Nokia / Flex _ subject: EP4CGX50DF27I7N FA request(ALCH-1AB269490003)

[JPeng7]

We captured some failed boards with the “Spare Parts final” failure step on 15235 model at FT.

• checked the related components no soldering issue and cosmetic issue no found.

• Take 3pcs failed boards to x-ray, no open or short issue found.

• Reheat the failed U18 BGAs, test still failed.

• Re-mounted the failed U18 BGAs ,test still failed.

• Remove the failed u18 and remount it in the passed board, the fail step and information is same.

Suspected the U18 BGA working abnormal. After replaced the suspect BGAs , the boards passed test process. So confirm that the fail symptom will follow the suspect BGAs.

[JPeng7]

1. Please provide full device details.

1.1.         Device Name:IC,FPGAxEP4CGX50DF27I7N SMCBGA

1.2.         Full Part Number[Jimmy Peng] : EP4CGX50DF27I7N

1.3.         Date code[Jimmy Peng] :2013

1.4.         Lot Number[Jimmy Peng] :3P9GE0G00

1.5.         Trace Code[Jimmy Peng] :S014AK59

1.6.        Distributor name:[Jimmy Peng] :Arrow

2. When did the failure happen? e.g before/after power up OR before/during/after configuration    OR in user mode?

            [RR: in user mode]

3. What is the failure rate? What is the failure rate vs. tested sample? Example: 2 out of 100 units.

            [RR:20 pcs out of 100 pcs] 

4.            What is the failure symptom? Please elaborate the failure symptom in detail.  

            [RR: Firstly: The failure occurs in FT station and test program indicates that no packet received from DUT. And the test principle of FT station is the signal goes into #1 optical, and via #2,3 and finally goes out from #4 optical port of DUT. So FT station only test the series loop signal. Also the LED are intermittent blinking which all LED light on means communication is ok or else miss the communication. Pls see below picture.

                      Secondly, all boards passed FCT station. But the FCT is bit different from FT station for this traffic test which this board contains 4 optical ports and the last 2 test items are traffic test which test principle is the signal goes into #1 optical port and goes out from #2 optical port. (#1 and #2 optical port connects with Smartbit test equipment #1 port). And the other signal goes into #3 optical port and goes out from #4 optical port(#3 and #4 optical port connects with Smartbit test equipment #2 port). So FCT station contains 2 groups signals test.]

5. When did the failure happen? How did you discover the failure?

             [RR: It happened in final test station (FT station). The test program shows the error that no packet received from DUT]

6. Did you swap the failure device to a known good board? Is the failure following the device or board?

                [RR: Yes , I swapped. And the failure followed the chip but not the board.]

7. Does the failure unit ever working before failure?

             [RR:YES, working]

8. May I know if this request comes from your side or end customer side? If the request is from end customer, please provide email proof.

            [RR: It comes from my side to dig root cause.]

9. Is this a prototype build or volume/mass production?

            [RR: Already mass run production]

10. Kindly provide quantitative investigation result that could proof the failure is Altera device induced.

            [RR:  1. checked the related components no soldering issue and cosmetic issue no found.

   2.Take 3pcs failed boards to x-ray, no open or short issue found.

   3.Reheat the failed U18 BGAs, test still failed.

   4.Re-mounted the failed U18 BGAs ,test  still failed.

   5.Remove the failed u18 and remount it in the passed board, the fail step and information is same.

Suspected the U18 BGA working abnormal. After replaced the suspect BGAs , the boards passed test process. So confirm that the fail symptom will follow the suspect BGAs]

11. Please provide design verification that current design implementation is meeting Altera spec in device data sheet.

             [RR: NA. There is no spec for final test which just no packet received from DUT.]