Q.
What is the input impedance to ground for the I and Q inputs of the AD8340, AD8341 and ADL5390 vector Modulators?
A.
These inputs connect to the bases of transistors. So the input impedance will be high and will consist of a resistive and capacitive component. Simulations show an impedance of about 23 megaohms in parallel with approximately 400 fF of capacitance from each input to ground.
