CTT
Newbie level 6
Hello,
There is a subject that has been annoying me for a while. Switched-mode PA such as class D, E are structures that have theoretically 100% drain efficiency capability. However the output impedance is not matched to the load impedance which seems normal because of the loadline theory that predicts that optimum operation is reach with a particular load impedance value.
That may work fine with a broadband load, but I was wondering what would happen when connecting a SAW like filter that typically require impedance matching (usually 50 Ohms) ?
For example consider an open collector output driving a SAW filter by mean of a LC macthing network. Theoretically we may optimize the drain efficiency but however generate lots of reflection at the SAW connection due to the non matching !
Is my reasonning correct ?
CTT
There is a subject that has been annoying me for a while. Switched-mode PA such as class D, E are structures that have theoretically 100% drain efficiency capability. However the output impedance is not matched to the load impedance which seems normal because of the loadline theory that predicts that optimum operation is reach with a particular load impedance value.
That may work fine with a broadband load, but I was wondering what would happen when connecting a SAW like filter that typically require impedance matching (usually 50 Ohms) ?
For example consider an open collector output driving a SAW filter by mean of a LC macthing network. Theoretically we may optimize the drain efficiency but however generate lots of reflection at the SAW connection due to the non matching !
Is my reasonning correct ?
CTT