nRF9160 PCB land pattern

[JuhaK]

Hi,

As discussed, the instructed PCB land pattern for nRF9160 is according to Product Specification:

However, we have noticed that land pattern exceeds nRF9160 dimensions by ~0.5mm in DK (picture and gerber files):

91GerberFootprint.zip

Why extended land pattern is used in DK? Do you recommend this DK land pattern to be used in customer applications?

Br,

Juha

ps. I commented this already in December 2020 in some old thread but not sure if somebody reads it...

[Kaja]

Hi Juha,

use the footprint form the DK on your PCB the one in the PS is the mechanical specifications of the Zip. You can also use the mechanical drawing and extend the pad's. 

Best regards,
Kaja

[JuhaK]

Thanks Kaja!

What is the reason to extend the pads on the PCB, as our PCB space is quite limited? Futhermore, our surface mount assembly (SMA) specialists foresee issues due to different solder joint/mask areas for same size LGA pads (edge and inner pads) when paste may not spread in the same way on these two set sets of solder joints? Have you seen any issues related to this in your SMA?

Br,

JuhaK

[Kaja]

Hi Juha,

the point is to ensure proper connection and make it easier to route. No, it has not been an issue, you can have a look at our Hardware Design Guidelines 

Best regards,
Kaja

[JuhaK]

Hi Kaja,

Thank you for the reply! Do you mean by ensuring proper connection that solder joints would be unreliable or easy to break if the PCB pad size would equal the module pad size? Have you tried to use equal PCB pad size?

We don't see any issues in routing from equal size PCB pads. Anyway it's good that you haven't seen soldering issues in your proposed land pattern.

Hardware Design Guidelines link doesn't work for me. Instead I checked https://infocenter.nordicsemi.com/pdf/nwp_037.pdf but couldn't find comments related to PCB pad sizes.

Still, we have some area pressure to use smaller PCB pads in case there is no evidence on issues with them.

Br, JuhaK

[Kaja]

Hi Juha, 

more to ensure correct placement of the Zip. Check with your manufacture house, maybe they they have some input in regards to the distance between the pads.

Best regards,
Kaja