To divide an input voltage by about 10 as well as reducing the impedance , I came across 2 possibilities: a buffered voltage divider (top) and an inverting amplifier (bottom).


simulate this circuit – Schematic created using CircuitLab

It is not a problem to invert the signal (the input voltage is itself both negative and positive) and both circuits are using the same components, so they look the same for me. What should I consider to pick one of those circuits in my design?

To give a little bit more information about my requirements:

  • Input voltage: -25V to +25V
  • Bandwidth: DC to 10kHz
  • Op Amp supply: probably +3.3V and -3.3V
  • 7
    \$\begingroup\$ I personally prefer the inverting solution because there the opamp's inputs are always at ground level as opposed to the non-inverting solution where the inputs follow the output voltage. So with the inverting solution you can choose an opamp with a more limited commonmode input range and commonmode rejection might be less of a problem. \$\endgroup\$ – Bimpelrekkie Feb 8 '17 at 9:44
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    \$\begingroup\$ On top of FakeMoustaches comment, the non-inverting option has a slightly higher input impedance (R1 + R2 Vs R3). If you are genuinely going to use parts in the 5 MOhm range that's not going to be an issue, if you end up using lower values it may matter depending on the signal source. To be honest unless you're in some highly sensitive special case situation you will probably be hard pressed to find any meaningful difference in performance between the two. \$\endgroup\$ – Andrew Feb 8 '17 at 10:01
  • \$\begingroup\$ Thank you both of you for the useful information. Could you please transform them into a proper answer so I could accept it? \$\endgroup\$ – Edesign Feb 13 '17 at 13:33

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