This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1294R: Reference Buffer

Part Number: ADS1294R
Other Parts Discussed in Thread: OPA350, ADS1294

Hi Champs,

A customer is using a ADS129xR but he has some tight constraints on the power consumption of the design.

The datasheet states the external reference circuit should look like this:

 

We understand that the fast buffer, OPA350, is essential to provide the current demand for switching capacitance in SAR ADCs but is there also the same justification for this buffer with Delta-Sigma ADCs? Does he run into the same problem as stated here or is this less critical for delta-sigma ADCs:

www.ti.com/.../getliterature.tsp

  • Hello Simon,

    The problem is similar. Instead of demanding charge in bursts for each sample, like the SAR, the delta sigma reference will demand charge once per modulator clock period. On the ADS1294 in high resolution mode, that is 1.95 us. In low-power mode, it is once every 3.9 us.

    Brian