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.

  • Resolved

ADS131M08: why it can accept AGND – 1.3

Genius 10875 points

Replies: 1

Views: 75

Part Number: ADS131M08

Hi,

1. why it can accept AGND – 1.3(this value is in RECOMMENDED OPERATING CONDITIONS, not ABSOLUTELY MAXIMUM) at VAINxP and VAINxN? I mean, why it can accept negative voltage?

2. The external reference could only support 1.1V to 1.3V range? So it's impossible to use a 3.0V reference like REF3030 to expand it's full scale range?

3. If now the customer would like to measure a single ended voltage signal ranging from 0-2.4V, how can we adjust it to differential voltage signal VIN = VAINxP - VAINxN ranging from -1.2V to +1.2V which meet the FSR just right? Do we have recommended circuit?

  • Howard,

    1. The ADS131M08 has an integrated negative charge pump for a negative supply. This allows for inputs below AGND when using a unipolar supply.

    2. The external reference is limited to voltages from 1.1V to 1.3V. You cannot use a 3.0V source as a reference input.

    3. When the input signal ranges from 0V to 2.4V, we do not have a specific recommended circuit to level shift the input. There are two basic ways that I might try to set the input. First, you could use some sort of voltage divider and divide the input by two. Second, you may try to redo the input signal to range a -1.2V and go to +1.2V. Either solution would depend on the specific sensor that the ADC is measuring. If you have more information on this, maybe we could suggest a better solution.

    Joseph Wu

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.