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I am trying to use ADS1252 ADC with Arduino. I got following schematic from git of a breakout board for ADS1252

ADS1252

Now there is only one pin dedicated to input signal whereas I want to use this board in differential input mode.

Questions:

  1. Is it possible to use this circuit in differential mode if I give SIG2 to inverting terminal of U2 ?
  2. why is this configuration of OPAMPs used between SIG and ads1252 input pin?
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  • \$\begingroup\$ It looks to me that the ADC is running in diff mode. The input amps you see provide a converting stage to transform a uni-polar single-ended input (~0-5VDC) to a differential input to the ADC. A strategy to boost resolution. This circuit is not designed to accept a differential signal as an input. It may be possible to hack the design if needed (you would need to cut some traces). Do some more googling. \$\endgroup\$ – Chris Knudsen Jun 5 '17 at 21:16
  • \$\begingroup\$ @ChrisKnudsen so it's fairly simple then I just need to connect differential signals to VIN+ and VIN- of ADC. Also about the circuit..Is it for noise reduction ? \$\endgroup\$ – Mr.Sky Jun 5 '17 at 21:19
  • \$\begingroup\$ Also, R5 should not be a 0-ohm resistor. It could however, be a 'none'-resistor :) \$\endgroup\$ – Chris Knudsen Jun 5 '17 at 21:21
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    \$\begingroup\$ Re, the circuit as is: No, it is a single-ended to diff converter. It allows one to connect a native single-ended signal to a differential converter. It will help with the resolution of the conversion of the single-ended signal, and that's about it (there is some minor filtering going on, but nothing terribly aggressive). You'll be fine to not implement this circuit, if you already have a true unipolar differential signal (be certain that you do!). A true unipolar differential signal will have two signal wires. The signal on one will mirror the other. Only positive voltages. \$\endgroup\$ – Chris Knudsen Jun 5 '17 at 21:28
  • \$\begingroup\$ @ChrisKnudsen ooh so that's what it for (I thought it was some kind of hardcore noise reduction black magic thing)..... Now I understand it completely !! Thanks, man !!!:) \$\endgroup\$ – Mr.Sky Jun 5 '17 at 21:34
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It looks to me that the ADC is running in diff mode. The input amps you see provide a converting stage to transform a uni-polar single-ended input (~0-5VDC) to a differential input to the ADC. A strategy to boost resolution. This circuit is not designed to accept a differential signal as an input. It may be possible to hack the design if needed (you would need to cut some traces). Do some more googling.

Re, the circuit as is: No, it is a single-ended to diff converter. It allows one to connect a native single-ended signal to a differential converter. It will help with the resolution of the conversion of the single-ended signal, and that's about it (there is some minor filtering going on, but nothing terribly aggressive). You'll be fine to not implement this circuit, if you already have a true unipolar differential signal (be certain that you do!). A true unipolar differential signal will have two signal wires. The signal on one will mirror the other. As one signal goes from 0 to 5, the other goes from 5 to 0. Only positive voltages, and be wise to stay away from either rail, 0 or 5V (Consult the datasheet of the ADC). In addition, there should be a ground reference from your signal circuitry to the ADC ground.

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