Chip finder?

[Sky King]

Is there a web site that will cross reference chip numbers? I have
some older designs I would like to build, but the chips they list are
no longer made. Any help will be helpfull.

Thank you,
Sky King

 

[Michael Black]

On Mon, 21 Apr 2008, Sky King wrote:

Is there a web site that will cross reference chip numbers? I have
some older designs I would like to build, but the chips they list are
no longer made. Any help will be helpfull.

Do a search for the nte replacement guide, it's a line of "universal"

components with a cross-reference.

Though, as I was reminded recently when I looked for something for
someone, the guides fail if the devices are too old. After a while
older devices are dropped and the cross-references dropped too. So
you can't even use the cross-reference for it's most important use,
getting some basic information on a device.

Just try websearches on old devices, sometimes you can find pages that
give information. Go to amateur radio club fleamarkets and buy old
databooks (usually they go cheap), and become more definitive sources
of information than second hand sources. They can often be useful
in themselves, since a lot of secondary books pull information from
manufacturer's databooks.

Of course, the components that can be directly replaced use standard
numbers, though sometimes the prefixes or suffixes vary from manufacturer.
A PN2222 is basically the same as a 2N2222, for instance, with the former
having a plastic case and you should be careful if the device is used
close to its power limits. On the other hand, once you grasp this about
prefixes, a good but not consistent rule, you should be able to find
data about common devices. Likewise, op-amps tend to have standard pinout
and multiple sources (though again different prefixes), and for a lot of
general work a handful of op-amps will serve the purpose. Of course,
you do need to know when an esoteric op-amp is specified, since there
usually is a good reason why someone specified it. The logic families
are pretty standard, too.

Of course, it helps to know why specific parts are used. Sometimes there
are really good reasons, but for hobby purposes it's often a case of
either using things that are commonly available (which means a small
number of devices get a lot of use), or specifying a part that can
easily be had. I remember being fourteen and someone at high school
spending lots of money on a replacement line op-amp, and when I said
it was a common op-amp and lots of other ICs could be used there, he
said "I don't want to make any errors". The article specified the
replacement line part since chances were good one could get it locally,
the device it replaced was just as good or better.

The more integrated an IC is, or the more specific its intended purpose
was, the harder it will be to find a direct replacement. Unless there
is a second source of the device, there at best will be functional
equivalents, that may require changes in pinouts or external components,
or even a complete redesign because the alternative is just sort of like
the original. More recent and fancy ICs, chances are good that unless
you can get the device, you need to look at some other circuit, since
there will be no easy way to use an altnerative.

The more you know about electronics, the easier it is to sort things
out.

And sometimes if the circuit is too old, there is no real point in
using it, unless you actually have the parts on hand. Take just
about anything, and it's been written about numerous times, and if
the devices are hard to get, then a more recent schematic that does
the same thing is likely quite available, using still available devices.
More recent circuits may be better anyway, because an old circuit
would mean not just finding one hard to find device, but then you discover
you need that coil that's no longer being made, and the circuit doesn't
really say much about it other than the part number, so you're stuck
there too.

Michael

 

[Bob Monsen]

"Sky King" <aaron_stansbury@yahoo.com> wrote in message
news:f369c5c2-3e20-4555-872b-5a413cb0a9ef@x41g2000hsb.googlegroups.com...

Is there a web site that will cross reference chip numbers? I have
some older designs I would like to build, but the chips they list are
no longer made. Any help will be helpfull.

Thank you,
Sky King

The nte site has one, but I wouldn't buy their parts, since they are so
expensive.

http://www.nteinc.com/

Regards,
Bob Monsen

 

[JeffM]

Sky King wrote:

I have some older designs I would like to build,
but the chips they list are no longer made.

The Universe is pounding on your door trying to tell you this is a bad
idea
and you won't acknowledge it.
Just because you found someone's circuit from 1975
that says it will do what you want
doesn't make that the best plan to pursue.

There is a reason that projects using Coherers or Audions
are considered deprecated notions.
It's the same with obsolete integrated circuits.

Put your efforts into finding a more recent implementation of the idea
or post about what you are trying to accomplish and ask for help with
that.

 

[John Fields]

On Mon, 21 Apr 2008 12:11:52 -0700 (PDT), Sky King
<aaron_stansbury@yahoo.com> wrote:

Is there a web site that will cross reference chip numbers? I have
some older designs I would like to build, but the chips they list are
no longer made. Any help will be helpfull.

---
You might try posting the schematics to
alt.binaries.schematics.electronic.

That way, once we see what's going on, we might be able to guide you
with regard to your available choices regarding a more modern
implementation of the device.


JF

 

[Sky King]

On Apr 21, 7:35 pm, John Fields <jfie...@austininstruments.com> wrote:

On Mon, 21 Apr 2008 12:11:52 -0700 (PDT), Sky King

aaron_stansb...@yahoo.com> wrote:
Is there a web site that will cross reference chip numbers?  I have
some older designs I would like to build, but the chips they list are
no longer made.  Any help will be helpfull.

---
You might try posting the schematics to
alt.binaries.schematics.electronic.

That way, once we see what's going on, we might be able to guide you
with regard to your available choices regarding a more modern
implementation of the device.

JF

Thanks for all the help and info. I will try the ideas posted.
Thanks again.

Sky King