I would like to simulate & lay out a circuit by hand (10 xto

M

Martin C.

Guest
I am not an IC designer but I would like to, for fun, simulate and lay
out a circuit by hand that I can actually understand.

To get a head start, where do you suggest I find a small (ten, maybe
twenty transistors) sized circuit that I can actually understand (being a
business major)?

I found plenty of unsized circuits - which are, in reality, topologies
with missing parts - but - I was hoping to start with a working cmos IC
circuit that works out of the box so that when I simulate it, I could
learn what it is doing - and - so that I could begin to lay it out based
on the actual lengths and widths in the simulated schematic.

Is there a web-available source for very simple sized analog schematics
for learning purposes (i.e., something more than just a digital inverter
block, e.g., an analog op amp, band gap, comparator, vco, pll, etc.)?
 
On Mar 24, 11:35 pm, "Martin C." <martincella...@nospam-gmail.com>
wrote:
I am not an IC designer but I would like to, for fun, simulate and lay
out a circuit by hand that I can actually understand.

To get a head start, where do you suggest I find a small (ten, maybe
twenty transistors) sized circuit that I can actually understand (being a
business major)?

I found plenty of unsized circuits - which are, in reality, topologies
with missing parts - but - I was hoping to start with a working cmos IC
circuit that works out of the box so that when I simulate it, I could
learn what it is doing - and - so that I could begin to lay it out based
on the actual lengths and widths in the simulated schematic.

Is there a web-available source for very simple sized analog schematics
for learning purposes (i.e., something more than just a digital inverter
block, e.g., an analog op amp, band gap, comparator, vco, pll, etc.)?
Click to expand...
If he missed this and doesn't jump in, look up Jim Thompson. Probably
the BEST IC deisgn source and he's tutorial in nature.
 
On Sun, 25 Mar 2012 06:03:48 -0700, Robert Macy wrote:

Is there a web-available source for very simple sized analog schematics
for learning purposes (i.e., something more than just a digital
inverter block, e.g., an analog op amp, band gap, comparator, vco, pll,
etc.)?

If he missed this and doesn't jump in, look up Jim Thompson. Probably
the BEST IC deisgn source and he's tutorial in nature.
Click to expand...
Thanks for the tip.

I found this web site looking up "Jim Thompson IC Design":
http://www.electronicspoint.com/datasheets-schematics-manuals-and-parts-
f87.html

But it seems to be mostly about discrete components.

I also bought the "R. Jacob Baker" book titled:
CMOS Circuit Design, Layout, and Simulation

The problem (so far) is that there isn't a single sized CMOS schematic in
the entire book. Of course, if I were a 'real' EE, the book would be
enough for me to do the sizing myself ... and, I'm sure, that's the right
approach if I were trying to be a circuit designer.

But, for my needs (bearing in mind I'll never be a circuit designer), I
just want a simple analog 'sized' cmos schematic (any design that is
analog and not digital in nature) that I can simulate and probe (and that
a kid could understand once I fully understand it).

I 'do' have an 80-transistor sized op amp circuit, for example - which
works - but for two reasons it's too much for me.
1. It is way too much to lay out for my hand-editing purposes
2. It is way too complicated for me to understand what's happening at
every node

I realize this is an unusual request (as most people simply size their
own schematics based on topologies) - but I'm just looking for the
perfect circuit to learn and understand for myself (and then teach my
young son).

There must be a simple sized cmos analog schematic out there ... I just
need to find it.
 
On Mar 25, 2:35 am, "Martin C." <martincella...@nospam-gmail.com>
wrote:
I am not an IC designer but I would like to, for fun, simulate and lay
out a circuit by hand that I can actually understand.

To get a head start, where do you suggest I find a small (ten, maybe
twenty transistors) sized circuit that I can actually understand (being a
business major)?

I found plenty of unsized circuits - which are, in reality, topologies
with missing parts - but - I was hoping to start with a working cmos IC
circuit that works out of the box so that when I simulate it, I could
learn what it is doing - and - so that I could begin to lay it out based
on the actual lengths and widths in the simulated schematic.

Is there a web-available source for very simple sized analog schematics
for learning purposes (i.e., something more than just a digital inverter
block, e.g., an analog op amp, band gap, comparator, vco, pll, etc.)?
Click to expand...
You might be interested in trying the Cypress PSOC devices. They also
include a microprocessor but have analog building blocks on chip. The
tools are free and I believe they have some level of simulation. Or
if you get really hooked you can buy an eval board and try building
your circuit and testing it.

Rick
 
On Sun, 25 Mar 2012 15:14:28 -0700, rickman wrote:

You might be interested in trying the Cypress PSOC devices.
Click to expand...
I did find 'some' simple analog circuits at the various edu sites but not
yet a simple sized schematic of general analog use ...

Here's what I have ... so far ...

This layout reference doesn't have sized schematics:
http://ims.unipv.it/Microelettronica/Layout02.pdf

This paper has a CMOS bandgap reference, where maybe I can figure out
sizes:
www.aicdesign.org/SCNOTES/2010notes/Lect2UP010_(100324).pdf

Or this one has a voltage reference that I might be able to simulate:
http://www.ee.nchu.edu.tw/Pic/Writings/677_01705059.pdf

This seems to have a sized schematic of reasonable simplicity:
http://weble.upc.es/rfcs/Material/Labs/RFCS_LAB1.pdf

This paper seems to have transistor sizes for a Miller amplifier:
http://www.see.ed.ac.uk/~s0571365/Files/Articles/Analog/Design/_Analysis%
20and%20design%20of%20amplifiers%20and%20comparators%20in%20CMOS%200.35um%
20technology_Cortes03.pdf

This seems to have opamp sizes:
http://kazus.ru/nuke/modules/Downloads/pub/196/0/OpAmp-Final_cadence.pdf
 
Does this ten-transistor CMOS MOSIS opamp test design look like a
reasonable first design (with sizes) to capture, simulate, layout, &
extract parasitics, and then re-simulate?

http://picturepush.com/public/7908714

That design is taken from this document:

http://www.asee.org/documents/sections/middle-atlantic/spring-2008/02-
Design-Simulation-and-Testing-of-MOSIS-Fabricated-CMOS-Operational-
Amplifiers-for-Class-Projects-in-an-Analog-IC-Design-Course.pdf
 
Here's another op amp with transistor sizes ...
http://jennisjose.webs.com/operationalamplifiers.htm
 
This two-stage op amp with an n-channel input pair circuit looks very
nice as a beginner simulation & layout project:
http://s.eeweb.com/members/neil_tsai/projects/2011/03/22/
CMOS_OpAmp-1300771784.pdf

They designed a two-stage CMOS operational amplifier with low power
dissipation and high gain in the AMI C5N 0.6Îźm process technology.
 
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