AnsweredAssumed Answered

ADF4360-9 spurs -55 dbc

Question asked by V_G on Jun 25, 2015
Latest reply on Jul 30, 2015 by V_G

I use ADF4360-9 as a heterodyne at freqs 125...140 MHz (step and PFD freq = 25 kHz).

Ref = 55700 kHz  (R = 2228),shematic as recommended in ADIsimPLL, both inductors on pins 9,10 = 136 nH (100 nH + 36 nH LQW18A), Loop filter CPP_2C.

Spurs at freqs 139125...139450 kHz (N = 5565...5578) are about -55 dbc.

At 139125 spurs are on 250 kHz from carrier (both sides),

At 139450 spurs are on 425 kHz from carrier (both sides).

All frequencies outside the band 139125...139450 are OK, spurs < 70 dbc.

Can anybody test this situation on EvBoard?

Outcomes