AnsweredAssumed Answered

No DC convergence with HB Simulation for SDD

Question asked by LHFT on Jul 8, 2004
Latest reply on Jul 13, 2004 by ddshark
I have to implement in ADS a component that is defined as voltage across this component depending on charge in this component: V=V(q). In reality V(q) could not be solved for q analytically.

I used a SDD 2-port as follows; in this simple example there is V=q**a:
F[2,0]=-U+q**a (hoping that this equation is numerically solved for q)
with the synonyms U=_v1 and q=_v2; a is constant.
Port 2 is attached with a resistance of 1e+18 Ohm, so it acts as an open.

With a>0 the error message is as follows:
Matrix is singular (probably detected at port 2)

With a<0 the error message is as follows:
Warning detected by HPEESOFSIM in `X1.SDD2P1' during DC analysis `HB1'.
SYM warning: Negative x in x**y.
Complex values not supported.
Error detected by HPEESOFSIM during DC analysis `HB1'.
No DC convergence.
To search for a more robust convergence algorithm,
set ConvMode=1 on the DC analysis and perform the DC
simulation again.  This will cause the simulator to vary the convergence parameters and report which parameter setting produces the fastest convergence.

What's wrong here?
Is there another way to implement this component?

Can anybody help me?
Thank you.