esim(MFF2) location related to nRF9160 for EMI

[soonisys]

Hello.

 

I have couple of questions for hardware parts location on pcb with nRF9160.

Q1.

I'd like to ask a better location for eSIM(MFF2) related nRF9150.

      This is my guess for each positions.

       Postion.A: The uicc traces are very short. But eSIM is very close to LTE ANT connector.

       Position.B: The eSIM is far from LTE ANT. But uicc traces are longer then Position.A.

                          GPS ANT close to eSIM is fine, since I'm not sure if I will use GPS or not.

Q2.

I see there is EMI filter for sim-holder but eSIM on DK/Thingy board.

I wonder why there is EMI filter only for sim-holder?

Q3.

Is it fine if I put the inductor for DC-DC converter very near by nRF9160? (for RF)

Thanks.

 

 

[Martin Sivertsen]

Hello,

Q1: Position A is best due to shorter routing path, but the eSIM shouldn't be close to the antenna. We have a hardware integration guide which includes some guidelines for component placement.
You could place the eSIM on the other side of the board and have the eSIM and nRF9160 separated by a ground layer.

Q2: The EMI filter is there primarily to dissipate ESD when inserting the SIM-card.

Q3: This is related to Q1, and it would perhaps be better to place the DC-DC converter on the bottom to increase isolation. I understand that you might not have much room on such a small PCB.

Best regards,

Martin S.

[soonisys]

Thanks you for your answer.

I can not place any part on bottom side, since my board will be mounted on another board.

Then. do you think pos.A is still better then pos.B?

[Martin Sivertsen]

Hi,

I still think pos. A is better, but you could move it back a bit:

Best regards,

Martin S.