Current Output DAC vcs Voltage Output DAC.....

Hi!

I don't know whether i can ask this question here or not. i have 2 questions current output DAC.

What is the difference between the Current Output DAC and Votage Output DAC.
if we take Current Output DAC means, in it How voltage will be related to current. whether voltage existing there or else not existing......
as a fundamental law the voltage will exist when current exists unless it is open circuit.
and another thing is......
if i use a i-to v converter to convert the current to voltage the relation will be
v = -iR
by changing the R (feedback resistor) we can get whatever gain we want.....How much we increase R so, that performance will not be degraded...i mean if Iout =0.56ma(Output curret from DDS) then can we increase the voltage to 10V with just a i-to V converter without using any amplifier....whether it is possible....

if any body can answer it will be great help to us...

waiting for reply...

1) Current Output DAC:

As the name says, output is current instead of voltage. However this current flows only when you connect a resistor between output pin and ground. This allows you to choose the circuits gain through the resistors value, within certain limits of course. V = R * I, like you said.

2) Resistor values:

Large load resistors don't work well because they will make the circuit to saturate, since output voltage cannot exceed VCC.

Small resistor values won't work well either because they will require more current than the current the circuit can provide (output impedance), and output amplitude will be smaller than the theoretical value espected.

Datasheets usually specify this maximum and minimum values or, at least, typical value. Using resistor values a lot different of those specified in the datasheet will reduce the circuit's performance, increasing distortion, saturation, etc.

thnQ,

what i want to ask is,

whether it is Current Output or Voltage Output , there will be definitely 1 or 2 output pins.
if current output if we connect resistor to that pin we will current from that pin and voltage will be developed.
if Voltage Output also we can generate current from it definitely.
So, anyway whether it is voltage output or current output definitely current and voltage exists. then what is the difference

thnx

The difference is that with current output you can set the gain through the resistor:

Vout = Iout * R

With voltage output you cannot set the gain but you don't need the resistor either.