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NNTP-Posting-Date: Thu, 06 Jun 2024 17:57:50 +0000
From: john larkin <jl@650pot.com>
Newsgroups: sci.electronics.design
Subject: Re: AD5791
Date: Thu, 06 Jun 2024 10:57:50 -0700
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On Thu, 06 Jun 2024 10:15:45 -0700, boB <boB@K7IQ.com> wrote:

>On Tue, 04 Jun 2024 10:48:00 -0700, john larkin <jl@650pot.com> wrote:
>
>>https://www.analog.com/en/products/ad5791.html
>>
>>That's an amazing part. 20 bit DAC with 1 PPM accuracy and 0.05 PPM
>>per degree C tempco.
>>
>>My main gripe is its 3.4K output impedance, which makes a lot of
>>Johnson noise. I suppose I could run a bunch in parallel.
>
>
>Nice part but costs way too much for any products we make.
>
>boB

What do you make?

We live on the lunatic fringe of electronics, things that are really
hard to do, things with extreme exponents. It makes money because it
has little competition, but the money is a side effect. I do it
because it's fun.

There must be something cool that we can do with a 1 PPM accurate DAC.

TI has a 20-bit delta-sigma DAC that's about $12, but it's only linear
to 15 PPM. I don't understand how a d-s DAC or ADC can even be that
good. It would seem to need femtosecond edge accuracies inside.