Author Topic: Basic question on sigma-delta IC  (Read 1002 times)

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Offline zphazeTopic starter

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Basic question on sigma-delta IC
« on: January 26, 2020, 05:10:36 am »
Hi,

I'm considering two chips for current sensing.
#1 is this one: http://www.ti.com/lit/ds/symlink/ads131e08s.pdf
#2 is this one: https://www.analog.com/media/en/technical-documentation/data-sheets/AD7175-8.pdf

The TI one says "simultaneous sampling" at 64 ksps. The Analog one would be better for me because it can be made single ended with 16 channels. The thing is it has a MUX inside and I can't really (or I'm not looking at the right place) find any info on whether at 16 channels it can do 250ksps per channel.

So I wonder if anyone who has perhaps worked with those knows if the 250ksps can be achieved with 16 channels or should I expect something like 250ksps/16ch sampling rate per channel.

Thanks in advance!
 

Offline moffy

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Re: Basic question on sigma-delta IC
« Reply #1 on: January 26, 2020, 06:48:53 am »
The AD7175 only has 1 ADC for 16 channels, so max rate for 1 channel = 250ksps, max rate for 1 of 16 channels is = 250k/16 (assuming no delays involved in multiplexer switching. Unfortunately sigma-deltas normally incur a switching penalty because of the digital filter). The TI device has a dedicated ADC for each channel so you get the full 64k for each channel.
 


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