• To: mathgroup at smc.vnet.net
• From: Eckhard.Hennig at infineon.com (Eckhard Hennig)
• Date: Thu, 14 Mar 2002 19:51:22 -0500 (EST)
• References: <a6chgc\$dqm\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```hrh1818 at springnet1.com (Howard R. Hansen) wrote in message news:<a6chgc\$dqm\$1 at smc.vnet.net>...
> design software package for Mathematica.  Can anybody suggest a web location
> where a review may be found?  Or better yet what capabilities does Analog
> Insydes offer that Pspice doesn't?

The first and most obvious difference between any numerical simulator
(such as PSpice) and Analog Insydes is that the focus of the latter is
on *symbolic* analysis of analog circuits. That is, with Analog
Insydes you can compute transfer functions, poles and zeros, etc. of
analog circuits as symbolic functions of the circuit parameters (R's,
C's, gm's, ...).

integrated circuit blocks of industrial size symbolically. I have used
the tool successfully to calculate circuit characteristics such as dc
gains, poles and zeros, or PSRR for CMOS opamps with 30 ... 50 (and
more) MOSFET devices. The resulting symbolic expressions helped to
solve intricate stability and frequency-compensation problems which
were far too complex for manual analysis.

for pure simulation tasks, SPICE is the more efficient alternative.
However, in addition to solving for voltages and currents, you can use
systems of circuit equations for circuit parameters instead. Thus, in
circuit *design* problems as well.

BTW, a popular misunderstanding is that symbolic circuit analysis and
numerical simulation are alternative approaches to the same problem,
i.e. the precise prediction of the behavior of a circuit before it is
implemented in silicon. This is not true; symbolic analysis is not an
alternative but a complementary tool to numerical simulation.
Numerical simulation tells you quickly and precisely *that* something
is wrong with your circuit design whereas symbolic analysis tells you
*why*. So one should always use symbolic analysis as a qualitative
analysis tool in combination with a circuit simulator for design
verification.

Best regards,

Eckhard Hennig

# Disclaimer: the opinions expressed in this message are mine and
# may not represent those of my employer.

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