Effective resolution and dynamic range (of ADC)

[dirac16]

Do effective resolution and dynamic range describe the same thing? Per my understanding, the effective resolution and dynamic range are defined as the ratio of the full-scale input range to the RMS input noise, including both the intrinsic and quantization noise. The only difference I found was in the format they are represented in, which for the effective resolution it is usually bits and for the dynamic range it is dB. Am I right?

 

[frankrose]

ENOB is the effective resolution, ENOB=(SINAD-1.76dB)/6.02, where SINAD is the signal ratio to all noise and distortion, in decibel unit.
Dynamic range is 6.02*N, where N is the resolution, unit is decibel too. But it doesn't care with all noise and/or distortion.
Spurious free dynamic range is a different thing too.

 

[dirac16]

ENOB is the effective resolution, ENOB=(SINAD-1.76dB)/6.02, where SINAD is the signal ratio to all noise and distortion, in decibel unit.
Dynamic range is 6.02*N, where N is the resolution, unit is decibel too. But it doesn't care with all noise and/or distortion.
Spurious free dynamic range is a different thing too.

No I think ENOB and effective resolution are not the same thing. See https://www.analog.com/media/en/analog-dialogue/volume-40/number-1/articles/adc-input-noise.pdf

 

[frankrose]

Oh, I have learnt something today, thanks!
I have never used this before. Seems important only for sigma delta or high resolution ADC, which I have never designed. And actually I have opened ADC datasheets which are linked in descriptions from Analog, Maxim and TI, but they don't show exactly this parameter, rather noise free dynamic range and ENOB, it makes sense.
I hope this is not a marketing parameter only to advertise ADC with higher numbers.

 

[Warpspeed]

An ADC does not always need to be linear.
For some special applications that need to have an exceptionally wide dynamic range, the ADC may be preceeded by a log amplifier. That can simplify things a great deal as well as reducing the required number of bits.

 

[AMS012]

Effective resolution is usually given by the ENOB (given by (Max SNR - 1.76)/6.02). ADC's resolution is always mentioned with no. of bits. It has to be the ENOB.

Dynamic range is usually defined in ADCs as the range of input that it can resolve meaningfully. In other words, as you keep reducing the input signal, at some point the SNR goes to zero, with the noise being quantization/thermal noise. Also, as you keep increasing the input signal, at some point, the SNR goes to zero, with the noise power dominated by the harmonic distortion. The difference between the two input levels is the dynamic range usually given in dB. In all the above, the term SNR includes all kinds of noise and distortion. Dynamic range is usually used in communication application, where it is important to know what is the highest and lowest signal your receiver (having the ADC at the backend) can detect.

SFDR in ADCs is defined as the difference between the input signal and the highest non-harmonic spurious tone strength, usually given in dB. This has to be non-harmonic spur, because HD2/HD3 are anyway separately quoted, and you want to characterize the other non-linearities (like the effects of DNL/INL, idle tones, tonal nature of the comparator etc.) of the ADC through what is called SFDR.