Verification for schematic for custom Board

[Moghees]

Hi,

We are design custom Board using nRF52840 SOC.

1. We are operating it in Normal mode, using internal DCDC converter
2. We have used configuration 5 from reference design
3. From reference design we have removed NFC pins connection and USB connection because we do not need it in our design
4. We will be programing our custom board using nRF52840 DK
5. We have attach led using load switch at P0.15
6. We have attach buzzer using load switch at P0.16
7. We have attach button at P0.24
8. We have taken antenna schematic from nRF52840DK hardware files and remove external connector. Have we done it correctly?
9. Have we connected reset button correctly?

I am attaching the Schematic design for our board can you verify it if it is correct or we are missing something, If it is unclear in picture I can also attach schematic file

Thanks in advance

Regards,

Moghees Bin Zahid

[Martin Sivertsen]

Hi Moghees,

Thanks for the detailed information.

When not using USB you can ground VBUS as seen in circuit configuration no. 6:

We have taken antenna schematic from nRF52840DK hardware files and remove external connector. Have we done it correctly?

Yes, but whether or not you only need antenna matching component C23 depends on what type of antenna you are planning on using. If you are copying the antenna layout from the nRF52840 DK, then one antenna matching component will probably work fine, otherwise we'd recommend a pi-network of antenna matching components for greater versatility in tuning the antenna.

The reset button is connected correctly.

What's just as critical is the PCB layout, so feel free to share that when you have it done and we can take a look at it.
If you follow the reference layout exactly you shouldn't have any issues.

Best regards,

Martin S.

[Moghees]

Thanks for the reply Martin. Firstly I want to appreciate the documentation of Nordic.  

Martin Sivertsen said:

Yes, but whether or not you only need antenna matching component C23 depends on what type of antenna you are planning on using. If you are copying the antenna layout from the nRF52840 DK, then one antenna matching component will probably work fine, otherwise we'd recommend a pi-network of antenna matching components for greater versatility in tuning the antenna.

I will be using same Antenna used in nRF52840DK. I want to ask can I copy antenna for nRF52840DK PCB layout and placed it on my PCB layout? If yes then in place of connector that is connected for external antenna of DK I should just extend antenna layout?

I have few others questions:
1. Can I remove net names and wires that I am not using in our design?

2. It is first time I am designing PCB using nRF52840 SoC. Can you recommend me document that I can follow?

3. Can I use reference layout PCB layout and extend it for our PCB?


Regards,
Moghees Bin Zahid

[Moghees]

Thankyou

Regards,
Moghees Bin Zahid

[Moghees]

Hi Martin,

any update?

[Martin Sivertsen]

Hi Moghees,

Some comments:

• Add a via here
  
• I doesn't look like you've added the equivalent of C21, C22, FB1 and FB2
  

Other than that it looks ok.

Best regards,

Martin S.

[Moghees]

Hi Martin,
Thanks for the review

Moghees said:

I will add Ferrite Bead in the next version of the PCB design is it ok?

I would like to add Ferrite Bead in the next version of the PCB design is it ok?


Regards,
Moghees Bin Zahid

[Martin Sivertsen]

Hi Moghees,

The ferrite bead is added to suppress electromagnetic intereference, and the capacitors are added close to the USB connector to smooth out ripple and higher frequency components in the voltage supply. If you omit these components you might get unwanted noise introduced to your circuit, which can affect different elements on your board. You can try without if you want to, but you should know what consequences it might have.

Best regards,

Martin S.

[Moghees]

Can you have a quick look at the below image and tell me if I had connected the ferrite bead correctly

U7 and U4 are ferritebeads

[Moghees]

Hi Martin,
I have added the Ferrite Bead in design. Can you kindly review it?

0638.LL_v0.4.0.zip


Regards,
Moghees Bin Zahid

[Moghees]

I have also added ground vias around the GND pad of components U7, C19, and C21

[Martin Sivertsen]

Hi Moghees,

That looks good.

Best regards,

Martin S.

[Moghees]

Hi Martin,
Thank you for the review

I want to confirm one thing

Previously I was using the following 12pF capacitor but now the PCB manufacturing facility has it out of stock:
C0G ±1% 12pF 50V 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHS for details click here

I think in place of it I can use the following component:
C0G ±2% 12pF 50V 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHS for details click here

Can you confirm if I am correct?

Once again Thank you very much for the review
Regards,
Moghees Bin zahid