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  1. #1
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    Calibre xRC Extraction Device Overlap

    Hello,

    Does anyone know what might be causing device overlap in a generated calibre extracted view? It seems as if the devices are automatically placed too close together and I get errors that the devices have shorted as a result of this. When I reduce the magnify value, it doesn't seem to help this either.

    - - - Updated - - -

    Just an update in case anyone else has this issue...I was able to figure this out. It wasn't enough to just change the magnify option, you also need to enable output R locations and output C locations in the PEX Options menu.

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    Re: Calibre xRC Extraction Device Overlap

    If you use 'Arrayed' arrangement, not as 'Layout locations' than it will also solve this as I remember. And the calibre view size will be smaller too. I have no idea why does it happen.



    •   Alt10th October 2017, 21:59

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  3. #3
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    Re: Calibre xRC Extraction Device Overlap

    I noticed that the arrayed arrangement works too. Apparently its something to do with the auLvs devices. Just out of curiosity, did you have to do any CDL processing on your netlists? I'm having trouble properly referencing my triple well devices, PEX removes the wells and extracts them as parasitic diodes. However, the config file doesn't reference the 4 terminal model, it still references the 6 terminal model.



    •   Alt11th October 2017, 00:01

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    Re: Calibre xRC Extraction Device Overlap

    I have never used 6 terminal devices actually, and fortunately I haven't done CDL processing either. I would think those are RF devices and use double guard rings automatically connected to the VSS!,VDD!. Than the parasitic diode represents the reverse biased PN junction at the guard rings. Are you using config file because you need hierarchy editor? I think maybe enough for you to set the Environment at the Data View panel on your Test. To simulate calibre view the Hierarchy editor is not necessary, it is just useful if you have a lot of subblocks.



    •   Alt11th October 2017, 17:54

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    Re: Calibre xRC Extraction Device Overlap

    How would you go about setting it up in the dataview window? If you've got a test bench setup, wouldn't you need to include both spectre and caliber models?



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    Re: Calibre xRC Extraction Device Overlap

    I think yes, you need both of them, sorry, but if you type calibre view name between 'spectre' and 'schematic' at the Environment you can skip the use of config view. I just wanted to give a tip to make simulation easier, you can check the netlist by click on 'Recreate'. And maybe it is not a problem if your calibre view contains the 4T devices and the parasitic diodes, but I don't know exactly.



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    Re: Calibre xRC Extraction Device Overlap

    Tried this, doesn't work because I'm not just simulating the block, it's a part of a testbench, and the testbench does not have a calibre view. I'll update when I figure it out.



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    Re: Calibre xRC Extraction Device Overlap

    Use the testnench's view name after the calibre view name, it has to work.

    example at the environment 'Switch view list': spectre calibre_RCC schematic veriloga
    So if your testbench doesn't have a calibre view the cadence will search for a schematic view of it, than for a veriloga.



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    Re: Calibre xRC Extraction Device Overlap

    Oh right, I completely forgot that you can set the switch view in ADEXL. Just tried that though, same issue. I'm getting an error that a noxref instance is referencing an undefined model NFETIM4. This is because of the way the models were extracted. My netlisted model is NFETIM.



    •   Alt13th October 2017, 12:43

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    Re: Calibre xRC Extraction Device Overlap

    Add the .scs file to the test at the model libraries, which contains NFETIM4 model. You have to define for the simulator where it can find the correct model.



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    Re: Calibre xRC Extraction Device Overlap

    Sorry, I did that too. I have an nfetim4.scs model. But when I run my CDL processing script it changes the name in my netlist to NFETIM4. I am wondering if this change is why it is not being recognized? I do not have a NFETIM4.scs model. Can I copy the nfetim4.scs model file over somewhere else and change the name, or would that not work right?



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    Re: Calibre xRC Extraction Device Overlap

    Sorry, I don't know what your script does, as I mentioned I have never needed CDL processing to simulate. And the model's name isn't coming from the scs file's name. If you open the scs file with gedit, or notepad, anything than there should be a line for your device, like: model nfetim4 bsim4 ....... I don't suggest to rewrite that. And if you open the calibre view, press q on a 4T device to see the properties, find the row 'Model name'. That is the exact model name which you have to look for in the corresponding scs file.



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