Is the nrf54L10 output spectrum stable above the recommended VDD?

[RFEE]

Hi,

Is there a way to implement overvoltage lockout by sensing VDD using the ADC? Our goal is to claim that we have power regulation so that we can get full modular certification under the FCC rule without the use of an external LDO.

If the RF output spectrum (fundamental ~ 5th harmonics) will not degrade until the chip blows up when the VDD hits ~3.9v, then I won't need to implement any power regulation externally or internally.

Thanks,

Albert

[Ressa]

Hi Albert,

Increased VDD voltage does not necessarily lead to higher harmonics emission on nRF54L10. Just wondering where did you get this impression from? 

Br,
Ressa

[RFEE]

Ressa,

Because that is the only concern the FCC has if we don't use an external regulator. 

[Ressa]

The supply voltage to PA of radio is regulated by chip itself. DECRF pin is the voltage supply to PA and radio, you can measure it over different supply voltages and you will see it is fixed as it is regulated by chip internally. 

Br,
Ressa

[RFEE]

So even up to the point of failure. We should expect the PA and the rest of the TX system to operate normally?

[Ressa]

Yes. Over entire recommended operating voltage range the TX will operate normally. 
I know there are SoCs out in market that have unregulated PA which means the power supply goes directly to the PA. But that is not the case for nRF54L series.