I’m planning to incorporate a header-type male connector carrying a signal (up to ~50MHz) and extend that signal to an SMA connector. What’s the optimal approach for this? I’m concerned about avoiding unterminated stubs, and I’m wondering if there’s a recommended PCB layout strategy or if I should consider using a mux. Any advice would be appreciated.
Ensure that the characteristic impedance of the transmission lines matches across the entire signal path. This includes the traces on the PCB and the connectors (header and SMA). Consistent impedance helps prevent signal reflections.
Maintain a continuous and uninterrupted signal path from the header to the SMA connector. Avoid sharp bends, vias, or changes in trace width that can introduce impedance variations.
Consider implementing proper termination techniques. You can use resistors at the end of the transmission line to match the impedance and avoid signal reflections. The resistor value should be equal to the characteristic impedance of the transmission line.
Keep stub lengths as short as possible. Stubs can act as impedance mismatches and lead to signal reflections. If you’re using a multiplexer, ensure that it doesn’t introduce more stubs.
If you are using aa 2 pin header then it’s pretty easy. Just place the header on top of the rf trace going to the SMA.
Using a pin header, you could add a removable jumper/0-ohm resistor right in the signal path to the SMA.