nrf52832 WLCSP - Avoiding DC/DC via in pad

[JPMorganJeremy]

Hello everyone, just a quick question.

When routing on the nrf52832 WLCSP package, I noticed that the only inner pin "required" for use is the pin to enable DC/DC (Pin B6).

To avoid using Via in Pad for only one pin, I saw a user suggest shorting across B5(AIN7) and A5(AIN6) in This Post.

A Nordic engineer suggested this shouldn't be a problem, so long as pins B5 and A5 where disabled in Software.

Yet there was another post asking the same question, with another Nordic engineer suggesting against it, in This Post

So I'm just curious if I could get away with the design suggestion in the first post (shorting B5 and A5) if I keep them disabled?

[Marjeris Romero]

Hi,

In the second post the customer wanted to measure the max and min DCC voltage using the respective AIN pins, which is not recommended because of the 4MHz pulse delivered by the DCC pin.

If AIN6 and AIN7 are kept disable then Andreas' answer in the first post is still valid, but the most common solution I have seen for 2 layers boards with the WLCSP package is using the internal LDO instead, as you can see from our reference design for nRF52832 CIAA which can be downloaded from the nRF52832 product page.

Best regards,

Marjeris

[JPMorganJeremy]

Thank you, I believe I will try shorting the AIN pins.

Any extra current consumption of 5uA or above is simply unacceptable for this specific design.