RE: nrf54L15 PCB Design Review for IoT Device

Bendik Heiskel — Mon, 30 Mar 2026 11:49:50 GMT

Hi,

The nRF54L15-QFAA will not pass regulatory certification on a 2 layer board, it is sensitive to the distance to the GND layer under the ANT pin. If this distance is more than 100um the board will radiate harmonics above the FCC limits.
If you are planning on getting this board certified, you'll need to switch to a 4 layer board.
Another complication with just 2 layers is the routing of the DECA/DECRF connection, if it's routed directly under the XC1 and XC2 lines it can introduce noise to the clock signal which can impact the radio performance. On a 4 layer a internal GND layer would shield the traces, but on a 2 layer board the DECA/DECRF trace must be routed differently. The best option is probably to route it like this:
The antenna tuning capacitor C15 seems to be missing from the layout:
The filter components(C11 and R1) on the reset line must be moved as close as possible to the pin. These are required for filtering RF signal coupled from the ANT pin to the reset pin. If the filter is too far from the pin the reset trace will act as a antenna increasing the radiated RF noise.

Other than these points the schematic and layout looks OK.

Best regards,

Bendik

RE: nrf54L15 PCB Design Review for IoT Device

PjGlasso — Sat, 28 Mar 2026 08:33:12 GMT

Have you ever looked a a XIAO , its a nRF54L15 based MCU.
Seeed Studio makes them. maybe worth a look, easy to use on a PCB as well, Internal (ceramic) and EXT. ant is possible.

www.seeedstudio.com/Seeed-Studio-XIAO-c-2428.html

HTH

GL :-) PJ :v: