疑难解答/FAQ

Q1	I am a university student. Current I am using SILVACO's analog design flow (AMS suite and ICCAD suite, including schematic capture, simulation, layout and its verification) from my lab. The tools are fantastic but I am new to SILVACO EDA tools and would like to get familiar with them fast. Is there any examples from which I can gain an overview of these tools?

Q2	I used to work with multi-window schematic capture tools. How can I switch easily among several opened schematic sheets in Gateway which is single-window based?

Q3	How do I make my long simulation more memory efficient?

Q4	I have set the RAWPTS option in my input deck when I ran transient; however, if my simulation is terminated unexpected, how can recover previous simulation result and resume the remaining part?

Q1	I am a university student. Current I am using SILVACO's analog design flow (AMS suite and ICCAD suite, including schematic capture, simulation, layout and its verification) from my lab. The tools are fantastic but I am new to SILVACO EDA tools and would like to get familiar with them fast. Is there any examples from which I can gain an overview of these tools?
A1	There are quite a lot of examples packaged together with the software, most of which are in /examples/. Besides, in manuals of certain products, some examples are explained in details such as Smartspice User's Guide Volume 2, etc. If we are interested in getting an overall idea on how SILVACO analog suite works, we can try to use SILVACO Demo PDKs. SILVACO has developed 5 sets of demo process design kits (PDKs): SILVACO Analogue Demo PDK, Logic Demo PDK, Mixed-Signal Demo PDK, Radio Frequency Demo PDK and MOSIS SCMOS PDK. They can be downloaded by any registered SILVACO Resource Centre users from: https://dynamic.silvaco.com/dynamicweb/silcn/ freely and installed easily using SILVACO Management Console (sman) -> Products -> Add and Manage Updates. Inside those PDK packages, there are detailed user manuals, all necessary files and of course, the ready-made examples from which we can start right away. Here is another small example using SILVACO analogue flow for your reference (SILVACO Analogue Demo PDK)
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Q2	I used to work with multi-window schematic capture tools. How can I switch easily among several opened schematic sheets in Gateway which is single-window based?
A2	We can select sheets from Gateway Windows. Or we minimize/Restore down the current sheet and then select another. The most convenient way is to press Ctrl + Tab to switch among sheets. The Gateway’s “Preview” dock window is a very useful feature; it will provide an overview of current schematic sheet and give the user an idea on which schematic he or she is navigating to.
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Q3	How do I make my long simulation more memory efficient?
A3	When we run a long simulation time analysis the evaluated time points are normally all held in memory until the end time is reached. All the data is then written out to the output rawfile. This means a large amount of system memory can be used up and also has to be tracked. If in the input deck the line ".OPTIONS RAWPTS=300 POST" is included then as soon as the maximum number of points is reached given by "RAWPTS=300" then all the vector data is saved to the raw data output file and the memory is free to be re-used. In this way the output rawfile is incrementally increased in size every time this limit is reached. The memory required by the simulation run is therefore reduced, and with less memory to manage, the simulation is run faster. This is particularly useful on the PC platform where some of the memory is required for the operating system and RAM size is less than 1Gig.
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Q4	I have set the RAWPTS option in my input deck when I ran transient; however, if my simulation is terminated unexpected, how can recover previous simulation result and resume the remaining part?
A4	SMARTSPICE is capable of recovering from an unexpected program termination during a transient analysis simulation. This functionality is performed through so called checkpoint files and is disabled by default. It can be activated through the environment variable or command line option +checkpoint. For example, for an input deck that contains either of following statement/option: .TRAN 0.1NS 1000u ckptperiod=20 or .option CKPTCLOCK=20 Where "20" refers to the time interval (in unit of second) for Smartspice to save transient data into an ".sav" file. If it is run with "smartspice +checkpoint" command, the .sav file will be saved in every 20 seconds. If the simulation was terminated, the transient analysis can be restored by "smartspice +checkpoint +recover" command, loading the ".sav" file that we just saved previously. If we are simulating a large circuit for a very long transient time, beside RAWPTS and above checkpoint-restore feature, we can add ".OPTIONS SAFEMODE" to warn users if the simulation run consumers too much resources. Another way is instead of the ".SAVE ALL" we can record certain vectors of interest from part of whole circuit.
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