Hand touch a crystal to make it start-up to ocsillate.

[ken_cn]

Dear all,

I encountered a very strange problem.
I used a crystal for a on-chip DCXO, but sometimes the oscillator did not start up after power-on.
At this time, I need to use my fingers to touch the crystal output cap. on the PCB to make the DCXO start to ocsillate.
I totally have no ideal about it.
Could you give me some help on this problem?
Thanks in advance!

Best,
Ken

 

[biff44]

you are adding some phase shift with your fingers. What this means is that the capacitors in the oscillator circuit are not the right value for startup AND sustained oscillation, and have to be changed.

 

[kiranvarma3]

I think your clock and capacitors are properly grounded. grounding to your circuit is done via your fingers. make sure that you solder the capacitors and clock properly. i too experienced the same problem so many times.