Best to ask volt-nuts?
On Mon, Aug 17, 2015 at 3:16 PM, Attila Kinali <att...@kinali.ch> wrote: > Hi, > > I have been pondering how to build a high resolution DAC over the weekend. > Something like [1] but has the disadvantage of needing a pair of resistors > that have a 1:2^16 ratio. The 1M/15.4R is kind of unwieldy. > Fidling around a bit, I came to the conclusion that using an R-100R ladder > with 4 10bit PWM DACs would be a good solution. 100R and 10k resistors > are readily available in 0.1% 25ppm/°C (and actually quite cheap). > While the first stage gives 10bits, each additional stage gives > approximately another 7bits, resulting in a total of 29bits resolution. > The 3 remaining bits per stage can be used to linearize the whole > circuit. > > Now this is where the problem starts. How do I measure the circuitry > to build a linearization table? The linearity error is dominated by > the first stage error which is in the order of 0.1% and thus 10bits. > It would be necessary to measure this to somewhere close to 29bits, but > the best DACs that are readily available are 24bit. Yes, there is the > possibility to build some ADC that could do 28bit, but I am not exactly > keen on building something aking an HP3458 (mostly to avoid the > embarrasment of failing at doing so). > > So, the question is how would one calibrate something like this? > Or am I missing something fundamental here? > > > Thanks in advance > > Attila Kinali > > [1] "DC-accurate 32-bit DAC achieves 32-bit resolution", > by Stephen Woodward, 2008 > > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neil Stephenson > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.