Part Number: BQ24640
Customer has some PCB manufacturing requirements that are imposed by the application and PCB manufacturer.
For the BQ24640RVA the PCB manufacturer need to use a PAD width of 0.2mm (see picture below).1)Can a 0.2mm PAD width be used for this package? Can a reliable soldering and long term device operation be garanty with this width?
2) Do we plan to have more industrial friendly package for the BQ24640 device? Or to have other supercap charger device in other package in the future? Any timeline?
3) I have seen the below FAQs page for QFN:http://www.ti.com/support-quality/faqs/qfn-son-faqs.html
The "QFN/SON PCB Attachment -SLUA271A" app note does not seem to be listed there.Is this app note relevant for S-VQFN-N16 too? Or is there a document specific for S-VQFN-N16?
Thanks in advance,
Regarding 1, below is the feedback from our packaging team.
"When customer stated that they want to use 0.2mm pad. That means they want to layout their PCB pad using 0.2mm in width.
The nominal width of the component pad is 0.24mm. If the PCB pad width is 0.2mm, then the solder joint shape would not be optimized. It will affect the solder joint reliability, putting most of the stress to the interface between PCB pad and solder joint causing earlier than expected failure.
Not recommended. "
Regarding 2, could you please let us know who is the customer? What is the end equipment? What is the requirements for more "industry friendly"? This is actually our first time learned about this 0.2mm requirement. It would be really helpful if you can provide more info to help us understand this requirement.
Regarding 3, this is a general document. Please see the link below.
Application Engineer, Battery Charging Products
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In reply to Jing Zou:
In reply to user5186153:
Thanks for the detailed explanation. My understanding is that the 0.2mm requirement is due to the base copper thickness of 105um. Is this correct?
We cannot warrant the operation when it is out of the datasheet spec.
LM5085 seems to be a buck controller only. Currently, bq24640 is the only supercap charger in our portolio. We do not have an alternative solution at this moment.
I am not very familiar with LM5085. My only concern would be when the supercap is completed depleted, would LM5085 able to charge it up. You might want to start a separate post on LM5085 on this.
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