I am looking at purchasing a 14-bit ADC chip (http://www.farnell.com/datasheets/1882573.pdf) for a battery monitoring project that I am working on, and am using a differential amplifier measuring voltage across a current shunt and then feeding that into an ADC.

Would this potentially work if I just used the output of the diff amp (1-5V) and into the +in pin and ground into the -in pin? If not, why not?


1 Answer 1


Would this potentially work if I just used the output of the diff amp (1-5V) and ground into the +in and -in pins? If not, why not?

What you have said above makes no sense - with both input pins grounded, the device won't work. Probably what you want is reassurance that the device can work single-ended (as per your question title. The data sheet quotes this: -

For single-ended operation, the > non-inverting input (+IN) of the ADC141S626 can be driven with a signal that has a peak-to-peak range that is equal to or less than (2x VREF). The inverting input (−IN) should be biased at a stable VCM that is halfway between these maximum and minimum values. In order to utilize the entire dynamic range of the ADC141S626, VREF is limited to VA / 2. This allows +IN a maximum swing range of ground to VA. Figure 40 shows the ADC141S626 being driven by a full-scale single-ended source.

This is on page 16.

  • \$\begingroup\$ sorry that was poor phrasing, what I meant was output of the diff amp into the +in and ground into the -in. \$\endgroup\$ Mar 10, 2015 at 12:08
  • \$\begingroup\$ I did read that section actually, I should have been more succinct in my question. What I was trying to attain more was can I expect normal operation just by applying my signal into the inputs (single-ended as it may be), or if not, is there a way to use a differential input from my measurement somehow? \$\endgroup\$ Mar 10, 2015 at 12:17
  • \$\begingroup\$ As is probably apparent, I am not fully savvy with ADCs, and didn't fully understand that section that you quoted. Would it be correct to say that with a Vref of 5V and a diff input, the ADC could read values from -5V to 5V? \$\endgroup\$ Mar 10, 2015 at 12:32
  • \$\begingroup\$ Using the method in the data sheet should be ok but there might be a slight increase in noise on the digital values converted. \$\endgroup\$
    – Andy aka
    Mar 10, 2015 at 12:32
  • 2
    \$\begingroup\$ Look at figure 41 and figure 42. Neither input should go below 0V - inputs need to be biased positively - it is not a true bipolar differential input. \$\endgroup\$
    – Andy aka
    Mar 10, 2015 at 12:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.