Application Note AN-742

One page 4 of AN-742 the design example uses AD9236 input impedance values taken from a graph Fig.6 on page 3 (or tabulated S parameter data) and it appears to be interpretted as elements of a parallel equivalent circuit.

However AN-827 which elaborates on the method and displays exactly the same graphs states that the R &C elements in the plots are SERIES equivalents and gives a method to convert to the parallel equivalent circuit better suited for matching circuit design.

So although the general design outline in AN-742 is sound, the parameter values used appear to me to be inconsistent with the interpretaion given in AN-827.

Any comment on this greatly appreciated.

Hi George,

All the plots are of the parallel configuration.

Figure 9's X-axis is incorrect. It should be from 0 to 200MHz. Not 1000MHz. Sorry about that.

Regards,

Rob