NRF52832 QFAA without ANT

[Artem Efremov]

Hello guys,

I am currently looking at the recommended schematic QFN48 with internal LDO setup and I have a few questions (sorry, if they are silly, I am a newbie).

1. If my application does not use ANT (it uses only BLE), do I still need to connect High frequency chip inductor (L1) and capacitor (C3) to ports 30-31? Do I need to make any other changes in this case?
2. I can see that there are 3 ports for VDD (13, 36, 38). Do I need to supply voltage to all of them?
3. I use external LDO which outputs 3.3V. Do I still need to use internal LDO or DC/DC?

Thank you, Artem

[Jay Tyzzer]

Hello,

By the numbers..

1. Yes you must use these components. These components are used for impedance matching and also operate as a low pass filter.
   1a) Please review the layout in the Datasheet and be sure to follow the connection of C3 to Ground (pin 31 only) exactly!

2. Yes, you must supply voltage to those these pins.

3. The internal LDO will still operate when you supply power to the VDD_nRF Pins. The internal LDO regulates the Internal power to the different component blocks inside the device.

I hope this helped.

Jay T.

ADDED: You WILL need an antenna. They type you use is up to you. It can be anything from a piece of paperclip, to a PCBA trace, Chip antenna, etc. You should also add a PI antenna matching network after the 50 ohm feed point. This will be located near the antenna. This will allow the antenna to be tuned. During testing / tuning it will be determined how many of these components are used and what the optimal values are. Usually not all 3 components are used. Note in the attached picture that the shuts are left NP and the series should be populated with a Zero Ohm Resistor.. Nordic can help with your tuning as well. To do this you will need to create a Support case in the Nordic support portal and submit your design files. Nordic Technical Support will review and get back to you with any suggestions. Then you may send in your finished prototypes to Nordic for final tuning.

I hope this helped.. -- Jay

Pi network - good-2.jpg

[Artem Efremov]

Jay, thank you for your clear and concise answer! One additional question regarding the first point: do I need to use RF antenna?

[bjorn-spockeli]

Could you elaborate? If you're going to use the nRF52832 as BLE device then you will need a RF antenna.