Mystery SI Guy: I have been using Allegro PCB SI (formerly SpecctraQuest) for SI and STA for many years. Yes, it has its share of bugs and issues but the tool produces good results when you understand what it is doing. This is the same with any SI tool, garbage in = garbage out. You have to know how to drive the tool. It is a very powerful but also complex tool with a lot of features. You have to learn how to use them and understand what the tool is doing. The basic issue with any IBIS simulator is having a good IBIS model. Experience is learning to recognize when you have a bad model. Experience is recognizing when the tool result is probably incorrect and then figuring out either what you did wrong or is the tool really not giving you proper results. Cadence is very quick to respond to real bugs with the tool and their senior FAEs are really understand SI. We get good results with interfaces such as DDR, DDR2, GDDR3, and CML interfaces at 3.125Gbps with good correlation with scope, VNA, TDR, and BERT measurements, etc. You can also simulate with pre-emphasis if you take some time to create a macro-model. I haven't found a tool that lets you perform an SI and STA analysis for a complex board as quickly as Allegro PCB SI. Whoever you were talking to is probably a neophyte at both SI and with the tool. I have experience with other tools and HSPICE and they all have their share of issues. Even HSPICE has bugs and lack of agreement with measurements under certain conditions such as longer lossy lines. Try doing a full board analysis with HSPICE in 2 to 3 weeks. Cadence will give you a trial license and support for some period. Just make sure you have both the time and a real problem to use it on to verify for yourself if the results are valid. Your best bet is a functioning board that has gone through a verification cycle so you have measurements to compare to the simulations. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of mystery guy Sent: Tuesday, November 22, 2005 5:06 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] HELP!! SpecctraQuest is GOOD/BAD Tool for Board Level Simulation < 400 MT/s??? Gurus, I recently heard a fellow say that SpecctraQuest is not an acceptable tool for SI simulation (timing, signal quality) due to imperfections and/or bugs in the program. Basically, the assertion was that the tool would not generate correct results. I would like some opinions from industry experts as to the viability of the tool. The application I am interested in is board level simulation of digital busses using IBIS models. I plan to use the tool primarily to investigate solution space via flight time analysis. Signal quality issues (ringback, non-monotonicities) would limit my solution space as well. Can this tool be used for such a purpose, or does the SI community generally expect faulty results from this tool? BTW, switching frequencies for most busses I would be working on is less than 400 MT/s. Are other SI experts in the industry using SpecctraQuest to simulate such busses? Are other folks in the industry yielding accurate results using this tool, or should I discount the use of this tool as a bad choice based on collective industry experience? Please respond... the more responses I get, the more confidence I have in tool selection. I will post the results of poll as favorable # vs. unfavorable # of responses should the forum be interested. Thanks, -A Concerned SI Guy --------------------------------- Yahoo! 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