Simulation for LNA IP3 and 1 dB com. point using SpectreRF

To Hello,

Whats are steps needed to use SpectreRF to simulate IP3, 1 dB compression point and S parameters on a 1.2 GHz inductive degeneration single-ended LNA?
Thanks.

T.P. Puah

You should use PSS analysis in SpectreRF with psin source while Amp(dBm) is changed in convenient limits. In this case you do SPSS ( Swept periodic Steady State ) analysis.
When you finished the simulation, SpectreRF automatically will introduce a choise for IPn and Compression points ( either output and output ) .
For LNa's , "Input IPn points ( such as IP3 and IP5 ) are important.

You may select the psin output port and find the behaviour.

Look at SpectreRF Simulation SPSS in User Manual ..

To Hello,

What are the best fi and f2 to choose for simulating a 1.2GHz LNA using SpecterRF.

T.P. Puah

closely spaced f1 and f2, such as 1 or 10 MHz. There is no best f1 and f2 to use, it is an arbitrary value.

To Hello,

In SpectreRF how do you obtain the frequency response of a LNA?
At present I can only think of using S21.
In a CMOS inductive degeneration LNA with a cascode output configuration and a single connected constant current bias, how can I ensure that my design have a flat frequency response?
Thanks.

T.P. Puah