In the datasheet of AD9467-250, there are two Differential Transformer - Coupled input Configuration(Figure 51 and Figure 52). One is for Baseband Applications up to 150 MHz , the other is for IF Applications from 150 MHz to 300 MHz.
(1) If I want to design a broad band application that span from 1MHz to 300MHz, how should I design the input configuration ?
(2) ADT1-1WT is a 75ohm 1:1 transformer, but in Figure 51 and Figure 52 there is a note that indicate the impedance of the transformer is 50ohm("input Z=50ohm"). Why the input impedance for this transformer is 50ohm here?
(3) A single transformer is sufficient to transform a single-ended signal to differential signal. Why Figure51 and Figure52 use two-stage transformers?