AMS Convergence Problem

Dear All,

I am extremely Sorry. I beg pardon humbly for not providing enough
info.
The details are given below.

1. Circuit Type: PMU Chip consisting of LDOs and Buck Converters
2. Simulation Result: Suceessfully simulated in Circuit Level using
Spectre and with Verilog-A and Verilog models using spectreVerilog.
3. Basically whenever I am trying to circuit in AMS (as I am gradually
switching from spectreVerilog to AMS following the AVUM workshop
manual included in the Cadence Distributino), it says that it is
trying to do homotopy = "dptran" but after some hour, it reports that
it failed to converge. I obtained convergence using homotopy =
"dptran" in spectreVerilog.
4. icfb Subversions: 5.10.41.500.6.141
spectre Subversion: 7.2.0.174.isr3
ncsim version: 08.20-s022
nchelp version: 08.20-s022
5. AMS used in ADE model. I don't feel comfortable in HED model.
6. I am using OSS irun based netlister and simulating in batch mode.
7. I am using Cadence in built connect modules.
8. The summary of simulation parameters are given as follows:
start = 0 s
outputstart = 0 s
stop = 1.5 ms
step = 1.5 us
maxstep = 30 us
ic = all
skipdc = no
reltol = 10e-03
abstol(V) = 100 uV
abstol(I) = 100 pA
temp = 25 C
tnom = 27 C
tempeffects = all
errpreset = moderate
method = trap
lteratio = 3.5
relref = sigglobal
cmin = 100 aF
gmin = 1 pS
The above simulation setup was fine for me in spectreVerilog.

Thats all the info I have with me.

Please provide me some suggestions.

Thanks and Regards !!!!
Cheers !!!

Debjit.