How the bandwidth is impacted by the load?

The bandwidth of electronic parts, like analog switches, is usually specified for a specific load, typically 50 ohm and 5 pF for example.

Now if I have an analog switch with a bandwidth of 1 GHz for a 50 ohm load, how the bandwidth change depending on the load? What appends for, say, a load of 1 kOhm? Is there a way to calculate or estimate the bandwidth for different load values?

Thanks.

(this is a follow-up of High voltage high bandwidth analog mux)

Answer

In the 1Ghz range the most important is load capacitance. The higher capacitance - the less bandwidth. With 1nF load you are likely go under 10 MHz bandwidth. So avoid long traces.

Resistive load - if it's too high (like 5Ohm) you can just get signal with lower amplitude or more distortion, but bandwidth is not that much affected. And 1kOhm will not hurt usually (unless there is some fancy load matching, which is unlikely).