Voltage vs Current output DAC

[argofanatic]

I've been looking at the AD1853 and AD1852 DACs and I am confused about the outputs of these devices.

The 1853 is specified as "Current Output".
The 1852 is specified as "Voltage Output".

Can someone explain the difference to me and why one would be better than the other.

Thanks.

 

[tschanrm]

I'm not an expert on this, but I think I can give some basic info. Voltage output means it does not need any conversion. You could theoretically connect it directly to an input with just some resistors and caps.

With a current output, you need to convert it from current to voltage. Commonly referred to as "I/V conversion." Opamps can do this, but some people make discrete part I/V conversions. As to which method is better, voltage output or current output, I have no idea.

 

[dsavitsk]

As I understand it, DACs output current. This current must be converted to voltage. DAC chips that output voltage simply have this built-in to the IC. If you look at the datasheet, there will usually be something indicating an opamp onboard the chip.

The difference, then, is that one can build a much higher quality converter by not building it on the chip, so current output converted properly will generally sound beter. A Voltage ourpur chip will generally be cheaper and require less board space.

 

[PatPet]

DAC Architectures

 

[ezkcdude]

You may also refer to this mountain of information (also by way of AD):

http://www.analog.com/library/analogDialogue/archives/39-06/data_conversion_handbook.html

It's a series of seminar notes that was then turned into a book (which I just ordered) called "Data Conversion Handbook" :

http://www.amazon.com/exec/obidos/tg/detail/-/0750678410?v=glance

Happy learning!