ADF4360-6 Theta Jc, ThetaJb, Theta Ja

Question Could you please provide me the theta JC for the ADF4360-6 Answer The Simulated Thermal data available for the 24ld 4x4x0.85mm LFCSP with 2.3mm exposed paddle, is as follows; Theta JC: Paddle Soldered: 10.8 C/W Paddle not soldered: 10.8 C/W Theta JA: Paddle soldered: 57.4 C/W Paddle not soldered: 93 C/W Theta JB: Paddle soldered: 35.5 C/W Paddle not soldered: 64.8 C/W

ADF4360-6: harmonic and spur issue

Question 1. When the output divider by 2 is off, the second harmonic amplitude is around 15dBc (the ADF4360-6 show the typical value is 20dBc). But when they turn on the internal output divider on the ADF4360-6, the 3rd harmonic is amplitude is very close to the main frequency (~-5.6dBc).Does this is the internal VCO and output divider limitation or not. Because we try to use the ADF4360-6 as the mixer for GSM 900MHz/1800MHz repeater. The result can not meet specifications. 2. The Spectrum of the spurs shown the spurs performance is not good enough (58dBc only, the specification need at least 65dBc). This is relative to the output filter design. Any suggestions to improve it? Answer 1.This will happen, as the ADF4360-x parts will output a square wave when the divider is enabled, leading to high harmonic levels. A solution is to filter the output with an LC filter (described on datasheet) or use a bandpass filter, this will at least attenuate the unwanted 3rd harmonic. The ADF4360-7 at the same frequencies performs a little better (See graphs, with divide by two both enabled and disabled).(see file SCREN555 and SCREN556).2.Those levels have been seen on the silicon, although they seem a little high. If possible I recommend using the ADF4360-7, which will have considerably lower spur levels (See graph). The external inductor value needs to be approximately 1.6 nH - 2 nH. See attached plot from ADF4360-7. It performs better and takes lower current(see file SCREN554) .