Low value R "I/V" with the PCM1738...

[AW]

Low value R "I/V" with the PCM1738...

...type of DAC?

Older Iout DACs were ground referenced so it was easy - but these things sit the Iouts up at half rail - which makes life a tad difficult if you want to do it KISS style.

I can see how to do it differentially - by running the R between the + and - current outputs and taking a differential signal from across them - but without using an opamp (which I hate) or a transformer (which I also hate - but not as much as opamps) it's more complex than i wany.

And you can't take the R to gnd and have the DAC survive - don't ask me how I know...

Anyone made this work simply?

Allen

 

[Jocko Homo]

Somehow I don't think that they had KISS in mind when they designed it...............

I suppose that you could make a voltage reference, bias it up at Vcc/2......isolate it with a big resistor..............tie that to 2 smaller I/V resistors tied together...take the other end of them to the +/- outputs.

But I would go for active stage that didn't need an op-amp, because that is what I do best.

BTW.......I know that some DACs won't work if you don't use a load to ground. Don't ask how I found out by forgeting to hook up which wire and when................

Jocko