User Guide

Chapter 3 Preparing a design for simulation
84
Missing DC path to ground
If for selected nets in your circuit you see this message in
the PSpice output file,
ERROR -- Node node_name is floating.
then you may be missing a DC path to ground.
Check for this
Are there any nets that are isolated from ground by either
open circuits or capacitors?
If so, then add a very large (for example, 1 Gohm) resistor
either:
• in parallel with the capacitor or open circuit, or
• from the isolated net to ground.
Example: The circuit shown below connects capacitors
(DC open circuits) such that both ends of inductor L2 are
isolated from ground.
When simulated, PSpice flags nets 2 and 3 as floating. The
following topology solves this problem.
Note
W
h
en ca
l
cu
l
ating t
h
e
b
ias point
solution, PSpice treats capacitors as open
circuits and inductors as short circuits.
Pspug.book Page 84 Wednesday, November 11, 1998 1:14 PM