Re: [buildcheapeeg] Re: DRL SPICE model

From: Joerg Hansmann (info_at_jhansmann.de)
Date: 2002-01-31 01:05:52


Hi Andreas,

----- Original Message -----
From: sleeper75se <sleeper75se_at_yahoo.se>
To: <buildcheapeeg_at_yahoogroups.com>
Sent: Wednesday, January 30, 2002 8:08 PM
Subject: [buildcheapeeg] Re: DRL SPICE model

...
> > like the TI INA114 and TLC272. You must copy the *.sub into the
> > "\SwCADIII\lib\sub" directory and all *.asy
> > to "\SwCADIII\lib\sym\Opamps"
>
> Hmm, I can't seem to get it to work...the program says it can't find
> the models.

Strange...

Did you restart SWCAD after copying the files to the above directories ?
Or was SWCAD active the whole time ?

If you make a new schematic can you then pick the new types from
the opamp part selector ?

> Do I need to make a .lib file with the model definitions
> as well?

I have not changed anything in the LTC.LIB file and it does not
have any new entries like TLC272 or INA114. So neither I nor
SWCAD (without my knowledge) have changed the LTC.LIB

> It choked on your protection circuit too... and it has
> convergence problems sometimes.

I have only tried AC analysis until now. Where did you get
convergence problems ? Have you changed anything in the menu
"tools->control panel" e.g. convergence hacks and options ?

> Are we using different versions? I am
> running version 1.10v (Got it from the about-box)

The same as my version.

> Anyway, I removed the protection circuit, replaced the IC's with
> Linear models and played around a bit. Looks stable! :-) Things look
> even better using the human-body model (100pF/1500ohms). Don't know
> if it applies here though.

Probably more than the 300pF, because this was a kind of worst case
measured from patient to earth. Because the reference potential of
the EEG is isolated from earth the effective capacitance will be
much smaller (capacitance from human body to EEG pcb and cables, perhaps
50 pF)

Regards,

Joerg



This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:37 BST