Footprint LPS27HHTW - connection of central GND pin

[bjoern_1]

Hi,

according figure 3 in the datasheet, the pin in the middle (let's name it pin 11) is connected to GND, but this pin is missing in table 1.
The linked technical note TN0018 advises to avoid any GND/copper/via below the IC (Figure 12).
The eval board STEVAL-MKI220V1 has a pad for pin 11 but the pad is left floating.
The SamacSys-symbol/footprint contains this as Pin 11 / GND_3

I see multiple contradictory solutions:

1. no pad for pin 11 in the footprint, pin 11 is left floating (complies with TN0018, but contradicts eval board, SamacSys-footprint and maybe the datasheet)
2. add a pad for pin 11 in the footprint, but leave the pad floating (violates TN0018, but complies with the eval board)
3. add a pad for pin 11 in the footprint, and connect the pin to GND (violates TN0018 and eval board, but seems to be suggested by the datasheet)

What is the correct solution?

Regards
Bjoern

[Federica Bossi]

Hi @bjoern_1 ,

You can include a pad for pin 11 in the footprint (for mechanical stability and alignment with the eval board) and leave pin 11 floating (not connected to GND).

Avoid placing copper or vias under the IC in the pin 11 area, following TN0018 recommendations.

This approach aligns with the official eval board, respects TN0018 guidelines, and avoids potential noise issues.