Converting Current output from DAC to voltage using op-amp

[pavjayt]

Hello,

I have a reference design to do DAC current output to voltage conversion shown in the attachment. It is taken off of a spreadsheet downloaded from either TI or Analog didnt remember exactly. Works fine for the values that it generates by the outputs are not exactly as calculated. The spreadsheet calculates all R values except Rf, R3 (supplied by the user, along with Vref and Vout). We are using this design with the outputs from DAC5672. For example, if I design it according to the values generated by the spreadsheet for say Vout = 4Vpp using THS3091, I am getting about -1.889V to 1.980V. I dont mind the discrepency, but would like to know which R(s) I need to tweak to adjust this for any given Vout. I have a prototype board with potentiometers for all resistors.

thanks in advance.

 

[cowboybob]

I'm really just guessing, but the circuit looks like it would respond (as you wish) by adjusting Rx and/or Ry, thereby altering the voltage division ratio.

 

[AnalogKid]

Neither your post nor the schematic have *any* resistor values. Exactly what kind of advice do you expect? Please post *your* schematic with your resistor values.

ak

 

[pavjayt]

Neither your post nor the schematic have *any* resistor values. Exactly what kind of advice do you expect? Please post *your* schematic with your resistor values.

ak

Here you go, I was just asking the question in general. If schematic helps, that's great. The names in bigger font refer to the ones in the reference design.