How to use ELDO at ECE/OSU

Why Eldo?

Eldo has some advantages, at least to me, against HSpice and Spectre. It has:

Transient noise analysis: It's a noise simulation in the time domain. We can do that in .AC statement, or in the frequency domain in other SPICE based simulator. That means all DC point is fixed and we can see the frequency response only.
ELDO repeats the transient analysis with and without noise. It shows RMS noise of the output in the time domain.
Switched Capacitor Macromodels: It has switch model, too. In a sense, we may use ELDO instead of SwitCap2. Also we can specify the on-resistance in that switch model and do the noise-simulation.
Differential Accuracy System in Mixed Mode Simulation: Imagine advanced data converters. It may have both analog and digital circuits. We don't need higher accuracy in the digital block very well.
Spectre has this mix-mode simulation feature, too, but not Hspice.

First step

You can read the ELDO manual with accrobat format:


%mgc_acro

MGC -> View Installed Bookcase -> Eldo Kernel Documentation Bookcase

In case the command mgc_acro doesn't work, you can read the manual directly using normal acroread command. The most important manual is eldo_ur.pdf in /nfs/stak/a1/mgc/anacad/documentation/

Then, read "Eldo User's Manual" first.
To enable ELDO, do this first:


source /usr/local/apps/mgc/libraries/mgc_hep/startups/startup.csh

It is easy to start with this command:


% esim

Tips

.probe: You can use .probe command in ELDO. This command meaning is the same as Pspice, not Hspice.
Remember the .probe command without parameters does NOT make probe data in Hspice. The .probe command without parameters DOES make probe data in Pspice and ELDO. Why? Don't ask me.
Also remember in ELDO, the maximum number of saving data is 50 in default. You should specify the number in option command if you want, like this:
.option limprobe=100
Xelga: The menu is a little bit tricky (to me).
The list of nodes are in:
Page -> Composition
Why can't I get *.hmp file when I set MBRUN=1?: You need MRUN option in .noisetran statement at the same time. Then you'll get *.hmp file but I don't know the meaning of *.hmp file because we have *.cou file to view it in Xelga.
I would like to print out noise values. How?: We can view it using Xelga, but there is no way to print out on a file right now. I confirmed Mentor on 1999/8/31. They're working on this problem.

Go to the top page.

Comments? Email to Testuya Kajita

Last modified: Wed Sep 08 13:12:09 1999