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TPS704: TPS70445 layer fault

Jun Ge
Prodigy 10 points
Part Number: TPS704

Hi ~

We ordered 4200pcs TPS70445PWP from TI eStore and it was shipped from TI SPG and USA twice time , But we found some quality issue by our quality department guys. 

Firstly, we followed recommended condition of TPS70445PWP to test, and use typical application circuit  of Darasheet to do the testing  each of 120pcs samples which D/C 2046+5 & 2041+5. Please also check photo of layered fault.

1, 18pcs   layered fault  while sound scanning. Environment tempature and humidity were normal as 25.6℃ and 53.6%.Fault rate was exceed 15%. 

2, 8pcs was found  layered fault,which fault rate was exceed 6.7%. same environment as above.

Secondly, all parameters of testing circuit were selected  as TI's recommendation, 5v input voltage was in the range of 2.7~6v, output was set fixed out as 3.3v@40mA and 1.2v@40mA with load resistor. then 2pcs aging failure was found after 48 hours aging test when we selected 100pcs testing devices.  failure rate is 2%. 

3, So we have stopped SMT operatoin already until   some  new devices was bought from other supplier,  Their device testing was  NONE of  fault . 

4, please refer to related layered fault photos and testing circuit as attached documents. 

    

 Kindly help refer check it,please. 

Best Regards!

Trigger Technology Co.Ltd 

  • 0
    TI__Genius 12040 points

    Hello,

              Could you provide us some clarifications on points listed below:

    (a) Were the 18 units (with fault rate > 18%) showing a different fault condition to that of the 8 units (with fault rate > 6.7%)? 

    (b) What fault condition did the two units that failed the ageing test show? 

    (c) Is my understanding correct that you purchased new TPS704 units from another supplier, and when tested on the same circuit there were no failures?

    (d) Could you provide us a schematic of the test circuit?

    Thanks!

    Regards,

    Srikanth

  • 0
    Prodigy 10 points

    Hi~ Thanks! 

        (a) it's the same conditioin to scan and test 18pcs and 8pcs fault devices. Same 5v input,  normal temperature (24.9~25.8℃) and humidity ( about 54%). 

        (b) After aging testing, only 0.55v output  in 1.2v fixed output pin. Almost no output voltage. 

        (c)Yes, we customized a specified testing circuit to check new coming material before inventory acceptance or SMT processing. 

        (d) Please check our schematic file of TPS70445PWP. 

        (e) BTW, TOTAL 4200pcs cargo's included many different tub's package as  35pcs, 1080pcs,1140pcs and 975pcs from SPG and U.S.A. 

    Best Regards!

  • 0 in reply to Jun Ge
    TI__Genius 12040 points

    Hello Jun,

                   The schematic and the component values selected look correct to me. I understand that you have a specified testing circuit, but could you confirm that there were no failures (including ageing test) observed on the new TPS704 units purchased from another supplier and that some of the parts purchased from the TI e-store failed on the same test circuit? Thanks!

    Regards,

    Srikanth  

  • 0 in reply to Srikanth Lolla Venkata
    Prodigy 10 points

    hI , Srikanth  , Thank you very mcuh for your kindly uggestion!!  

           We r selected about 100pcs tested samples from TI e-store and other supplier channel. No failures in other channel's device but few in TI estore's chips was tested in the same circuit . I confused that the result in standard basic circuit refer to TI' datasheet . Anyway,  I'll continue to use TI's ALL solution What ever happen. 

    Thanks and best Regards!

    Jun 

  • 0 in reply to Jun Ge
    TI__Genius 12040 points

    Hello Jun,

                    I do not believe that there is any systematic issue with your test setup. Could you provide us scope shots of Vin, Vout and Iout? This is just to make sure that the Abs Max ratings are not being violated during startup or transients. Thanks!

    Regards,

    Srikanth