Author Topic: Via-in-pad on a flexible substrate?  (Read 566 times)

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Offline angust_ukTopic starter

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Via-in-pad on a flexible substrate?
« on: March 10, 2023, 12:57:46 pm »
Hi all

I am designing a flexible PCB which includes a 0.35mm pitch BGA device (https://www.ti.com/product/AFE4432). The manufacturer provides Gerbers for its evaluation board (image below) where they include vias in the pads, as otherwise clearance isn't sufficient to add traces between pads.

However I have checked with our usual PCB manufacturer and they do not support via-in-pad for flexible PCBs. Before I go and ask every PCB supplier I can Google, does anyone know if this is even possible? If not, are there any alternative options (other than not using this device)?

« Last Edit: March 10, 2023, 12:59:38 pm by angust_uk »
 

Offline AndyC_772

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Re: Via-in-pad on a flexible substrate?
« Reply #1 on: March 10, 2023, 01:50:15 pm »
Given the size of the solder joints, I wouldn't even consider putting a device like this on a flexible substrate. It's just asking for joints to crack and become intermittent.

If at all possible, I'd stick with components that can accommodate a small amount of bending, ie. SOICs, or passives that are constructed with soft terminations. Not BGAs, QFNs, or similar packages that have no capacity to deform.
 
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Offline angust_ukTopic starter

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Re: Via-in-pad on a flexible substrate?
« Reply #2 on: March 10, 2023, 02:08:19 pm »
Thanks for the reply. I wasn't sure about the reliability, but sounds like I need to rethink! In this case I maybe able to include a rigid section for this part, though I do still need to find a manufacturer who is able to do via-in-pad, if it is even possible!
 


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