Hello all,I tried to model on-chip spiral inductors according to the SpectreRF User Guide. To this end, I wrote the process file according to my process data (AMS 035 HV), inserted the inductor symbol from the passiveLib and specified the geometrical data in the CDS window. For some reason, the parameter extraction that is performed prior to simulation only works for a rectangular shaped inductor (and not for octagonal and circular shapes). The error message in the log file looks as follows:Internal err: dist_bet_pt_and_fil: why is t = 1?Also, the inductance values that are extracted for the rectangular case are not conform with those calculated by other tools/formulae (Wheeler, performing integration in MATLAB, Mohan equation from Tom Lee's book) but differ by a factor of 15.Thanks in advance for any advice.Best regards,Jens
It sounds as if you may be using the obsolete (and end-of-lifed) old passive component modelling tool which was rather basic.In MMSIM61 (best to use a recent ISR, since it is being enhanced all the time) there is a tool Virtuoso Passive Component Modeller (it needs two MMSIM tokens), which is a inductor/transformer/transmission line synthesis tool and EM solver for analysing inductors etc, and this is far, far superior to the previous very basic solution.This will generate pcells, symbols, s-parameter files and lumped models for your technology, and will synthesize an inductor given a target L, Q, SRF, and so on.Regards,Andrew.
Thanks a lot Andrew,I changed to the VPCM tool and it works fine. The only problem I had was to generate the right s-parameter file for circular shaped coils. In the header of the BSimProplus RF data file you have to manually add geometrical information, including the shape. Unfortunately, I could not find the right coding (number) for circular shape. Could anybody help me on that issue?
Apologies for the delay - been a bit busy recently...Not quite sure I understand. Are you synthesizing a circular inductor? What exactly are you having to edit, and at which point?Regards,Andrew.
Thanks a lot for your efforts and sorry for giving a rather fuzzy description of my problem!So here's a second try:In the "preparing input data files" for the model trainer section of the VPCM user guide it is said that one has to add the geometry information of the coil to the BsimProPlus RF file containing the s-parameter data obtained from EM-simulations. There, apart from the width, the spacing, etc. one also has to specify the shape of the inductor. Unfortunately, the VPCM user guide does not say how you specify a circular spiral inductor 8 stands for octagon and I found by trial and error that 4 stands for rectangular, but I have no idea which number denotes a circular one.I hope that was more precise then last time,Jens