Noise modeling of opamp in frequency domain

[ramesh]

Hi,

I built an ideal opamp model (using ideal VCVS, resistors, caps
etc).

I have obtained a noise file from an amplifier (freq-noise voltage
pairs for frequencies sweep from 1 -> 10 Mhz) using cadence noise
analysis.

I want to include this noise (as frequency-value pair) at input of the
ideal opamp, and would like to observe the integrated noise @ output.

There is a way to include the noise (time-value pair) as a file in
transient domain (as vsource,vpwlf). However, I would like to include
the noise as frequency-values pair.

Appreciate if anyone could throw some light on this.

Regards,

Ramesh

 

[andrewb]

On Wed, 5 Dec 2007 16:43:13 -0800 (PST), ramesh
<rameshprakash@gmail.com> wrote:

Hi,

I built an ideal opamp model (using ideal VCVS, resistors, caps
etc).

I have obtained a noise file from an amplifier (freq-noise voltage
pairs for frequencies sweep from 1 -> 10 Mhz) using cadence noise
analysis.

I want to include this noise (as frequency-value pair) at input of the
ideal opamp, and would like to observe the integrated noise @ output.

There is a way to include the noise (time-value pair) as a file in
transient domain (as vsource,vpwlf). However, I would like to include
the noise as frequency-values pair.

Appreciate if anyone could throw some light on this.

Regards,

Ramesh

From "spectre -h vsource"

48 noisefile Name of file containing excess spot noise
data in the
form of frequency-noise pairs.
49 noisevec=[...] V^2/Hz
Excess spot noise as a function of frequency
in the
form of frequency-noise pairs.

Voltage sources support a noisefile giving noise versus frequency
pairs.

Or you could implement the model using Verilog-A - which also allows a
similar approach for modeling noise.

Regards,

Andrew.