nRF52811 shows up, but cant connect bluetooth.

RE: nRF52811 shows up, but cant connect bluetooth.

Kazi Afroza Sultana — Mon, 02 May 2022 10:29:09 GMT

Hello Mathias,

Thanks for your design.

I have looked at the design.

Antenna in the middle is not a recommended design and there is not enough ground plane in entire design (no ground plane on top). A matching network is needed between the RF pin and the antenna impedance normally 50 ohm) to the optimum RF load impedance for the chip. In addition to this , the two vias near antenna are quite big.

You can look at our reference design https://infocenter.nordicsemi.com/topic/ps_nrf52811/ref_circuitry.html?cp=4_4_0_6_2_2#unique_140383198 and we have white paper that describes antenna tuning https://infocenter.nordicsemi.com/pdf/nwp_017.pdf?cp=17_15 .

Looking at these issues perhaps you need to redesign to get the Bluetooth connection.

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: nRF52811 shows up, but cant connect bluetooth.

Mathias Lundberg — Sat, 30 Apr 2022 10:18:03 GMT

Hello Kazi,

Im using the reffrence design from the documentation for the nrf52811 QFN32 using the internal LDO setup. Im not using the optional crystal. (I dont know if have have to specify this in the config somewhere). Here are the PCB design top and bottom im using. You can see the inverted F antenna in the middle. The 2 biggest VIAS is where i connect my power supply. Im fairly new to SoCs and antennas so please keep that in mind.

The name of the components is the same as they are in the reffrence design. The IR is an LED im working on.

RE: nRF52811 shows up, but cant connect bluetooth.

Kazi Afroza Sultana — Fri, 29 Apr 2022 14:12:33 GMT

Hello Mathias,

We would like to see the design of your board. Could you please send both of the schematic and pcb design?

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: nRF52811 shows up, but cant connect bluetooth.

Fredrik Sannerhaugen — Fri, 29 Apr 2022 12:04:50 GMT

I have the same exact issue