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Question about impedance matching between ADL5380 IQ output and AD8366 input

Question asked by Matt1012 on Mar 22, 2016
Latest reply on Mar 22, 2016 by jdobler


According to the datasheet of ADL5380:

The baseband outputs QHI, QLO, IHI, and ILO are fixed impedance ports. Each baseband pair has a 50 Ω differential output impedance

WHILE from the datasheet of A8366, the Differential Input Impedance of IPPA, IPMA, IPPB, IPMB pins are 217 ohm,

When ADL5380 & AD8366 were designed in AD-FMCOMMS1-EBZ board, I suppose there shall be a transformer (impedance ratio 4:1 like TC4-1W)

between, but they were connected only with a reserved lump filter replaced with 0ohm resistors in series parts.


Will this be fine?


Please advise, thanks.