Voltage vs Current output DAC

argofanatic · 9th April 2006, 02:58 PM

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 · 9th April 2006, 06:54 PM

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 · 9th April 2006, 07:27 PM

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 · 10th April 2006, 04:09 AM

DAC Architectures

ezkcdude · 10th April 2006, 04:44 AM

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

http://www.analog.com/library/analog..._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...78410?v=glance

Happy learning!

9th April 2006, 02:58 PM	#1
argofanatic diyAudio Member Join Date: Jul 2005 Location: Quebec, Canada	Voltage vs Current output DAC 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.

10th April 2006, 04:09 AM	#4
PatPet diyAudio Member Join Date: Apr 2004 Location: HKSAR	DAC Architectures __________________ DSP Digital Filter anyone?

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9th April 2006, 06:54 PM	#2
tschanrm diyAudio Member Join Date: Nov 2004 Location: Wisconsin	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.

9th April 2006, 07:27 PM	#3
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	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.

10th April 2006, 04:44 AM	#5
ezkcdude diyAudio Member Join Date: Dec 2005 Location: Atlanta	You may also refer to this mountain of information (also by way of AD): http://www.analog.com/library/analog..._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...78410?v=glance Happy learning!

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