Andrew Beckett
Guest
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Posted:
Fri Nov 11, 2005 1:10 pm Post subject:
Re: Current of Spectre simulation |
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On Fri, 11 Nov 2005 08:07:07 +0100, Svenn Are Bjerkem <svenn.are@bjerkem.de>
wrote:
| Quote: | In article <437368fc$0$1151$5402220f@news.sunrise.ch>,
xintian.shi@unine.ch says...
Two transistors are connected in serial, but the
currents of the 2 transistors are not equal.
Do you have bulk contacts? Any current there?
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Also, you have to be aware that the gmin conductances added for convergence
(normally 1e-12 mho) also draw some current...
Other explanations can be that you have the devices implemented as inline
subckts, where there is more than one component connected to the pin. WIth
inline subckts, the current reported is the current through the inline device,
not the whole subckt.
Another problem can be that there have been bugs in the past where the current
reporting was incorrect (it was solved correctly, but reported wrongly) with
some device types. However, I believe all these issues have been resolved
now (the most recent I'm aware of was the current through the bulk pin of a
bsim4, if I remember rightly). Check to see if setting "useprobes=yes" (via the
Save All form in ADE) fixes it (this tells spectre to always measure currents by
putting an iprobe in series rather than using the built-in current output of the
device).
Regards,
Andrew.
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