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DM3725CPBA Assembly question

Jeffrey Lewis1
Prodigy 10 points

Other Parts Discussed in Thread: DM3725

We are having problems finding assembly houses that can competently assemble your DM3725CPBA cpu and memory onto a PCB. What are the technical assembly specifications, temperature ramp times and suggested assembly / integration procedures for this component?

Should  the assembly / integration be a 2 step process?  Should the cpu / memory be integrated separately before main PCB reflow?

Should the memory component then be staked to the DM3725 processor using a 2 step integration process using 2216 before main board assembly to prevent problems during main board reflow?

As It does not appear to be possible to discuss the difficulties with a human being, should we re-design with another vendor's component ?

Do you have a list of approved vendors that can assemble this configuration with 100% reliability?

Do you have a telephone number where I can discuss this issue with a REAL human being in REAL TIME?

IS there anybody at TI who still knows how to use a telephone?

We miss the old days when semiconductor companies had REAL technical support and not artificial internet "forget" and ignore support............

As usual, we will allow you 30 days to respond, then design a  component using a competitor's part

Please advise.

  • 0
    TI__Guru 65405 points

    Hi Jeffrey,

    The process of assembly (integration) of the cpu and memory could be executed as 2 step process but could be and 1 step process. The choice of method strongly depends on the manufacture equipment and number of board. Each of both methods has its advantages and disadvantages. 

    Memory attachment to the top of the processor is often considered one of the critical and most troublesome tasks in PoP assembly. Fortunately, this is not true. In fact, memory mounting has proven to be the least troublesome task.
    The primary concern is creating a strong solder joint between the memory ball and the processor pad. Simple screening of paste cannot be used, because the die is in the way. Two processes, paste deposition and flux dipping, have been developed and used in volume production. For very high-volume production, flux dipping is preferred because of its simplicity and speed.
    For the relatively low-volume BeagleBoard, a brushed-on tacky paste flux from Amtech, called LF4300 Tacky Solder Flux, was used. This material has the consistency of a gel and is simply brushed onto the OMAP3 memory pads. The BeagleBoard OMAP3 to memory attachment yield was excellent.
    For high-volume automated assembly, flux and a third option, solder paste dipping for the memory device, were evaluated.

    You can obtain more detailed description from the linked document:

    http://www.ti.com/lit/an/swpa156/swpa156.pdf

    There is telephone and email support provided by Customer support centers where you can discuss the issues.

    http://www.ti.com/general/docs/contact.tsp

    BR

    Tsvetolin Shulev