17th harmonic cr95HF

[JohnD1100]

I laid out a 2 layer board.  It works fine but fails radiated emissions by 3 dB.  Would a 4 layer board likely reduce this enough?

[JohnD1100]

I used a reference design and am afraid to start tweaking component values since it otherwise works well

[Richard Li]

For radiated emissions, first need fig out where is the leak, normally use rubber probe connect to spectrum analyzer ( ask FR test Lab, they can share equipment to you), test every trace.

Only increase PCB layer may not enough for this issue.

 

[Brian TIDAL]

Hi,

The ST25R95/CR95HF product is Not Recommended for New Designs (NRND). It is recommended to start new designs with ACTIVE products such as ST25R100, ST25R200, or ST25R210.

The X-NUCLEO-NFC03A1 evaluation board, which is based on ST25R95/CR95HF, uses a 2-layer PCB. Later versions in the ST25 NFC expansion lineup, such as X-NUCLEO-NFC05A1/06A1/08A1/etc., use a 4-layer design to accommodate separate ground and power planes. Critical traces can be embedded in inner layers and are therefore shielded further from radiated signals.

Rgds

BT