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ADRF6720 REFin spec

Question asked by petersk on Mar 4, 2017
Latest reply on Mar 9, 2017 by LKelly

There are some discrepancies on the data sheet for the ADRF6720 with respect to REFin. Page 8, absolute maximum for REFin shows -0.3 V to +3.6 V.  Figure 44 shows an AC coupled input. This doesn't seem possible to stay within the absolute maximum unless the signal is kept to +/- 0.3 V (0.6 Vp2p).  Page 24 says "to the REFIN pin, which is ac-coupled," which seems to correspond to the REFin absolute max ratings on Page 8 (if it's AC coupled internally). The specifications in that paragraph AND page 4 show the implemented max amplitude in dBm (4), which implies the user would AC couple the input externally. So... can someone provide any input on what the REFin signal SHOULD actually look like for the PLL to lock?  Currently I'm DC coupling into it ... is that going to break things?

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