm and Haas 19 Rogers Chinese S7-S8 Samtec and Haas 15 Rohm 19 SEP Co. 45 Samtec 15 SEP Co. Sierra Proto Express Cover 45 3 Sierra Proto Cover 3 Sun Chemical Express Circuits 25 Subscriptions Chinese S29 Sunstone Circuits 1 Sun Chemical Circuits 25 Superior Processing 451 Sunstone Circuits Superior Processing 45 Taiyo America 33 Taiyo America 33 Technical Machine Products 46 Technical Machine Products 46 Uyemura 99 Uyemura Virtual PCB 31 Virtual PCB 31 The advertising index is published as an additional service. The The advertising index is published as an additional service. publisher does not assume any liability for errors or omissions. The publisher does not assume any liability for errors or omissions. A Shift in Design Practices Making the transition of design analysis to an earlier stage of the design flow requires a shift in the thinking of the electronics design community. With as many as 28% of small companies requiring as many as three respins of designs, as noted in a report by the Aberdeen Group in 2007, it is apparent that there is still room to improve and to address issues earlier in the design flow. In the past few years, innovation has created Design for Manufacturing (DfM) and Design for Assembly (DfA). The intent is to analyze a design earlier in order to understand the potential for fabrication and manufacturing issues. Integration of the PCB design flow with manufacturing tools has created an EDAindustry-aided infrastructure to shift the focus of appropriate fabrication information, data and techniques earlier. We are now able to aid manufacturing by shifting analysis even earlier through a more effective use of simulation. Combining real measurements with simulation provides an effective platform to reduce errors even earlier. The Virtual Prototype The integration of simulation and real stimuli in a systematic design approach is termed Virtual Prototyping — bridging the gap between emulated behavior and reality to build a more effective computer-based model. This is seen in multiple industries including mechanical and construction engineering. An electronic system, for example, must often interface to a mechanical force. A mechanical stimulus can introduce a repetitive noisy element to the input of a designed PCB. If not accounted for at this time, then it will not be identified and resolved until prototype validation —when it is implemented into a system. Introduction of this signal as a simulation stimulus will help visualize the effect of that noise before the prototype stage. Filtering and signal conditioning for this element of the design can be built before the first iteration. Again, biomedical signals, noisy inputs, periodic functions and nontradi- Building the Virtual Prototype into the Design Approach The idea is that for a successful approach to design, the virtual prototype should be employed as a third and final validation stage prior to prototyping. There are three stages of simulation-aided validation: component evaluation, iterative simulation and analyses and virtual prototyping. The first stage of simulation use is based on the evaluation of components — judging the performance of transistors, operational amplifiers and other devices in small modular circuits to assess their NOVEMBER 2008 32 PRINTED CIRCUIT DESIGN & FAB http://www.pcdandf.com http://www.alternatefinishing.com http://www.bareboard.com http://www.circuitsassembly.com/dems http://www.downstreamtech.com http://www.edatechforum.com http://www.efabpcb.com http://www.ema-eda.com/training/seminars.aspx?campaignID=148 http://www.envisionrules.com http://www.ezpcb.com http://www.finecircuits.com http://www.freedfm.com http://www.frontpanelexpress.com http://www.hkpca-ipc-show.org/visitor http://www.hms-germany.de http://www.pcbnet.com http://www.jetpcb.com http://www.macdermid.com/electronics/ http://www.mentor.com/pcb http://www.pcbshows.com/webinars/events/mentor/ecad.shtml http://www.midwestaccurate.com http://www.ni.com/multisim http://www.oakmitsui.com http://www.ohmega.com http://www.onestopassembly.com http://www.pcborder.com http://www.pcbfabexpress.com http://www.pcbshows.com/orlando http://www.pcb-pool.com/ppus/info.html?PHPSESSID=7df48fa7c977776045ff8d4b24a70fc7 http://www.plasmaetch.com http://www.eprotos.com http://www.rogerscorporation.com/acm http://www.rohmhaas.com http://www.samtec.com/tls http://www.sep.co.kr http://www.protoexpress.com http://www.pcdandf.com http://www.sunchemical.com http://www.sunstone.com http://www.superior-processing.com http://www.taiyo-america.com http://www.techmach.com http://www.uyemura.com http://www.virtual-pcb.com

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - November 2008

Printed Circuit Design & Fab - November 2008 Contents Our Line Market Watch Around the World Happenings ROI Positive Plating Ten Tips to Improve Manufacturability 3D Chip-Package-Board Modeling Improving Circuit Simulation With The Addition Of Real Measurements Ad Index PCB West: Interview with NBS Design Inc. The Influence of Final Finish on Lead-Free Assembly Reliability The Lead-free Soldering Challenges for Peelable Resists Off the Shelf Marketplace BGA Bulletin

Printed Circuit Design & Fab - November 2008

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