SAR vs. Sigma-Delta ADC -- What is the difference anyway?

RE: SAR vs. Sigma-Delta ADC -- What is the difference anyway?

gervasi — Mon, 14 Dec 2020 17:16:55 GMT

I have used SAR and Sigma-Delta on many projects. This review helped jog my memory.

RE: SAR vs. Sigma-Delta ADC -- What is the difference anyway?

jc2048 — Thu, 07 Nov 2019 11:14:51 GMT

I'm sure you're right about SARs and sigma-delta being the most popular, given that most microcontrollers have a SAR ADC and that so much personal music equipment relies on the sigma-delta method, but it might be worth adding in a mention of dual-slope techniques - there are a fair number of digital multimeters in the world, even if it's a smaller market by volume.

In the flash section, what you call a 'decoder' I'd call an encoder (a priority encoder). I'd disagree slightly about the 'it is difficult to achieve more than 8-bit resolution'. When I started, even a six bit flash converter was amazing [and expensive], but later 10-bit and 12-bit were routinely being used for digital processing of analogue TV signals, 10-bit in consumer chips and 12-bit in studio equipment.

Other than those minor quibbles, a useful introduction to the topic.

As to your question at the end, I've used flash converters for processing video signals to drive LED screens (long time back), and SARs (in microcontrollers) for all the usual type of uses (reading sensors and pots, and monitoring voltage and current levels). I've never worked with sigma-delta converters.

RE: SAR vs. Sigma-Delta ADC -- What is the difference anyway?

geller12 — Thu, 07 Nov 2019 06:53:56 GMT

Thanks for this very nice and succinct introduction. It definitely helped me understand better the differences between some of these products and data acquisition devices I've used in the past.

RE: SAR vs. Sigma-Delta ADC -- What is the difference anyway?

clem57 — Thu, 10 Oct 2019 12:48:04 GMT

Real ADCs are not quite that coarse, of course

LOL

RE: SAR vs. Sigma-Delta ADC -- What is the difference anyway?

michaelkellett — Thu, 10 Oct 2019 08:56:24 GMT

A bit more homework would help:

From Analog Devices website:

Max resolution SAR converter: LTC2368-24, 24 bit

What about anti-alias filtering - the reason why nearly all audio ADCs are sigma-delta ?