Borbely Fet Follower SPICE modeling

[fscarpa58]

Thank you again for the info, Peter

F.

 

[pjacobi]

Hi Christer, All,

Although I haven't really investigated that many manufacturers
models, my impression is that also BJT model are often mediocre
at best when compared to the datasheets.[...]

Just popping this thread to the front page to note, that LTSpice just got the VBIC model implemented (as I have the impression, not all LTSpicers here are on the mailing list).

Mike's example to see the differences is this deck:
* Verilog-A vbic_3T_it_cf test circuit
vbe bx 0 0
vcb cx bx 0
vib bx b 0
vic cx c 0
q1 c b 0 vbic
.model vbic npn(level=9 RCX=10 RCI=10 RBX=1 RBI=10 RE=1 RBP=10 RS=10
IBEN=1.0e-13 RTH=100)
.dc vbe 0.5 1.0 0.001
.probe i(vib) i(vic)
.end

Do a gummel plot (log(i(vib)) and log(i(vic))) or simply i(vic)/i(vib)

For an intro to VBIC, see e.g. http://people.web.psi.ch/palfinger/dipl/dipl/node3.html

Regards,
Peter Jacobi

 

[lineup]

This is for the SPICE modeling related discussions,
which started in the "Borbely Fet Follower" thread.

Let's avoid annoying the thread starter and others, who want to see practical issues, real circuits, discussed in that thread.

Regards,
Peter Jacobi

Hi Federico, All,

JFETs, the neglected stepchild of SPICE modeling?
----------

Compare these Philips models with the datasheets:
----------
This almost makes sense, doesn't it? Add impact ionization current to prevent designers setting Vds too high, and the models would be good enough for most simulations.

Compare with power BJTs.
Almost no models implement quasi-saturation.
Didn't stop us from using them.

Hexfets?
If used in class B amplifiers, devices spend signifant part of the cycle in weak inversion,
but you'll find models which doesn't model diffusion current at all!

Regards,
Peter Jacobi

Hi, Peter Jacobi.
I hope you read this ... 🙂

I was searching for some better JFET BF245 A/B/C models.
Because I do not trust them I have ... I have some doubts 😀
Now, I ended up in this execellent thread 😎

Using Modified Tube Penthode model Formula, to better predict JFET
Great!
Give me some of those, please.

Spicy simulated regards, Lineup