Problem with noise analysis in cadence?

[ngox]

I am trying to run Noise analysis of an amplifier in Analog Environment but am having trouble doing so. Normally the noise should be high at low freq (flicker noise) and then low at higher freq. However, I am getting a low noise at low frequencies and then a peaking at a fairly high frequency (around 12 GHz). I know this frequency shift normally applies to oscillators, but I have allowed my amplifier a phase margin of 61 degrees. Anyone have any thoughts on this? I am choosing Direct Plot -> Equivalent input noise.

 

[eld03]

What you expect is right to some extent of frequency. your freq of 12G is very high may be there is gain peaking at some point . It would be better to see integrated rms noise plot vs frequency it will provide better insight. Without actual circuit or ac gain plot it difficult to pinpoint.

 

[steadymind]

a snapshot of testbench would be useful without it we cant say if ur setup is right.