eldo_user

Examples
Example 23—Parametric Sensitivity Analysis
signal). The .SENSPARAM command computes the absolute and relative sensitivities of the
overshoot to the MOS geometries (see .SENSPARAM statement in this netlist).
Notice that .SENSPARAM is a “brute force” sensitivity analysis (it uses simple numerical
differences) and thus is less efficient as the duration of the analysis and/or the number of
parameters increase, but is applicable to any type of circuit and analyses.
Note
The circuit in this example is similar to that in Example 21—Post-Layout Simulation using
DSPF.
Summary of Eldo commands used in this example:
• .LIB—Library file.
• .SENSPARAM—Parametric sensitivity analysis.
• .EXTRACT—Extract characteristics from the simulator results.
Netlist Explanation
.LIB key=MOS
.LIB key=MOS_33
./dspf_opamp_follower.models/lib.eldo TT
./dspf_opamp_follower.models/lib.eldo TT_33
The above lines define the location of the model libraries to be included.
Vin IP GROUND DC 0V PULSE -0.6 0.6 10n 1n 1n 250n 500n
The above line specifies the opamp is connected with the positive input (IP) driven with a pulsetype
signal.
.tran 1n 500n
The above specifies a transient analysis is to be performed lasting 500ns with a plotting
increment of 1ns.
.option eps=1e-8 hmax=1n simudiv=0
The above line specifies a high accuracy is required to catch the details of the overshoot
waveform.
.PROBE I V
The above line specifies all current and voltage signals to be probed.
.plot tran v(ip) v(op)
The above line specifies that voltage/time plots should be performed of the input and output
voltages at nodes ip and op respectively.
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Eldo® User's Manual, 15.3