htg
Full Member level 5
If I want e.g. 28-bit accurate A/D conversion by multiple conversions and averaging, what is the optimal A/D converter - so that total conversion time is the shortest?
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Averaging multiple conversions can reduce noise but not inherent ADC errors, particularly non-linearity. To achieve 28 bit accuracy, you need an ADC with 28 bit integral linearity. There are a few ADC in the 24 to 32 bit range available on the market, I presume all of the sigma/delta type. What's the intended sample rate?
If I want to know this ... I'd use selection guides and chart from manufacturers and distributors.What is the fastest 28-bit A/D converter?
Hi,
More bits doesn't mean better performance.
I've seen a lot of 24 bits ADCs that don't have better performance than 16 but ADCs.
And honestly I've not seen an ADC with true 24 bit performance.
My recommendation: forget about 28 bits.
The other point is, that even if you have an ADC with true 24 bit performance..you need to design the surrounding circuit to keep this performance.
I'm doing high precision electronics for decades now, but I don't think I'm able to design a true 24 bit performance system.
For a 3V range a 24bit resolution means about 180nV/LSB.
Thermocouple effects and even mechanical stress will make 24bits precision impossible.
If I want to know this ... I'd use selection guides and chart from manufacturers and distributors.
Klaus
I can't think of an application where 28 bit precision is needed ...New production techniques may be necessary - e.g. all Cu ICs including leads, microwelding. For a given A/D converter it is possible to compensate for nonlinearity.
You can answer the question in two regards.What is the fastest 28-bit A/D converter?
Major manufacturers (Analog, TI, Maxim etc.) are working hard for decades to push the limits. Be pretty sure that they already consider all available technologies.New production techniques may be necessary - e.g. all Cu ICs including leads, microwelding. For a given A/D converter it is possible to compensate for nonlinearity.
Hi,
More bits doesn't mean better performance.
I've seen a lot of 24 bits ADCs that don't have better performance than 16 but ADCs.
And honestly I've not seen an ADC with true 24 bit performance.
My recommendation: forget about 28 bits.
The other point is, that even if you have an ADC with true 24 bit performance..you need to design the surrounding circuit to keep this performance.
I'm doing high precision electronics for decades now, but I don't think I'm able to design a true 24 bit performance system.
For a 3V range a 24bit resolution means about 180nV/LSB.
Thermocouple effects and even mechanical stress will make 24bits precision impossible.
If I want to know this ... I'd use selection guides and chart from manufacturers and distributors.
Klaus