Smps and nrf24l01

[davids]

Is anybody have any experience powering nrf24l01 with smps stepdown converter?..i have trouble using fr9702 as 3.3 volt supply for nrf..the problem is..nr24L01 cant received any radio data..but no problem with the transmiting functionality..but wen i change the supply with 78L33 for down convert 12v to 3.3v..everything is run normally..note that the powersupply is in the same board with the nrf24L01 modul..and the smps controller have the fix frequency at 1.4MHz Any comment is appreciated

[ketil]

Hi,

It is most likely that you power supply has too much noise. The radio, RX and TX, is dependent on a stable power supply with little noise. The 2nd harmonic of the SMPS is almost the same as the RX local oscillator at ~2.8MHz. This will affect the receiver performance if the noise level is too high at this frequency. You can fix or improve this with better filtering of your power supply. If this doesn't help, you must use another regulator with a different switching frequency.

Ketil

[davids]

Hi..thanks Ketil... You are probably right..i was think the same thing with you..but i dont know that the rx local oscillator have twice my smps frequecy....it would be very likely the harmonic problem....filtering my smps seems too costly..it would be better if i change the smps controller with different frequency... Btw.. where you got the information about the rx local frequecy at 2.4MHz? And Wich tools do you think i can observe this problem..(other than spectrum analyzers..It is too costly for me

[ketil]

You may find hardware resources, whitepapers and application notes on the Nordic Infocenter.

Please note that the nRF24L01 is not recommended for new designs: "This product is not recommended for new designs. Nordic recommends its drop-in compatible nRF24L01+ or for a System-on-Chip solution the Nordic nRF24LE1 or nRF24LU1+ for new designs." We highly recommend you switch to nRF24L01+ or one of the other alternatives.

Please see this application note for testing the nRF24L01+ RF Performance and details about RX local oscillator.

[davids]

Actually Im using Nrf24L01+ for my project

[ketil]

That is great to hear that you are using nRF24L01+. Please let us know if you solve the problem