[volt-nuts] Building a high resolution DAC

[Dan Kemppainen]

Hi,

20 bits is ~1ppm resolution. 1ppm is pushing stability for most 
references, is it not? I would think that at 24bit or more the reference 
is more of an issue than the DAC itself. As I recall, sub PPM/C 
references already eat up your budget and then some! One would guess 
that as soon the fundamental question of how to build one is answered, 
the details would quickly stack up against you.

If the control loop is very slow (I'm making the assumption this would 
be used as oscillator steering EFC signal...), long term drift in the 
minutes to hours range would be important, and PPM/C becomes more 
critical than noise, as the higher frequency stuff could be filtered out.

A few PPM reference, some PPM resistors, circuit traces and 
temperature/humidity affecting the circuit board could add up VERY 
quickly.

Also, once I clear up a few projects here, I would be interested 
participating in such a project!


Dan




On 8/17/2015 10:29 AM, volt-nuts-request at febo.com wrote:
> That's the next thing. But I will not worry about tempco until
> the fundamental problem is solved:-)
>
> 				Attila Kinali