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TPS50601A-SP: DLA vs. TI datasheets, conflicting packages

Part Number: TPS50601A-SP

Hello, I am planning to use 5962R1022102VSC (TPS50601A-SP) in a space application. I am confused about the package size.

  • The TI datasheet gives the HKH0020A package outline with the thermal pad outline included. There is a note saying that it falls within MIL-STD-1835 CDFP-F11A.
  • The DLA datasheet specifies the case outline to be CDFP3-F20 and does not provide any outline for the thermal pad.

These two packages are not equivalent. Which is correct?

If the DLA datasheet is correct, what is the recommended thermal pad dimensions?

Also, is there any flexibility on the diameter of the thermal vias? The TI datasheet recommends 0.2mm (~80 mils); what would be the effect of increasing the diameter to, say, 120mils?

Thank you,

Alex 

  • Hi Alex,

    Thanks for pointing out this discrepancy.  I believe the TI package drawing has an error in note 5 as this note refers to an 11 terminal device while it is actually 20 pins.  I have asked our package team to confirm and update with a correction. 

    The TI drawing dimensions should be true to the device.  The CAD files including footprint that we used on our EVM are available in the product folder at the link below 

    https://vendor.ultralibrarian.com/TI/embedded/?gpn=TPS50601A-SP&package=HKH&pin=20&sid=215946299&c=1

    Note:  this footprint is for reference only and may or may not meet your specific requirements need for trim/forming the device; for more details see https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/996302/faq-pcb-footprint-and-trim-form-profiles-of-ceramic-space-power-devices)

    Regarding the thermal vias, our footprint is created using TI's guidelines for  PCB manufacturability.  Certainly there is flexibility in the footprint as every customer might have unique requirements.  I would expect little impact on device performance, if any, by changing this thermal via size from 80mils to 120mils. 

    Thanks

    Christian

  • Hi Christian, thanks for the quick response. I am afraid I am still confused.

    • I agree with you that note 5 in the TI datasheet appears to be in error. To be precise, I understood the reference to "CDFP-F11A" to refer to MIL-STD-1835 package type designator CDFP3-F28 (a 28 terminal device) with dimensions reference letter F-11A. Indeed, the device is only 20 pins.
    • Are you saying that the DLA datasheet reference to CDFP3-F20 is incorrect and I should follow the dimensions laid out in the TI datasheet? I ask because there are significant dimensional differences between the two, a couple examples below:
      • Package length (max): 12.95mm (TI), 13.72mm (DLA)
      • Bottom width (min): 4.62mm (TI), 3.30mm (DLA)

    Thanks also for the note on the thermal vias.

    Alex

  • HI Alex,

    Yes, the drawing in the TI datasheet most accurately represents the actual device and should be used for guidance. Could you please let me know from what figures and page numbers of MIL STD 1835 you are getting the DLA dimensions for CDFP3-F20 that you mention?  I will inform our team of this discrepancy also once I can refer them to the exact locations.

    Thanks

    Christian 

  • I am looking at MIL-STD-1835D downloaded from everyspec.com; because the printed page numbers appear to be non-consecutive, I will refer to the pages by their index in the overall PDF.

    The dimensions of CDFP3-F20 are contained on pages 44 (inch) and 45 (mm), see the F-9 variation column. Configuration B (bottom-brazed leads) is applicable, diagramed on page 36. Lead dimensions are shared by all configurations, diagramed on page 39.

    CDFP3-F20 is mapped to F-9 with configuration B in the package case outline list on page 18.

  • Hi Alex,

    Our packaging team has reviewed and provided summary of pertinent tables and drawings in the attached file.  Although it is true that the STD1835 min/max dimensions for CDFP3-F20 do not match the TI device, both are still true.  The dimensions for the device are within the range defined by the STD1835.  This standard encompasses many devices so the most accurate drawing to use is the one provided in the device datasheet specific to that orderable part number.  Nevertheless, we will update the footnote in the datasheet to reflect -F20 outline instead of -F9.

    Thanks

    Christian