02-09-2021, 04:04 PM
Historically, the first and most important decision regarding Analog-to-Digital conversion was which topology to chose for your project. Anymore, unless you have a special case, the decision is easy. The Delta-Sigma (or Sigma-Delta, if you prefer) converter has swept the competition away for most applications.
It might seem normal that new technology would replace old, but the more usual case involves incremental improvements. Delta-Sigma is not only a radical departure, but also a dramatic improvement. The tradeoffs between speed and susceptibility to noise used to be the nub of the A/D debate. Delta-Sigma can be both faster, and quieter. Faster A/D converters tend to require higher power. More power means more self-heating, which leads to more temperature drift. Since even fast Delta Sigma converters tend towards low power, they win on that score, as well.
When you look back on a project and rate it compared to others, the tendency is to grade alternate techniques by ease of use. Delta-Sigma shines there, too. The noise rejection makes your signal conditioning look good, and the programmability allows you to optimize performance without redesigning the circuit board. Keeping a project on schedule helps with quality of life, and isn't bad for your career prospects, either.
The Types of A/D white paper has been updated. https://lawsonlabs.com/whitepapers/typesofAD.pdf
A quick review will provide perspective on how we got here, and just may enhance your appreciation for what Delta-Sigma converters have done to make the engineer's life easier.
Tom Lawson
February 2021
It might seem normal that new technology would replace old, but the more usual case involves incremental improvements. Delta-Sigma is not only a radical departure, but also a dramatic improvement. The tradeoffs between speed and susceptibility to noise used to be the nub of the A/D debate. Delta-Sigma can be both faster, and quieter. Faster A/D converters tend to require higher power. More power means more self-heating, which leads to more temperature drift. Since even fast Delta Sigma converters tend towards low power, they win on that score, as well.
When you look back on a project and rate it compared to others, the tendency is to grade alternate techniques by ease of use. Delta-Sigma shines there, too. The noise rejection makes your signal conditioning look good, and the programmability allows you to optimize performance without redesigning the circuit board. Keeping a project on schedule helps with quality of life, and isn't bad for your career prospects, either.
The Types of A/D white paper has been updated. https://lawsonlabs.com/whitepapers/typesofAD.pdf
A quick review will provide perspective on how we got here, and just may enhance your appreciation for what Delta-Sigma converters have done to make the engineer's life easier.
Tom Lawson
February 2021