DACs with or without internal Reference?

[mImoto]

Hello,

I am looking for DACs (similar to the TI Tlv5623). I have seen that for example this one should have an external reference of about 2 volts. then it has a x2 amplifier inside.

Analog and some others have DACs with internal reference programable.

I don't know which is the reason for having an external reference, why not the designers use directly the 5V as internal ref. and then no x2 amplifier. I know I am forgetting something, maybe technology reasons.Could someone clarify me my doubts? and also which is better Dacs wit internal or with external reference?.

Best regards,

mimoto

 

[trader]

Take a look at Maxim MAX5383/Max5384/Max5385 ht*p://pdfserv.maxim-ic.com/arpdf/MAX5383-MAX5385.pdf It's 8bit DAC with 3wires interface and has internal voltage reference equal to 0.9 x VDD, the DACoutput will vary with the power supply.
External refernce gives you more flexibility since you can set it at any voltage that less than VDD, and with precision voltage reference, the DAC output won't vary with the supply.

 

[samsuffy]

The supply voltage (5v ?) isn't used because it can be noisy and make wrong the conversion.

 

[mImoto]

So then I you require a precise Vreference is better external, other else I understand that is better DACs with internal reference, isn't it?.

Thanks for the info,

mimoto

 

[papyaki]

Hi

External voltage references are noise less as wrote samsuffy, but also have better temperature compensation and long time stability as internal ref.

Read this excelent article from Maxim on how to choose an external reference : **broken link removed**

 

[flowers]

Try **broken link removed**.

It has great temperature drift.

 

[bunalmis]

Some times external referance input usuable for modulation.