I have several questions regarding specifications in the data sheet.
Modulation bandwidth in Table 2 says 500MHz - is this RF or baseband bandwidth?
Table 15, for pin 7 talks about a balun tuning inductor for balun optimization but there is no other reference in the data sheet. What is this and what is the optimization? Its mentioned also in Table 9. I see values of 0.1uF and 15nH in series with pin 7 on the eval card.
Is there any input return loss data available for the ADRF6821?
Does varying the digital attenuator have any effect on IQ image rejection?
On page 28 you discuss the 60 ohm output impedance (10+25+25 = 60). What is the penalty of using 45 ohm resistors instead of 25 ohms for a better match into 100 ohms (10+45+45 = 100)?
I'm looking at substituting this ADRF6821 in an existing design that uses the obsolete ADRF6820. I use the internal LO in both cases. My reference freq is ok (38.4M) with the new part and my freq range falls within the spec (950 to 2450M). My RF BW will be approx 30MHz.
Is there anything I need to be aware of in changing from one part to the other? I do see the gain is higher by some 8 to 9dB. Are there other areas where I should be concerned?