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nRF21540 questions

DBT

After reading through the nRF21540 datasheet, I have a few questions.

1. Is section 5.5 saying that even though the spec for VDD is 1.7-3.6V, VDD needs to be between 3.45-3.6V when programming the UICR registers?

2. The MODE pin has a 33k ohm inline resistor on the datasheet reference circuitry, but not in the Thingy:53 schematic.  Is the 33k ohm needed?

3. ANT2 only has a 49.9 ohm resistor on the datasheet reference circuitry for single antenna, but the Thingy:53 includes an additional 2 capacitors and 1 inductor.  Are the capacitors and inductor needed?

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  • +1

    Hi,

    1. Is section 5.5 saying that even though the spec for VDD is 1.7-3.6V, VDD needs to be between 3.45-3.6V when programming the UICR registers?

    Yes, when programming the UICR registers the VDD voltage must be in the range specified. But since the UICR is one time programmable, the programming could be done during production with a external supply that is withing the specified voltage range.

    2. The MODE pin has a 33k ohm inline resistor on the datasheet reference circuitry, but not in the Thingy:53 schematic.  Is the 33k ohm needed?

    The 33 kOhm series resistor in the reference design is still needed. On the Thingy:53 uses a 2.2 kOhm series resistor which is based on a earlier reference schematic.

    3. ANT2 only has a 49.9 ohm resistor on the datasheet reference circuitry for single antenna, but the Thingy:53 includes an additional 2 capacitors and 1 inductor.  Are the capacitors and inductor needed?

    The capacitors and inductors should not be needed for terminating the unused antenna pin.

     

    Best regards,

    Bendik

Reply
  • +1

    Hi,

    1. Is section 5.5 saying that even though the spec for VDD is 1.7-3.6V, VDD needs to be between 3.45-3.6V when programming the UICR registers?

    Yes, when programming the UICR registers the VDD voltage must be in the range specified. But since the UICR is one time programmable, the programming could be done during production with a external supply that is withing the specified voltage range.

    2. The MODE pin has a 33k ohm inline resistor on the datasheet reference circuitry, but not in the Thingy:53 schematic.  Is the 33k ohm needed?

    The 33 kOhm series resistor in the reference design is still needed. On the Thingy:53 uses a 2.2 kOhm series resistor which is based on a earlier reference schematic.

    3. ANT2 only has a 49.9 ohm resistor on the datasheet reference circuitry for single antenna, but the Thingy:53 includes an additional 2 capacitors and 1 inductor.  Are the capacitors and inductor needed?

    The capacitors and inductors should not be needed for terminating the unused antenna pin.

     

    Best regards,

    Bendik

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