Short circiut on 52811

[Tron]

Hi 

On some devices we see in the production a shortcut between the BT antenna and the P0.18 pin on the 52811. The cause can be extremely warm weather at the production facility, and the soldering paste may be more fluid than normal. 

The P0.18 pin is not connected to anything, and the antenna is of course connected to the antenna circuitry. 

What harm may this do to the BT device?

Yours, 

Tron

[Simonr]

Hi Tron

The ANT pin will get a shunt stub with a capacitance (Cpin) ~3-4pF mismatch in the end, which is likely to affect the antenna/radio performance negatively. You might also see that the harmonics are affected, probably enough that the board does not pass the regulations.

It is highly recommended that shorting any pins with the ANT pin is avoided to ensure optimal antenna performance.

Best regards,

Simon

[Tron]

Thank you, this is not something done intentionally. It's a mishap on some of the units in the production.