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ADS1278-HT: HKP PACKAGE SOLDER

Frank Sun
Intellectual 925 points
Part Number: ADS1278-HT

Greetings,

I have a question on power pad solder of HKP package .

Part no. ADS1278SHKP

you can find HKP dwg in page 51 of Datasheet.

The dimension between Power pad and PCB pad is nom 0.33mm,

But generally the thickness of stencil is about 0.12 to 0.15mm.

In reflow process, is the solder enough?

Can powerpad be connected to PCB pad?

I am worry on this.

Can you give me some suggestions or guideline?

Thank u.

Regards,

  • 0
    TI__Mastermind 46580 points

    Hello Yumiko,

    I need to do some research to see if we have specific recommendations for the stencil thickness and area requirements  for this package.

    However, in general, the stencil used is much thinner than the height between the board and the thermal pad under the package.  Looking at the PAP package for the ADS1278-HT, the height is about 0.25mm with stencil recommendations from 0.1mm to 0.175mm thick.

    Please refer to section 2.5 of this application note that discusses this in more detail:

     https://www.ti.com/lit/an/slma002h/slma002h.pdf

    Since the height for the HKP is 0.33mm nom, you may want to consider using a thicker stencil, as well as a larger stencil opening.

    I will provide an update to you before end of week.

    Thank you,

    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    Intellectual 925 points

    Hi Keith,

    Thank you for your response.

    Waiting your feedback.

    Regards,

  • 0 in reply to Frank Sun
    TI__Mastermind 46580 points

    Hello Yumiko,

    We have searched for additional solder/mounting/stencil guidance regarding the HKP package, but as of today, have not located any data.

    At this point, I am going to assume that we do not have any additional information.  If something does surface, I will reply to this post.

    Regards,
    Keith

  • 0 in reply to Keith Nicholas
    Intellectual 925 points

    Hi Keith,

    OK, thank u for your response.

    I will reply to this post once I have any questions then.

    Regards,

  • 0 in reply to Frank Sun
    Intellectual 925 points

    Hi Keith,

    One more question,

    Can I do not solder this powerpad to PCB GN?

    I meant that can I make this pad floating?

    The stencil in my company is 0.17mm thickness,

    I can not use more thicker stencil as consider other parts soldering in my design,

    If the solder paste’s thickness is less than 0.33 mm,

    I do not think I can solder this powerpad successfully.

    Can I confirm the solder method or recommended condition again?

    Or do you have any other info to solder this powerpad?

    Or can I make it floating?

    Thanks.

    Regards,

  • 0 in reply to Frank Sun
    TI__Mastermind 46580 points

    Hello Yumiko,

    The powerpad should be soldered to the board for mechanical strength.  In addition, it is needed for thermal cooling of the device, especially if you are operating at the higher speeds where power dissipation in the device can be close to 1W.

    Internally, the powerpad is not connected to the ground on the device, but if it is electrically floating, it will be a source of noise pickup to the device.

    Regards,
    Keith

  • 0 in reply to Keith Nicholas
    Intellectual 925 points

    Thank u so much, but we still hope if TI can provide official documents on recommended solder condition for this package.

    Thanks,

    Regards,

  • 0 in reply to Frank Sun
    TI__Mastermind 46580 points

    Hello Yumiko,

    Unfortunately, I have not been able to locate any additional documentation.

    The HFQ version (non-formed leads) is used on the H.E.A.T. EVM; the design documentation may provide some additional guidance.

    https://www.ti.com/tool/TIDA-00002

    Regards,
    Keith