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QFN-32 5x5 breakout (product 1163)
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QFN-32 5x5 breakout (product 1163)

by thrusty on Sat Aug 27, 2016 9:01 am

Hi, I just soldered an STM32F051xx to the QFN-32 5x5 breakout. This chip is the "UFQFPN32" package.

Imagine my surprise when I went to connect Vss / GND and found that the breakout has no connection to the center exposed pad. Any suggestions on how to connect to this? My best idea right now is to drill through the center of the breakout before soldering the chip.

For the next revision of this product it would be helpful if the center exposed pad were routed to a breakout pin.

thrusty
 
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Re: QFN-32 5x5 breakout (product 1163)

by adafruit2 on Mon Aug 29, 2016 4:38 pm

the only way to connect to GND is from the center pad? thats...very unusual. normally there's other GND pins and the center pad is mechanical

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Re: QFN-32 5x5 breakout (product 1163)

by thrusty on Mon Aug 29, 2016 11:35 pm

image.jpeg
Stm32f051 pinout
image.jpeg (109.94 KiB) Viewed 111 times

Yeah, not sure how common that is for this package, but ST does it.

Proto Advantage supplies two different Qfn-32 breakouts, one of which routes the center pad to a dip pin:

http://www.proto-advantage.com/store/pr ... id=3100020

thrusty
 
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Re: QFN-32 5x5 breakout (product 1163)

by adafruit2 on Mon Aug 29, 2016 11:45 pm

wow thats horrible of ST - a first! :) ok will see about next run doing a redesign

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Please be positive and constructive with your questions and comments.