how to simulate the noise of op amps?

[wonbef]

hi,all,

if use spectre simulator, how to simulate the noise of op amps? need your helps!

Thanks in advance.

all best wishes,

 

[SkyHigh]

Add AC voltage source in series or current source in parallel.

 

[extraord]

there is noise or pnoise optional analysis in spectre analog artist

 

[wonbef]

hi, extraord, in noise analysis, how to specify parameter options? thanks in advance.

 

[tony_wu_ad]

if you use the simulation of spice
you can use command
.noise
the spice can give the noise voltage

Added after 2 minutes:

before use the command of .noise
must use the command of .ac

 

[extraord]

you can select the input from schematic or type \vin in blank.
and also the output like \voutp \voutn.
also the noise frequency such as 20~20kHz

for more you can search the doc in www.designers-guide.org.

 

[xwcwc1234]

How about in Hspice, and how to plot the noise waveform ?

 

[mircea]

Hi
In Spectre you have the Noise analyses - you have to place a port on the input and sweep a variable (probably frequency in your case).
You can also do this by runing a PSS analyses - this is more complex and you can apply 2 tones on the input.
You should be able to find tutorials and examples in Cadence Help!
Good luck!

 

[wonbef]

many thanks to all above!

if place a port on the input, how to fill out the parameter option? thanks.

 

[wonbef]

i had a try! in spectre, the result of simulation of using noise analysis between add a AC source and place a port on the input are different. i don't know anything wrong. if place a port on the input, how to fill out the parameter option? thanks.

regards

 

[starcoming]

Who can tell me which kind of noise it is that is siumulated by the command .noise?
Thermal or flicker?
Thanks!