How to simulate the output resistance of a bandgap reference?

[abcyin]

Hi, all

Is there anybody who can tell me how to simulate the output resistance of a bandgap reference, I mean the output resistance of the current reference output,

we always use .sp analysis to detect the output resistance characteristic, and it needs to add input and output ports, but where to add the input port for the bandgap reference, it's a problem.

Thx in advance!

 

[hmsheng]

bandgap reference

Two ways:

1. Do AC simulation at the interesting frequency.
Add an AC current source at the output port and measure the AC voltage at output port, then calculate the voltage to current ratio.
2. Do one port S-parameter analysis.

Only small signal output impedance can be got with above 2 methods. If large signal output impedance is needed, you can run PSS or HB analysis samilar to the first way.

 

[analog_prodigy]

bandgap reference

Apply a test voltage at the bandgap output and measure the small signal current. The ratio gives you the ouput resistance

 

[siddharthshukla]

Re: bandgap reference

u can use the .TF comand instead and specify the nodes at which u want to check the resistance ,i n the chi file u can then get the transfer function along with the output resistance.