nRF54L NRESET pin reference design termination

[jlegstrong]

Hi,

I noticed in the nRF54L QFN48 reference design, for the NRESET pin, there is an RC filter (1Kohm series R and 3.9pF shunt cap). What's this for and is it necessary? The CSP47 reference design does not show any passives on the same pin (why?).

Since there is an internal weak pullup, can we just leave it floating if unused or directly connect it to an external GPIO?

Thanks

[Priyanka]

Hi Tim,

I see that you were provided with an answer for the same in another ticket. These values were chosen due to coupling of the 2nd harmonic from the neighboring ANT pin to this pin.

If you have no further queries, is it okay to close the ticket?

Regards,

Priyanka

[jlegstrong]

Thanks Priyanka,

One followup- if the pin is not used, can we leave it completely NC or is some termination still recommended? I see there is an internal pullup on the NRESET pin so it looks like we can just leave the pin floating. In our design it is broken out to a floating test point (not sure if having that stub matters)