When you find out that a chip you were interested in is obsolete, and no longer made, how do you figure out which chips have replaced it?
I've been having great fun getting hands-on experience with different chips in the 74xx series: plugging them each into a breadboard with a microprocessor, and making a sample project with each.
As I look down the list of 74xx chips, it's clear that some of them have not been made in ages, because they've been completely obsoleted by more recent chips and concepts.
I want to explore the current set of commonly-used parts. If a chip has been replaced by something that gets the job done better, I want to play with that new thing. How would you figure out what that thing is?
For example, the 74116 chip sounds interesting. A simple, no-frills latch? I can see uses for that. But clearly, something better has come along, because as best I can tell, no one makes that chip any more. What's a good way to figure out what has replaced it?
Best Answer
I have a few general obsolescence strategies.
Check the original manufacturer's website and look up the PCN (product change notice). Most big manufacturers will publish these any time there's a meaningful change to a part (new rev, new fab, end-of-life, last-time-buy, withdrawn, etc. They sometimes recommend fit-form-function replacements or migration paths to new devices.
Check other manufacturers and see if there's a cross-reference for the obsolete part (or one of it's manufacturer-suggested alternates).
Do parametric searches for parts in the same family (i.e. opamp) specify the specific (no pun intended) parameters that most concern you (packaging, pinout, power, capacitance, etc.) and see what you get.