AnsweredAssumed Answered

ADF4355-2 heat problem vs band setting

Question asked by freezees on Sep 7, 2016
Latest reply on Jan 9, 2017 by icollins

Dear ADI

We transmitted an 1830MHz signal through ADF4355-2 and have the following observation.

1. Enable ADF4355-2(fast lock) and start transmit at 1830MHz

2. Enable PA( board temperature rise up)

3. After 1~2min warm up base on the power of PA, the ADF4355-2 signal output become like this.

here's a video link

Record 2016 09 07 16 57 03 348 - YouTube 

4. Not every frequency has this problem

test with different frequency 915M and 910M fail - YouTube 

5. I know this problem has something to do with "band" setting ( register 11)

for example, the original setting Reg11 = 0x0061297B 

if I lower the band setting from 0x97 to 0x96 or lower, the problem gone.

On the contrary, if band set to larger like 0x98, the problem go worse.

the original band setting I got is from data read back AN1381.


My questions are

How does it happen?

Is there a temperature compensation in ADf4355-2?

thank you