Nexxim Transient Analysis
Options
Option
|
Default Value
|
Description
|
abstol
|
1e-9
|
Absolute error tolerance for currents
(Amps)
|
accurate_points.num
|
0
|
Force transient analysis to place
timepoints at N equidistant points (simulate N events)
|
accurate_points.start
|
0.0
|
First accurate point
|
accurate_points.stop
|
0.0
|
Last accurate point
|
alpha
|
0.0
|
Minimum conductance of the resistor
placed in parallel with each branch (mho)
|
beta
|
0.0
|
Minimum conductance of the resistor
placed between each node and ground (mho)
|
errpreset
|
None
|
Overrides parameter defaults for
speed/accuracy tradeoff. See Table 4 in this topic.
|
limiting
|
1
|
1=allow limiting on Newton steps
|
limiting_step
|
0.3 for nonlinear circuits.
Very large (disabled) for linear circuits.
|
Maximum absolute voltage update
allowed per N-R iteration (Volts)
|
max_frequency
|
50e9
|
Maximum frequency resolved by transient;
used for S-parameters
|
maxiters
|
10
|
Maximum number of Newton-Raphson
iterations for each timestep
|
method
|
trap
|
Integration method (parentheses
show synonyms for methods):
trap (trapezoidal)
gear (bdf2)
ndf2
|
NOISEFMAX
|
0
|
The highest frequency to analyze
for pseudorandom noise. Must be non-zero to enable transient noise analysis.
Maximum transient timestep will be set to 1/NOISEFMAX.
|
NOISEFMIN
|
|
Lowest frequency to analyze for
noise. Below NOISEFMIN, noise power density is constant.
1/NOISEFMIN must be less than the transient analysis stoptime. Not
used currently.
|
NOISESCALE
|
1
|
Scale factor
|
NOISESEED
|
0
|
Random number seed. Using the same
seed generates the same set of random values
|
NOISESTART
|
0
|
Noise start time
|
NOISETMIN
|
0
|
Noise minimum transient step. Not
used currently.
|
num_frequencies
|
500
|
Number of frequencies resolved
by transient plus DC; used for S-parameters
|
outputstart
|
0.0
|
Time to start saving results to
a file
|
relref
|
allocal
|
The RELREF argument controls
how the norms are computed for the delta check, function check, and
LTE checks. Point-local means the norm is local to the signal
and to the time step. Local means the norm is local to the signal
but considers the maximums over all time-steps. Global means
the norm is global for the entire circuit over all time-steps. The settings
for relref are:
pointlocal = Point-local for delta, function,
and LTE
alllocal = Local for delta, function, and
LTE
sigglobal = Local for function, global for
delta & LTE
allglobal = Global for delta, function, and
LTE
|
reltol
|
1e-3
|
Relative error tolerance for currents
and voltages
|
read_state
|
None
|
Read initial state from the specified
file
|
result_as_initial_guess
|
1
|
1=Use of the result from each step
in a sweep as the initial guess for the next sweep step.
|
sig_storage_off
|
0
|
1=Skip time domain probe data storage
|
skipResult
|
0
|
By default, transient results are
stored into the SDF file. For the Eye Scope, setting skipresult to 1
allows the user to see the eye without storing all the data.
WARNING: Nexxim does not check that there is an
Eye Scope present, risking loss of data.
|
step
|
None
|
Suggested transient step size
|
stop
|
None
|
Stop time
|
stop_pwl_times
|
1
|
0=Transient will not stop at the
data points in any PWL source
1=Transient will stop and start backward Euler at
every point specified in all PWL sources
2=Transient will stop at every data point in all
PWL sources, but will maintain the current integration order
3=Transient will stop only at data points that deviate
from the extrapolation using the previous two points by more than the
reltol and abstol specified for transient
|
rmax
|
10
|
Factor for calculating maximum
timestep
|
tmax
|
stoptime/100
|
Maximum step size
|
trtol
|
7.0
|
Ratio of transient analysis tolerance
to Newton-Raphson tolerance, for timestep calculation
|
update_jacobian_period
|
3
|
Number of Newton steps per Jacobian
update
|
write_final_state
|
|
Write the final values of node
voltages to specified file
|
write_initial_state
|
|
Write the initial (DC) values of
node voltages to specified file
|
vntol
|
50e-6
|
Absolute error tolerance for voltages
(Volts)
|
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