User Guide

Chapter A Setting initial state
376
Setpoints
Pseudocomponents that specify initial conditions are
called setpoints. These apply to the analog portion of your
circuit.
Figure A-1 Setpoints.
The example in Figure A-1 includes the following:
Using IC symbols sets the initial conditions for the bias
point only. It does not affect the DC sweep. If your circuit
design contains both an IC symbol and a NODESET
symbol for the same net, the NODESET symbol is ignored.
To specify the initial condition, edit the value of the
VALUE property to the desired initial condition. PSpice
attaches a voltage source with a 0.0002 ohm series
resistance to each net to which an IC symbol is connected.
The voltages are clamped this way for the entire bias point
calculation.
NODESET1 is a one-pin symbol which helps calculate the
bias point by providing a initial guess for some net.
NODESET2 is a two-pin symbol which helps calculate the
bias point between two nets. Some or all of the circuit’s
nets may be given an initial guess. NODESET symbols are
effective for the bias point (both small-signal and transient
bias points) and for the first step of the DC sweep. It has
no effect during the rest of the DC sweep or during the
transient analysis itself.
IC1 a one-pin symbol that allows you to set
the initial condition on a net for both
small-signal and transient bias points
IC2 a two-pin symbol that allows you to set
initial condition between two nets
Pspug.book Page 376 Wednesday, November 11, 1998 1:14 PM