Hello again! I'm making the layout of a diode from...
# analog-design
j
Hello again! I'm making the layout of a diode from scratch. I basically used the same structure of the PDK's diodes but making the diode bigger. The thing is that, after performing parasitic extractions (specifically when running R extraction), I get this error. Does someone know why is this happening?
t
I am still tracking down various
extresist
problems. Make sure you are using the most recent version of magic, but if the problem persists (and most likely it will), feel free to post the layout so I can look into it.
j
I've already tried updating magic, checking if the layout is correct but everything seems fine and still, the error persists. Here is the layout if you want to have a look. Thanks, Tim.
t
Thanks for the example layout. I had thought that the "missing terminal" (which I've also seen on nFETs) was due to the use of an implicit substrate (no "pwell" layer drawn), but this example shows that's not the case.
The example also shows up another problem that I didn't know about---the diode contact isn't in the list of resistances in the extraction setup for magic, so it does not have the approximately 185 ohms / 4 cuts = 46 ohms resistance that it should have.
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j
Could the "Missing terminal connection" error be caused by the absence of the diode contact in the list of resistances?
t
Always possible, but I've seen similar errors that had nothing to do with diodes, so I'm expecting an annoyingly difficult time debugging it.
j
Got it. Thanks for the answer, Tim. 😄
t
I just corrected this in magic, but as far as I can tell, the only issue is that extresist prints incorrect messages about missing terminals. There didn't seem to be any change in the actual output.
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