Hi,


first you need to know a few things.

1) do you want voltage gain or power gain?
2) what is the source impedance coming from the PLL? for example, 50 ohm.
3) what is your load impedance?

Power is V²/R. If you don't want power gain, you can still get voltage gain by changing R. This is the matching network approach. When you design your matching network, you will need to use a low-pass filter configuration. However, the matching network voltage gain will be limited by the source and load impedance since the input power must be equal to the output power. Therefore, you may not be able to do the matching network approach anyway.

If you describe your application, you will get a better answer. For example, is your PLL on the same die as your design? Where is it used (a mixer for example)?


regards,
Aaron

Hi adelaid,


the approach isn't necessarily wrong, but maybe it could be improved. Unfortunately, its impossible to know without more info. For example, why do you need voltage gain? The PLL usually provides a good signal swing. What kind of output power do you need? Is the output power spec just for testing purposes? What is the operating frequency? Since you say you need a sinusoid, maybe you have a harmonics spec?

When you have multiple stages of amplification, the distortion primarily comes from the later stages. So I would keep my filtering closer to the end of the chain. You could use a matching network to improve S22 if you really need to, but whether you need to or not depends on your application. The matching network can be of the low-pass type so that you can get your sinusoid.


regards,
Aaron