XTR305: The Error flag signal error

Hi Zhang,

I'll take a look into this and get back to you as soon as I can. 

May I ask where these interference signals are coming from? 

Best Regards,

Robert Clifton

Hi Robert,

Robert Clifton56 said:

May I ask where these interference signals are coming from? 

We need to pass the RSCS testing and there are about 1GHz Wireless Signal for this testing, and we use the 433MHz interphone to close the board

to Simulate this testing, and the PIN18 and PIN19 will be automatic recovery if we remove this interference source,

1. We testing the power supplier +/16V is normal if the interphone closed to the board;

2. Our surge test is normal;

Plesae kindly advise if the XTR305 has the weak of radiation protection function? thanks.

Hi Zhang,

Thank you for the additional information. 

Have you verified that the interference isn't coming from the 3.3V supplies? 

Has this interference propagated to the OD pin? Has it caused to shutdown? 

Also the EF_CM and EF_LD should not be tied together. I'd recommend lowering the pull up resistor values of all of the error flag pins. I don't believe that should be the cause of the problems you are seeing but it's a serious concern. 

Best Regards,

Robert Clifton

Hi,

Robert Clifton56 said:

Has this interference propagated to the OD pin? Has it caused to shutdown? 

The product don't shutdown when we close up the RF interference source, it is only alarm from the MCU(The fault is LED flashing),

Robert Clifton56 said:

Also the EF_CM and EF_LD should not be tied together. I'd recommend lowering the pull up resistor values of all of the error flag pins. I'm don't believe that should be the cause of the problems you are seeing but it's a serious concern. 

We will test based on your suggestion, and will feedback to you soon.

BTW, we consider it is the radiation impact so can you help to check if there are any report for the radiation testing?

or are there any other customer feedback this issue to TI? thanks.

Hi Zhang,

Zhang Liang said:

BTW, we consider it is the radiation impact so can you help to check if there are any report for the radiation testing?

or are there any other customer feedback this issue to TI? thanks.

I've searched for any documents for under this and can't find any. Nor have I seen any customer having the issue in the past. I'll check with another colleague of mine to see if they have seen anything in the past. 

Best Regards,

Robert Clifton 

Hi Robert,

We modify our design based on your comment, but the issue is still exists, so pleaes kindly help how to solve this, thanks.

Hi Zhang,

I'm still waiting to hear back from my coworker but I'll re-ping him on this. 

Best Regards,

Robert Clifton 

Hi Zhang,

Would you be able to send me the layout of this board? 

Best Regards,

Robert Clifton 

Hi Robert,

Plesae review the attach, thanks.

SAQS-04SC 12_20250225.brd

Hi Zhang,

Zhang Liang said:

We modify our design based on your comment, but the issue is still exists, so pleaes kindly help how to solve this, thanks.

Did you separate the EF_CM and EF_LD pins? Did you also lower the resistance of all of the EF pull up resistors? 

Zhang Liang said:

BTW, we consider it is the radiation impact so can you help to check if there are any report for the radiation testing?

I was able to find that we did have some EMC testing done for reference designs for the XTR300 and XTR305. See here: https://www.ti.com/lit/ug/tidu434/tidu434.pdf and https://www.ti.com/lit/ug/tidue87/tidue87.pdf. The documents refer to IEC61000-4 and IEC61800-3 mostly. However it's focusing in on the output signals rather than the error flags. 

Perhaps it's time to take a step back from this and look at the error flags on their own. Let's assume that the fault conditions that are occurring on the EF pins are from actual fault conditions. Have you confirmed that none of the other pins experience any change during this RSCS testing? 

Best Regards,

Robert Clifton