Looking for Isolated ADC

Thread Starter

Matterh

Joined Nov 24, 2019
5
I am looking for an Isolated ADC, the googles struggles to find one. I found many isolated ADC for shunts but thats about it except SI8902.

SI8902 is perfect! Except it is only 10bit and I need a minimal of 12bit resolution.

GOD DAM IT !

Been searching for a while, SI8902 is so close! The fact that it has 3 channels is a bonus as well. 4 channels would of been perfect. And the channels are single ended, nice.

I love SI8902! It is perfect! Why is it only 10bit.... meh
 

pmd34

Joined Feb 22, 2014
499
You could consider using an ADC with serial communication and then using an opto-isolator to isolate the output signal.
Or you could consider using an "isolation amplifier" such as the AMC1200 that way you only need to isolate the analog signal itself.
 

Thread Starter

Matterh

Joined Nov 24, 2019
5
Why not use a normal ADC and a digital isolator like adum1401?
I have done that, but why spend money on two parts when you can spend money on one? ADC and DI are expensive and make a big difference if you have to have multiple on one board.
 

Thread Starter

Matterh

Joined Nov 24, 2019
5
You could consider using an ADC with serial communication and then using an opto-isolator to isolate the output signal.
Or you could consider using an "isolation amplifier" such as the AMC1200 that way you only need to isolate the analog signal itself.
I have seen AMC1200, but the voltage measurements will be more then 1v after a voltage divider and as high as 4v and you cant have too much of a voltage divider as this impacts accuracy.
 

Papabravo

Joined Feb 24, 2006
12,697
I'm not clear on where you need the isolation boundary to be, or what the possible solution set might allow. Could you possibly explain the problem rather than infer a solution.
 

pmd34

Joined Feb 22, 2014
499
I have seen AMC1200, but the voltage measurements will be more then 1v after a voltage divider and as high as 4v and you cant have too much of a voltage divider as this impacts accuracy.
You can always calibrate your actual voltage divider once it is built, or use an off the shelf precision one.
 

bassbindevil

Joined Jan 23, 2014
52
I was going to suggest a microcontroller, although after a glance at the PIC and AVR selection, there aren't any small/cheap micros with better than 10 bits ADC. But maybe you could work around that by doing auto-ranging or scale the input signal to just the region of interest. Then you get multiple analog inputs, the option for signal conditioning in software, and can send the serial data across an optocoupler with checksums or whatever to ensure data integrity.
 
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