@User it depends on the design of the amp. they can be matched fairly closely with the right architecture...or what is typically done is not to impedance match to 50 ohm on the output and just characterize it. Then the user can put a matching transformer or network externally. If it's feeding into a PA with a common source JFET input then you can match easily there. This last item would be the likely use as even with 20V swing, you can't push many watts through an asic that isn't designed as a power device. So you'd amplify your voltage up to 20V and output a low current then use a class AB power amp with a jfet input stage to boost the current