How to use ".LIN analysis" in HSPICE

[engrvip]

How can I use .lin analysis in HSPICE to measure the impedance or transimpedance using Z parameters?

For .lin analysis "port" element are required to be used at the nodes where 2-port parameters need to be calculated. ANd this port element needs the value of "resistance" and "impedance" to be pre-defined.

My doubt is regarding how to define these resistance/impedance value for a port element during 2-port network analysis using .LIN analysis in HSPICE?

Thanks
Vipul

 

[erikl]

You just need to define an impedance value for a port, and only if you want to change the default value of Z=50Ω.

See e.g. the HSPICE® User Guide: Simulation and Analysis, chap. 17: Linear Network Parameter Analysis

 

[engrvip]

But what should be that impedance value I need to put in port element.

For example if I want to measure the output impedance of an Opamp then is it OK to work with impedance value of 50Ohm . What does this impedance / resistance value required by the port element signifies ????

 

[erikl]

What does this impedance / resistance value required by the port element signifies ????

For the input port: the output impedance of the driver for this input.

 

[engrvip]

For the input port: the output impedance of the driver for this input.

And what about the output port ??? In case of measuring output impedance of opamp , what value should I us of impedance in output port ??

 

[erikl]

If you just want to measure the output impedance, it's much simpler to add a unit current source (1A ac) between output and GND, no input signal, then run an .ac analysis and plot output voltage vs. frequency, this directly gives you output impedance vs. freq. (kV ≘ kΩ).