pseudo transient analysis in ADS

I simulate some circuit in ADs, which converged in DC analysis but failed to converged in pseudo transient analysis. Could someone give me some guide of the theory of pseudo transient analysis in ADS?

Thanks!

What kind of model you are using?., Transitor model?, capacitance model?, Diode model?,, etc

regards

It is not an ordinary component provided by ADS or some other company. It is a sdd_based model which is built by myself.