Re: can anybody tell me why nanosim simulation gives out ZERO current?

walala wrote:
> one VHDL program, used synopsys dc to synthesize and then used se
> place&route and extract the netlist, now use nanosim to simulate:
>
> A large number of warnings generated:
>
> WARNING:NanoSim:0x2110f525:Negative bulk-drain bias: element M3643,
> vbs=-0.400418... at 31.86ns ...
>
> what is the problem?

you can ignore this warning.

> why the simulated current is ZERO and when I use awaves to see the
> waveforms, all output waveforms are zero?

what current are you expecting? You have to set the right precision
for printing the current.

> ------------------------------------------------------------
> Final result:
>
> Block: total
>     Number of nodes in block            :  199
>     Number of elements in block         :  526
>     Number of block supply nodes        :  0
>     Number of block ground nodes        :  0
>     Number of block biput nodes         :  16
>     Number of block input nodes         :  0
>     Number of block output nodes        :  0
>     Number of block stages              :  1
>     Number of block partial stages      :  0
>
>     Average supply current              :  0.000000 uA
>     RMS supply current                  :  0.000000 uA
>
>     Average input current               :  0.000000 uA
>     RMS input current                   :  0.000000 uA
>
>     Average output current              :  0.000000 uA
>     RMS output current                  :  0.000000 uA
>
>     Average biput current               :  23.848912 uA
>     RMS biput current                   :  164.434740 uA
>
>     Average block power                 :  11.637640 uW
>     RMS block power                     :  360.975686 uW
>
> Simulation time resolution                      : 1.000e-02 ns
> Number of PWL matrix solutions                  : 1399
> Number of PWL MOS model lookups                 : 228412
> Number of time steps                            : 398
> Number of iterations                            : 0
> Number of rejected time steps                   : 0
>
> Global simulation parameters used:
>
> SPD            0.25V     ASPD            0.1V
> SIM_DESV       0.25V     SIM_AESV      0.125V
> VDS_MIN  0.000369011V     AVDS_MIN      1e-08V
> SSC (steady state current)         0.1uA
> SUBI (subthreshold current)          1uA
> DC CURRENT                           1uA
>
>               14.0 real        2.0 user        0.0 sys
>
>
> No errors reported in the .err file (output.err)