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BQ 25570 Initial contacting test

Volker Skwarek
Prodigy 60 points
Other Parts Discussed in Thread: BQ25570

Is there an internal testing procedure for checking the proper PCB-connection of the chip without setting up all the rest of the resistors and capacitors? For QFN-housing with pads only below the chip it is for my understanding essential to check contacts.

By the way:  May there be a mistake in the documentation: It says in chapter 7.3.2: "For the VBAT_UV feature to function properly, the system load should be connected to the VSTOR pin while the storage element should be connected to the VBAT pin." But shouldn't the system load be connected to V_out? Even in all your application examples, you never connected the system load to vstor. Actually, I am not really sure, what the externally accessible pin vstor should be good for.

Regards,

Volker

  • 0
    TI__Expert 6640 points
    Dear team,

    could you please help this customer?

    Thanks a lot in advance for your support.


    Best regards,

    Massimiliano De Cristofaro
    Application Support Engineer - Power Management
    ASKTEXAS DiamondLane – EMEA Distribution Support
    Texas Instruments Deutschland
  • 0 in reply to Massimiliano De Cristofaro
    TI__Genius 12485 points

    Volker,

    You could probably check for continuity test or do an image test post reflow.

    That looks like a copy/paste error. thanks for catching that! the system load will be connected to VOUT on the BQ25570.

    thanks,

    Gautham

  • 0 in reply to Gautham
    Prodigy 60 points

    Thanks Gautham.

    What do you mean with a continuity test or an image test - do you mean x-ray?

    During initial prototyping X-ray is a really high effort. You probably have a post-production inline test for the components, where you check some basic functionalities or perhaps even only the contacting of the bond wires.

    I would expect something similar. You should understand, the IC is very complex to apply and principally only works as a system. If you (or better: I) make first attempts to get this chip known, I need to assemble it including all environmental components - and then it is a 0/1-game: either the system works - or not... 

    Unfortunately it is nearly impossible first to start with setting up this, continuing with that, .... and always testing it inbetween.

    Therefore I would expect some very easy fundamental tests - perhaps some reverse voltage tests, using internal protection diodes - just for understanding if a single part of a layout at lest "formally" works.

    For an international research project, preparing a a series production of a measurement platform, I have now set up 10 prototypes  with about only 5 of them really working and all 5 showing different behaviour although there is a identical setup. (But I will open an additional case for that...)

    So: Is there a basic, stepwise setup-and-testing routine?

    Regards,

    Volker

  • 0 in reply to Volker Skwarek
    TI__Genius 12485 points
    Volker,

    That's exactly what the continuity test is "using the internal protection diodes"

    This document is a good link which i have read in the past. --> www.ni.com/.../

    Also from your description i would also recommend a functional test which would involve reading the votlages on VIN, VOUT, VSTOR and VBAT.

    (note that with a fully wired circuit, continuity test might be harder due to passives connected on the pins)

    reagrds,
    gautham