The most significant changes are the BJT model and "binning".
New features:
1. BJT model.
2. "Binning" for all MOS models.
3. Internal element: non-quasi-static poly-capacitor. (needed by BJT).
4. Enhancements to the data structures and model compiler to support
binning in general.
5. A line prefixed by "*>" is not ignored, in spite of the fact that
"*" usually begins a comment. This is a deliberate incompatibility
with Spice. If you prefix a line by "*>" it will be interpreted as a
non-comment in Gnucap, but a comment in Spice.
6. Circuit line prefixes of ">" and command prefixes of "-->" are
ignored. This is so you can copy and paste whole lines, without
having to manually remove the prompt string.
Changes that may or may not be improvements.
1. It is not the default to include stray resistance in device models.
The option "norstray" will revert to the old behavior. This is only a
change to the default value of "rstray".
Significant internal changes:
1. The internal element non-quasi-static poly-capacitor actually
works. It is used by the BJT model, and will eventually be used by
MOSFET models.
2. There are now two poly_g devices: "CPOLY_G" and "FPOLY_G". There
are interface differences that impact modeling. Previously, there was
only one, which is equivalent to the "FPOLY_G".
GnuCap is a general purpose circuit simulator. GnuCap was
formerly known as ACS. GnuCap performs nonlinear
dc and transient analyses, fourier analysis, and ac analysis
linearized at an operating point. It is fully interactive and
command driven. It can also be run in batch mode or as a server.
The output is produced as it simulates. Spice compatible models
for the MOSFET (level 1-7) and diode are included in this
release.
Since it is fully interactive, it is possible to make changes and
re-simulate quickly. The interactive design makes it well suited
to the typical iterative design process used it optimizing a circuit
design.
Unlike Spice, the engine is designed to do true mixed-mode
simulation. Most of the code is in place for future support of
event driven analog simulation, and true multi-rate simulation.
If you are tired of Spice and want a second opinion, you want to
play with the circuit and want a simulator that is interactive,
you want to study the source code and want something easier to
follow than Spice, or you are a researcher working on modeling
and want automated model generation tools to make your job easier,
try GnuCap.
