Hi guys,

Can you  help me to deal with this simulation error, I use Hspice to simulate. all the warning and error are following:

**warning** effective csat(is) =  100.0000m  is too large in diode        0:d2              


**warning** effective csat(is) =  100.0000m  is too large in diode        0:d3              

**warning** rs for      1:d3               limited to   1.000E-05


**warning** mosfet device       1:m1       cdsat is too small at temperature   25.000    
value= 1.00000E-32,cdsat reset to epsmin


**warning** mosfet device       1:m1       cssat is too small at temperature   25.000    
value= 1.00000E-32,cssat reset to epsmin



**warning** conductance of    0.            on node     1:5                iter=  12

**diagnostic** rebuilding matrix with pivot option


**diagnostic** rebuilding matrix without pivot option


**diagnostic** dc convergence failure,
resetting dcon option to 1 and retrying


**diagnostic** dc convergence failure,
resetting dcon option to 2 and retrying.

no convergence with standard algorithm,  trying damped pseudo-transient

 *** initial damped pseudo transient completed. ***
 *** final try started ***

**warning** This was a difficult operating point.
            You can speed up your simulation by specifying:
            .OPTION CONVERGE=1
**error**  internal timestep too small in transient analysis

         time =  5.36237E-09;  delta =  1.90735E-15;  numnit =   335

Best Regards
Jay

I would suggest check the dimention of the diodes. If you have m^2, it may explain many things...

If all is OK, try to use PWL for you supply. Start with the 0 and gradually rise it to the VDD voltage.