Hello,

In my design I need to do long transition simulation and control 2 nodes A and B.
In working mode that interests most of the blocks conected to A and B are in powerdown,
but influence nodes A and B by their impedances.

If I generate full netlist, simulation will continue several days.

So, I want to replace non-functional blocks by verilog-A models.
For it I need to characterize theirs input impedances. Eldo allows this possibility, providing so-called
"PORT"-feature, that permits to extract Z, X, Y - parameters. But unfortunately, documantation isn't clear.

My task is as follows. I have blackbox with only interface pin AAA. It has complicated architecture,
but finally inside there is connection to ground. I want to extract its Z parameters. What could be my setup.
I tried with following one (very simple), trying to measure the value of resistor.

Code:

*--------------- Z-parameter extraction test
Vin	in	0	0	AC	1
R1	in	0	500
*R2	out	0	500
*C1	out	0	1n

.AC DEC 1	10	100000
.plot AC	VDB(OUT)

V1	in	0	iport=1	rport=50
*V2	out	0	iport=2 rport=50

.plot	ac YR(1,1)
.print	ac YI(1,1)
.Ffile Y SINGLELINE test_param_y.par Hz ri

.plot	ac ZR(1,1)
.print	ac ZI(1,1)
.Ffile Z SINGLELINE test_param_z.par Hz ri

.plot 	AC SR(1, 1)
.print 	AC SI(1, 1)
.Ffile S SINGLELINE test_param_s.par Hz ri

.end 

File test_param_y.par looks like
Code:

! Data from zparam_extract_test
# HZ Z RI  R 5.000000E+02
!
1.0000000000000000E+01 0.0000000000000000E+00 0.0000000000000000E+00
1.0000000000000003E+02 0.0000000000000000E+00 0.0000000000000000E+00
1.0000000000000005E+03 0.0000000000000000E+00 0.0000000000000000E+00
1.0000000000000007E+04 0.0000000000000000E+00 0.0000000000000000E+00
1.0000000000000000E+05 0.0000000000000000E+00 0.0000000000000000E+00 

Maybe somebody did it already in Spectre. How setup should be done?
Thanks in advance.

Pavel.