MSP430FR6047: LFXT oscillator fault during ESD testing

Hi Cash, 

We have tried to follow the guideline suggested by TI but there may be some problem. FYI,

1. There is no digital signal line on other side of PCB.

2. No digital signal traces near LFXT.

3. Traces connecting the crystal are short.

4. I have doubt in the guard ring, can you please check?

Thanks,

Piyush

Where is this ESD coming from? It seems odd that you are treating the LFXT instead of the signal lines bringing the ESD into the system.

Hi David,

As per our observation ESD in not conducting to our PCB, may be EM field is generating inside the Meter due to the charge accumulation.

I may be wrong here, I am telling as per our observation and knowledge.

FYI, meter PCB is enclosed in plastic body and the power source is battery which is also inside the same enclosure.

Regds

Piyush 

Hi Piyush,

Okay. If there is EM field is generating inside the meter. Is there any way to conduct the charge accumulation to an external ground plane? It should be helpful this way. 

Best regards,

Cash Hao

Hi Cash,

Here I am not sure how to do so, you may suggest here.

Do you see any ambiguity in guard ring around the crystal, actually we have shorted the ring to same ground plane.

Thanks & Regards

Piyush

Hi Piyush,

The guard ring looks okay to me. I mean that if you have a ground plane, you can try to connect the board ground to it. 

Best regards,

Cash Hao