AMS Convergence Problem

Discussion in 'Cadence' started by Debjit, Mar 25, 2010.

  1. Debjit

    Debjit Guest

    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.
     
    Debjit, Mar 25, 2010
    #1
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