HELP!! ANALOG TO DIGITAL CONVERTER SCHEMATIC DIAGRAM?

Most ADC's are on chips, are somewhat complicated in design, and are proprietary to the manufacturer, so schematics aren't readily available. The schematics are rarely if ever printed out on a piece of paper or pdf file, and are mostly in the form of Cadence schematics in software, with the various blocks of the converter having its own schematic. And even if one could see the whole converter as a bunch of transistors, passive components and lines/wires, one would get easily confused as to where the blocks are and what does what.

You might be able to find a simple one on your favorite search engine by typing something like "building your own ADC" or "discrete ADC project". And then be aware that there are many types of ADC's as well. SAR(successive approximation register) converters tend to be the most popular. But here are also pipeline, sigma-delta, flash and so on. Actually, the simplest one for a hobbyist may be a flash converter. So perhaps search for "build your own flash converter". They're basically just a resistor ladder, with each point in the ladder going into the negative input of a comparator, the signal of interest being tied to the positive input of all the comparators, and then the comparator outputs going into an encoder.

Read this link...........

http://www.analog.com/media/en/technical-documenta...

One piece IC called AD7993 can do.