About noise simulation in spectre

[Dmitriy Shurin]

I am simulating a pixel ,and I want to check output noise ,generated
by input noise of one of the transistors. As I understand I have to
define Input noise as a port but it does not allow me to select the gate
of this NMOS. Another question once I receive an output noise,
how can I receive a graph of input reffered noise?
Thank you


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[amit bansal]

Hi dmitry,

I have never used input reffered noise conecpt . But I know that
spectre is able to give noise contribution of each transistor , as
discussed in previous thread. BTW did u try to add a port component
from the analoglib library? I think u may add port at the gate of the
transistor.

regards
Amit

 

[Andrew Beckett]

On Thu, 29 Sep 2005 13:58:40 +0000 (UTC), "Dmitriy Shurin"
<shurin@bgumail.bgu.ac.il> wrote:

I am simulating a pixel ,and I want to check output noise ,generated
by input noise of one of the transistors. As I understand I have to
define Input noise as a port but it does not allow me to select the gate
of this NMOS. Another question once I receive an output noise,
how can I receive a graph of input reffered noise?
Thank you

If you want to measure input referred noise, you'll need a source of some
type at the input. This can be an isource, vsource, or port. However, if you use
a port, you'd need to have a matched input, because the noise is referred to the
source inside the port. Since the gate will have high input impedance, I don't
think it makes sense to use a port.

So, use a voltage source, and then specify the voltage source as your input
source.

This will then compute the output noise, and divide it by the gain from the
input source to the output, and give you the input referred noise - which you
can then plot via the Direct Plot menu.

A "port" is not the same thing as the terminal of a device - it's a specific
spectre component.

Best Regards,

Andrew.