ADRF6821 FAQ
https://ez.analog.com/rf/f/q-a/587931/adrf6821-board-not-connecting-to-ace-s-w-with-sdp-s
ADRF6821
Recommended for New Designs
The ADRF6821 is a highly integrated, dual radio frequency (RF) input, zero intermediate frequency (IF)/low IF RFIC receiver
with a quadrature demodulator...
Datasheet
ADRF6821 on Analog.com