eldo_user

Examples
Example 21—Post-Layout Simulation using DSPF
Example 21—Post-Layout Simulation using
DSPF
Netlist file: dspf_backannotation.cir
Additional files: dspf_opamp_follower.dspf and ./dspf_opamp_follower.models/lib.eldo.
This example shows how to import a .dspf file containing layout parasitics. Using .ALTER
statements, several simulations with different degrees of backannotation can be overlapped and
compared. The circuit is a 2-stage opamp, connected in follower mode.
Summary of Eldo commands used in this example:
• .LIB—Library file.
• .DSPF_INCLUDE—DSPF file inclusion.
• .ALTER—Simulation rerun.
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
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