User`s guide

PSpice A/D-Equivalent Parts 6
-33
where MAXREAL is a PSpice A/D internal constant
representing a very large number (on the order of 1e30). In
general, the result of evaluating an expression is limited to
MAXREAL. Note that the output of the symbol can also be used
as part of the controlling function.
To create this device, you would first make a new symbol,
GDIV, based on the GMULT part. Edit the GDIV template to
divide the two input values rather than multiply them.
Lookup Tables (ETABLE and
GTABLE)
The ETABLE and GTABLE parts use a transfer function
described by a table. These device models are well suited for use
with measured data.
The ETABLE and GTABLE symbols are defined in part by the
following attributes (default values are shown):
ETABLE
TABLE (-15, -15), (15,15)
EXPR V(%IN+, %IN-)
GTABLE
TABLE (-15, -15), (15,15)
EXPR V(%IN+, %IN-)
First, EXPR is evaluated, and that value is used to look up an
entry in the table. EXPR is a function of the input (current or
voltage) and follows the same rules as for VALUE expressions.
The table consists of pairs of values, the first of which is an
input, and the second of which is the corresponding output.
Linear interpolation is performed between entries. For values of
EXPR outside the table’s range, the device’s output is a constant
with a value equal to the entry with the smallest (or largest)
input. This characteristic can be used to impose an upper and
lower limit on the output.
An example of a table declaration (using the TABLE attribute)
would be the following: