User`s guide

6
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2 Analo
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Behavioral Modelin
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Overview of Analo
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Behavioral Modelin
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The Analog Behavioral Modeling (ABM) feature provided in
PSpice A/D allows for flexible descriptions of electronic
components in terms of a transfer function or lookup table. In
other words, a mathematical relationship is used to model a
circuit segment so the segment need not be designed component
by component.
The symbol library contains several ABM parts that can be
classified as either control system parts or as PSpice A/D-
equivalent parts. See Basic Controlled Sources
on page 6-46 for
an introduction to these parts, how to use them, and the
distinction between those with general-purpose application and
those with special purpose application.
Control system parts are defined with the reference voltage
preset to ground so that each controlling input and output are
represented by a single pin in the symbol. These are described in
Control System Parts
on page 6-7.
PSpice A/D-equivalent parts reflect the structure of the
PSpice A/D “E” and “G” device types which respond to a
differential input and have double-ended output. These are
described in PSpice A/D-Equivalent Parts
on page 6-28.
The Device Equations option (described in the online MicroSim
PSpice A/D Reference Manual) can also be used for modeling of
this type, but we recommend using the ABM feature wherever
possible. With Device Equations, the PSpice A/D source code is
actually modified. While this is more flexible and the result
executes faster, it is much more difficult to use and prone to
error. In addition, any changes made to source code must be
reapplied whenever a PSpice A/D update is installed. Parts built
using ABM can be used for most cases of interest, are much
easier to use, and are unaffected by PSpice A/D updates.