4 Summary

To summarize, multi-GHz matching networks can be difficult and are not always straight forward. Hopefully this document provides good guidance on where to start as well as some of the pitfalls that can be encountered along the way. Make sure to choose a balun or transformer that is has some BW overage for your particular application. If HD2 is important to your frequency application, make sure to choose a balun with 5degrees or less in phase imbalance. Using the simplified input network above can provide all the initial placeholders that can be required in most matching efforts when using a balun or amplifier and ADC. In the end, you do not need every component listed, but initially these are nice to have, as you cannot capture all board layout and PCB parasitics in simulation. Lastly, understand the iterative tradeoffs that can have an effect on your BW performance. Keep in mind, some of these trades can also affect the linearity performance of the ADC as well. Although there is a lot to digest here, this paper provides the basics steps when approaching a balun and ADC matching network design in the GHz region, which can prevent your next matching effort from being BW hampered.