Setting V+/V- supply

Hi LTM4712 ,

Based on the info from the datasheet you've mentioned and your specifications (V+ = 5V, V- = -4.5V, 50μA load current), your desired output range of -3.5V to 2V should be achievable. The datasheet guarantees performance for load currents between -10mA and +10mA. With these supply voltages, the DAC can swing from -3.1V (V- + 1.4V) to at least 3.6V (V+ - 1.4V), well within therequired range. However, while these calculations suggest compatibility, it's crucial to validate the DAC's performance in your specific application to ensure it meets your precise requirements, especially considering the low current load and the precision nature of your design.

Br,

Den

Hi LTM4712 ,

Based on the info from the datasheet you've mentioned and your specifications (V+ = 5V, V- = -4.5V, 50μA load current), your desired output range of -3.5V to 2V should be achievable. The datasheet guarantees performance for load currents between -10mA and +10mA. With these supply voltages, the DAC can swing from -3.1V (V- + 1.4V) to at least 3.6V (V+ - 1.4V), well within therequired range. However, while these calculations suggest compatibility, it's crucial to validate the DAC's performance in your specific application to ensure it meets your precise requirements, especially considering the low current load and the precision nature of your design.

Br,

Den

 "With these supply voltages, the DAC can swing from -4.5V (V-) to at least 3.6V (V+ - 1.4V)"

Why can swing from -4.5V to 3.6V,1.4V does not affect V-? If 1.4V affects to the output the swing would be from -3.1V (-4.5V+1.4V) to 3.6V (4.5V-1.4V) instead of -4.5V to 3.6V, right?

Hi LTM4712 ,

Apologies for the oversight, yes you're correct the 1.4V headroom applies to both the V+ and V- rails, therefore the output swing will be from -3.1V to 3.6V. (edited the original response for correction)

Br,

Den

Okey so, in case my output swing is -3.1V to 3.6V, to calculate my digital value desired I must take into account -3.1V to 3.6V as min and max voltage reference or the internal reference +/-5V? I mean, if I want a Vo = 0V The formula would be Dig Val=((Vo-Vmin)*2^n)/Vrange

Which one would be okey, Dig Val=((0-(-5V))*2^16)/10=32768 or Dig Val=((0-(-3.1V))*2^16)/6.7=30323? 

I guess it does not matter the voltage swing, the voltage range will depend on the internal reference although the output does not reach the full scale but I would like to make sure.

Yes, it needs to be aligned with the DAC's full-scale range.