I'm looking through past designs and am trying to reverse-engineer how it was done (explanations not well documented).

I can find the datasheets for the ICs, but I can't find many resources that explain HOW the IC behaves under certain conditions (i.e. Pin 1 goes LOW when xyz and Pin 2 reads when the voltage is 30% of the supply, etc).

Could someone provide me with a resource or two where I can find elementary explanations like these? Here are two of the ICs I'm looking at as an example:
- ISL4223EIRZ
- LM2662M

Thanks!

EDIT: To help you help me, here are a few resources I'm looking through currently for datasheets:
http://www.datasheetarchive.com/
http://www.datasheetcatalog.com/
http://www.datasheets.org.uk/

 

Always go to the manufacturers web site and look for "aplication notes" for the IC your interested in. They usually have a good explanation of the chip, better than the data sheet.