This item from Tarek Mealy showed
up on my LinkedIn feed. He created a nifty software app called "SymMos" that allows you to use a
drag-and-drop interface to create a schematic using MOSFETs, resistors,
inductors, capacitors, bias voltages, and signal sources. Then, click on the
appropriate button to get the transfer function equation for input impedance,
gain, transconductance, or noise figure. SymMos is a work in progress and is
available as a free download.
After unzipping the file, you need to change the SymMos.txt file extension to
.exe. Launch the executable and then you'll need to wait many seconds while the
program loads (a black screen is displayed while waiting). BTW, Norton flagged
the file as dangerous since it is new and hasn't seen it before, but I allowed
it to run anyway with no problems. I recreated the example shown in the YouTube
video and it works as advertised.
From Tarek Mealy's
LinkedIn post regarding SymMos:
"After a bad interview experience from 5 months ago where I forgot the
expression of the input impedance seen from the gate for NMOS with inductance
degeneration and I had to derive it during the interview, I thought why we don’t
have a software that do the derivation for us!
I used to memorize the expressions for commonly used analog circuits, but I
sometimes forget some of the expressions and therefore I have to bring a pen and
a paper to derive it from scratch based on small-signal model.
After the interview, I was self-motivated to write a python code with GUI
that allows to draw any circuit with MOS transistors and find the symbolic
expressions for impedances, gain, transconductance and noise figure.
I named this software SymMos and I made this introductory video to show how
Posted June 27, 2022
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