ad5323 using as programmable attenuator

Question

1. I supposed to use 'REF' as input pin. Also, the noise of this input signal is already known. However, I don't see any information about how much noise this DAC may contribute. So I want to know does this mean DAC won't contribute any noise or how can I calculate this noise. 
 2. I have noticed that most of your DAC chips are based on the principle of resistance net according to datasheet. Do you have any charge redistribution DAC? Cause I think capacitor would have better noise performance than resistance.

isantos · Accepted Answer

Hi, 
 1) As AD5323 does not have any information on noise performance/spec, would you consider using AD5687 ? You can find the noise specs under AC characteristics of the datasheet. More info on NSD can be found on this tutorial and this video . 
 2) I'm pretty sure capacitance based DACs have its advantages (and disadvantages too) on some applications, however in the precision space we currently offer resistor based architectures. 
 Cheers, 
 Ivan)