I am evaluating the characteristic by using the evaluation board of Figure 60 in the ADL5382 datasheet.
I will use the device by the bandwidth from 10KHz to 40MHz.
To confirm the frequency response, I removed the transformer of T2 and T3 from the board.
Because the transformer doesn't support the frequency response.
Under such a condition, I evaluated the frequency response.
I expected a flat characteristic from DC to 40MHz.
But, when the signal of 0.5MHz was input, the output of Q signal attenuated 1.7dB.
In this board, why does a low frequency band attenuate?