RE: nRF21540 questions

Bendik Heiskel — Mon, 07 Feb 2022 15:23:59 GMT

Hi,

[quote user=""]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?[/quote]

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.

[quote user=""]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?[/quote]

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.

[quote user=""]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?[/quote]

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

Best regards,

Bendik