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adl5380  Low-IF architecture

Question asked by KJH on Jan 25, 2012
Latest reply on Jan 30, 2012 by Qui



I want to use ADL5380 chipset for wideband receiver application having 36MHz BW.


And adl5380 datasheet says that "low-if image rejection is critical. a 90 degree shift to I or Q channel cancels the image. Phase and gain balance is critical"


1. in rf textbook Hartley architecture rejects image signal. so i guess a 90 degree shift of adl5380 datasheet is related to the harley achitecture. is that right?

2. Is that means that ADL5380 has a integrated 90 degree shift or should i attach the offchip 90 degree shift?

    If ADL5380 has a integrated 90 degree shift, which channel (i or q) linked to the 90 degree?

3. In my application, frequency range is from 2GHz to 6GHz. so i need switched 3 transformer baluns. Is there any simple way to make wideband balun?

4. Figure 86 and 87 describes adl5380 has a good image rejection at 2.5MHz, 5MHz, 7MHz Low IF. Is that possible to use 20MHz IF architecture without any pre-image rejection filter?