AD5474 Question

Mark Kachadorian

We are using your component ADS5474IPFP on our assemblies. Our assembly supplier recently noticed some variability ( using X-ray) in the quantity of solder contact area underneath the the component thermal pad. The solder contact area is varying. We noted the variation is due to the height difference of the parts - The lead / package planarity difference can vary a bit causing a change in the gap for the solder paste. This results in the different solder pad/component contact area coverage.
My question "what is the minimum % contact area do you believe we need for this part"?
Would we be conducting a valid experiment by measuring the solder contact area for a given part Vs the part case temperature to determine the correct solder load ?? If so, what Maximum case temperature do you recommend for performance and longevity ?

Thank you very much in advance. You help is important to our product quality.

over 9 years ago

0 Richard Prentice over 9 years ago

TI__Mastermind 29220 points

Hi,

I will have to consult with our packaging group to get an answer for this. I will either let you know what I find out, or give an estimate of when I can give an answer if thermal analysis is required.

Regards,

Richard P.

0 Mark Kachadorian over 9 years ago in reply to Richard Prentice

Prodigy 20 points

Any news on my question ??

0 Richard Prentice over 9 years ago in reply to Mark Kachadorian

TI__Mastermind 29220 points

Hi,
I will check with our packaging group in the morning and provide a status or expected time frame.
Regards,Richard P.

0 Richard Prentice over 9 years ago in reply to Richard Prentice

TI__Mastermind 29220 points

Hi,

Solder coverage of the thermal pad is something that has been looked at previously. In general, there needs to be a lot of solder coverage missing before the thermal characteristics of the device change appreciably. The two endpoints are 100% coverage and 0%coverage. With 0% coverage the thermal characteristics of the package are the same as a package that does not have the exposed power pad. With 100% coverage the thermal characteristics are as reported in the data sheet. But as solder coverage drops below 100% the thermal performance changes very little until coverage begins to get below 30% or so. At 80% or even 60% the thermal performance is nearly unchanged.

Regards,

Richard P.

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AD5474 Question