Hi Support Team
Is the oversampling mode the highest accuracy mode for the SAADC of nRF54L15? The datasheet mentioned a formula to calculate the improved SNR. What is the base SNR for the oversampling mode? Is the Oversample 256x in the oversample register the best accuracy for SAADC? is the (base SNR + 10log(256)) the best SNR? Many thanks.
Hi,
According to the official documentation, noise shaping modes offer highest performance. In these modes oversampling technique is also deployed. 
SAADC — Successive approximation analog-to-digital converter
dB SNR.
* In electrical specification you can see that the effective number of bits for 2 Msps with HFXO clock source is 9 bits which equal to around 56 dB SNR. So I would say you can assume that as base line for SNR under that specific condition. 
* Please note that if the analog input signal to ADC has lower SNR , for example 20 dB, then there is not much point of using oversampling as the signal itself is already within base line SNR of ADC (for that specific clock and condition).
* Also please note that when using over sampling, the effective signal bandwidth also will reduce proportionally. So it means by higher oversampling rate, the signal bandwidth should be lower.
Best regards,
Ressa
Hi,
According to the official documentation, noise shaping modes offer highest performance. In these modes oversampling technique is also deployed.
SAADC — Successive approximation analog-to-digital converter
dB SNR.
* In electrical specification you can see that the effective number of bits for 2 Msps with HFXO clock source is 9 bits which equal to around 56 dB SNR. So I would say you can assume that as base line for SNR under that specific condition.
* Please note that if the analog input signal to ADC has lower SNR , for example 20 dB, then there is not much point of using oversampling as the signal itself is already within base line SNR of ADC (for that specific clock and condition).
* Also please note that when using over sampling, the effective signal bandwidth also will reduce proportionally. So it means by higher oversampling rate, the signal bandwidth should be lower.
Best regards,
Ressa
