IV for PCM1730

[MWP]

Hi all...

The PCM1730 has balanced current outputs labeled as IOUT+ and IOUT-.

The PDF shows a "typical" IV stage which consists of a opamp based IV for each half of the output followed by a summing opamp.

I wish to stick to opamps for the IV (OPA637's), but was wondering if i can use only one half of the output which will cut the number of opamps needed.

I found a web site which shows the same DAC with this output stage:

An externally hosted image should be here but it was not working when we last tested it.

Will i be comprimsing the quality of the DAC by only using 1/2 of the output like the diagram above?

 

[ftorres]

Not quite related, but have a look at this thread I tried to start 🙄. Haven't had the time to test it, but I'm still considering using this chip.

 

[peranders]

I wish to stick to opamps for the IV (OPA637's), but was wondering if i can use only one half of the output which will cut the number of opamps needed.

OPA637 is not intended for low gains. Use OPA627 instead if you have gain < 5.

 

[MWP]

I think im just going to go with the original circuit.
Will be a pain to route on the PCB as it will be using 8 separate 8pin opamps... but its all part of the fun 😉

 

[Petter]

Half the output:

Yes as you have drawn it, quality will suffer. However, if you require only single ended outputs use Iout+ and Iout- on a fully balanced op-amp such as THS4131. You probably don't even need the output buffer, and you certainly don't need R6,7 ...

Petter