How to make a 10bit SAR ADC achieve 12bit resolution?

[spacejedigundam]

I want to do a 10bit ADC, but after run I an FFT, the ENOB (effective number of bits) result will achieve 12 bits.

Is this possible? How can I do it?



thanks reading

 

[danadakk]

Averaging and other topics, attached.

https://www.analog.com/media/en/training-seminars/tutorials/MT-003.pdf

https://www.ti.com/lit/an/sbaa254/sbaa254.pdf?ts=1644416710658&ref_url=https%253A%252F%252Fduckduckgo.com%252F

Be aware of the caveat of averaging and S/N improvement, its maximally effective when signal is un correlated, improvements decline as more correlation exists in the signal. Most designs, embedded, system has lots of correlated noise due to clocks and coupling into signal path via reduced PSSR and
capacitive issues.

Regards, Dana.

 

[Aussie Susan]

Also be aware that however many bits you can realistically use depends on the stability and noise characteristics of the surrounding circuits.
10 bits means that you have to have a stability of 1 part in 1000 (approx) and 12 bits means 1 part in ~4000. My rule of thumb is that for most purposes you can discount the lowest couple of bits of an ADC, even more if you go beyond 10 bits.
The techniques that Dana mentions (and others out there as well) will help improve things BUT at the cost of sampling time.
I'm reminded of the old saying: "cheap, fast, good - chose 2".
Susan

 

[stenzer]

Hi,

have a look at this application note from silicon labs.

https://www.silabs.com/documents/public/application-notes/an118.pdf

BR

 

[frankrose]

I think the original question is how can ENOB be higher than resolution without averaging, oversampling or other resolution improvement methods?

The answer is it can't be I think, and maybe you simulated the ADC without thermal, flicker, other uncorrelated noise. In simulation without uncorrelated noise the ENOB can be higher than resolution, but I wouldn't believe it.

It is not clear how did you run FFT, in simulation or on an oscilloscope under measurement.

 

[sam_sundar]

I want to do a 10bit ADC, but after run I an FFT, the ENOB (effective number of bits) result will achieve 12 bits.

Is this possible? How can I do it?



thanks reading

Oversampling is one of the method to achieve higher resolution. ENOB is still a function of data rate, so 12bit at what data rate