CW305 Board Component


#1

Hi,
Could you please explain why the R31 (49.9 ohm) resistance is kept at the LNA (BGA2801) input, while the BGA2801 datasheet says that the device is internally matched to 50 ohms? Is it then not dividing the voltage by 2, which is not desired?

Thanks and regards,
Ron


#2

Hi Ron,

I don’t really have an answer, just hazarding a guess here (and there is a good chance I am wrong!) but the power source would be assumed to have a very low internal impedance, and so R31 would be used to bring the power source impedance seen by the LNA closer to 50 ohms?