ADS8363 with +-10V signals

Hi Neils!

Since the ADS8363 cannot take the full +/-10V signal directly, you would have to attenuate and level shift your signal to get it into the 0-5V range of the ADC.  The INA159 is designed just for this type of application. 

Hi Tom,

the INA159 looks quite good for single ended input signals and ADS8363 in single-ended configuration.

What Do you suggest for differential input signals and differential ADS8363 configuration?

Regards,
Niels

Hi Neils,

That will be a little trickier if you are still talking about your +/-10V inputs.  The THS4521 could be an option for you though.  Check out this article: http://www.ti.com/lit/an/slyt336/slyt336.pdf

Tom,
I was just asked by my customer if it is possible build a op-amp stage that allows to connect two single ended signals or one differential signal to the ADS8363.

Any ideas?

Regards,
Niels

Hi again Neils!

Absolutely!  The default configuration for the ADS8363 is four differential inputs arranged in two pairs, A0/1 and B0/1.  You could use the A0 channel (for instance) as the differential input with the THS4521.  You can then use two of the INA159 devices on channels B0 and B1 (absolute arrangement would be based on which channels, if any, need to be simultaneously sampled).  To use the B channels with the single ended signals, you just need to tie the 2.5V reference back to the unused input.  The picture below provides an example hookup for the single ended inputs.

Tom,

unfortunately, I need all ADS8363 inputs. It will look like this:

Do you have an idea how to implement the big "?" in my drawing?
May it be possible to just use eight INA159? Will this work for differential input signals?

CMA and CMB have to be connected to Vref?

Regards,
Niels

Hi Niels,

I'll send along an e-mail to the address in your profile with some suggestions on how you might implement the combination of both single ended and differential inputs.  The CMx inputs are optional - there are settings in the REFCM register (see page 27) for using either the internal reference or the CMx inputs.

Hi Tom,

please have a look at the following picture:

I think it is possible to digitize either one differential +/-10V input signal or two single ended +/-10V input signals with this "double-INA159"-op-amp-stage.
I am aware of the need to reconfigure some registers in the ADS8363, depending on whether I connect single-ended or differential input signal(s).

Do you agree?

Regards,
Niels

Hi Tom,

sorry for the delay, and many thanks for this great piece of support.

Regards,
Niels