[sdiy] Static ADC and DAC recommendations?

[Neil Johnson]

Hi,

cheater cheater wrote:
> Right, flash converters were my first bet too. For example the ADC0800
> (which is the pair chip to the DAC0800) is the same as the MC10319
> which you recommend. This type of chip is not suited to what I'm
> trying to do.. it has latches and other digital logic that I don't
> want. In addition, they're there so that the output is glitch-free etc
> - I don't need that either (in fact, glitching is desirable here..).
> There must be a chip which is even more primitive than flash
> converters. I'm sure someone built n comparators and fixed ratio
> transistor amplifiers into a single piece of silicon before..

Why would they?  Heck, even the venerable and ancient CA3306 requires
a clock.  A flash converter is a large expensive piece of silicon (you
need one comparator per level, so 8 bits = 256 comparators).  That's a
lot of silicon, and to remove jitter you clock the output.

There's an interesting historical write-up on flash converter's in
this ADI document:

http://www.analog.com/static/imported-files/tutorials/MT-020.pdf

I particularly like figure 9 - nice layout of ECL comparators!

If you really want jitter and other crap then you'd probably be better
off building your own flash converter out of comparators and a
resistor chain.  You'll also need the priority encoding logic to map
the converter outputs down to 8 bits (or however many bits you want to
play with).

Neil
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