WL1831MOD: WL1831 temperature cycle test failture

Dear TI:
Sorry, the test is not really temperature cycle test, it is thermal shock test.

Hi Vihang:

      Thanks!

      Customer give me a information of WL1831 datasheet, the temperature  range is -40℃ to 85℃：

Hi Eric,

Are you using the WL1831MOD module? or a chip down design?

Best regards,
Vihang

Hi Vihang:
    Customer used WL1831GYFVR to design product, not used WL1831MOD.

Best regards.

Eric Shen

Hello Riz, 

Customer use our IC not module, so the operation temperature range is from -40~85. test 4 pcs, find 4 pcs failure. 

test condition is as below: 

1.Temperature cycle test, -30~80, the cycle time is 2H, The cycle is 3000;

2.the system without power

3.Before the test, test the function is normal

4.After 3000 cycle temperature test, stay the product in normal temperature about 25 2 hours, Power on, find function failure, UART can load the stack code. 

The failure statue is RTS pin is high always, so the UART can't work normal. 

Hi,

Is there a pull or pull down resistor on the line? If you remove this does it work? I want to understand if it is a failure of the IC or the supporting circuitry.

1) have you done XRAYs of the boards to ensure there are no solder voids under the IC? Other parts on the board?
2) is there sufficient grounding under the part that follows our design rules for the IC?

Thanks,
Riz

hello Riz, 

Before the test, the function is normal, after the test, do the same function test, failure. we have reviewed the sch and PCB layout. don't find any problem. 

another one, change a new WL1831, the PCBA is normal again. so we think the IC damage. 

we don't do X-RAY for the failure broad. 

Hi,

Yes I understand that there is a failure after temp cycle and it was normal to start. What I am wondering is how well the soldering is. IF it is "week" to start with, that is >30% voiding, then the temp cycling may cause the damage. Thus XRAYs are important to review and to review.

A few more questions.

1) How many boards does this happen on?
2) how many have you tested
3) when you replace the IC and retest the temp cycling do you pass?

Thanks,
Riz

hello Riz, 

still not close the issue, i have sent the mail to you, but don't get your feedback till now.

i have asked customer to do the test again, but the time is very long.