Here are the basic steps when approaching a balun and ADC matching network design in
the gigahertz region, in order to prevent your next matching effort from being
bandwidth-hampered:
- Choose a balun or transformer that has some bandwidth overage for your
particular application.
- If HD2 is important to your frequency application, choose a balun with ≤5
degrees of phase imbalance.
- A simplified input network can provide the initial placeholders required in most
matching efforts when using a balun or amplifier and ADC.
- You may not need every component listed, but initially they can be beneficial,
as it is not possible to capture all board layout and PCB parasitics in
simulation.
- Understand the trade-offs that can affect your bandwidth performance. Some of
these trade-offs can affect the linearity performance of the ADC.