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6/1/16: SAR vs Sigma-Delta

When designing for low noise, is a precision SAR converter better or a Sigma-Delta?

[edited by: lallison at 3:54 PM (GMT -4) on 6 Jun 2022]
  • It depends what you're trying to do. Precision Sigma-Delta converters are often a great choice for dc circuits for several reasons, they usually have noise shaping, which allows you to get better noise at low frequencies, they often have sinc filters or other filters built-in, and with something like a sinc filter you may be able to set the update rate to reject 50 and 60Hz power line noise. From my perspective, the main benefit of a precision SAR is the flexibility. You can scale the power by scaling the sampling frequency, you can do any digital processing that you need to, you can have multiplexed circuits in front of them to scan channels with low latency. Whatever converter you choose, just make sure it is a sensible choice given the design constraints of your system.