[sdiy] selecting a semiconductor manufacturer

[groovyshaman]

Interesting... being a relative newcomer to analog EE I've always been
curious about this subject of different IC manufacturers and whether there's
any significant differences between them.  Especially since the data sheets
nearly all look alike for a given legacy part.  I thought I remembered
reading a comment Bob Pease made in one of his articles or books that "data
sheets lie" or some such.  So what then can one go by other than experience,
or the shared experiences of others?

In the cases where the data sheets are the same across manufacturers, I
wonder if the masks and materials are *really* all the same as well, and if
not, if there might not be some slight side effect that a 2nd source part
might have in a given circuit where the original manufacturer's part would
work perfectly.  For example, I remember reading on this list that the
Fairchild 4051 has some potential latch-up issues compared to other
manufacturers, again, depending on the circuit.

Also, there seems to be some mystery (aka my lack of knowledge!) about the
original NE5532 (a Phillips part?) and it's sound quality compared to the
current crop of 2nd source'ers like TI and what not.  I've read that the
original factory and masks were lost in a fire some years ago and that more
recent parts (that use copies of copies of masks?) do not sound the same.

And another one is the JRC4558 vs the newer RC4558 parts.  Is this all snake
oil??

A big source of confusion for me is that prices for a given part are usually
all over the map.  I've noticed that when a part originates with a
particular manufacturer (say the National LM324) their price is often higher
than any other 2nd source parts.  Makes you 2nd guess yourself.

In the end, since I'm not really equipped to make knowledgeable decisions
between most of these parts, I usually just try to find the lowest
price-at-quantity for the original manufacturer of a part, and if the 2nd
source part is more than say 25% cheaper, I'll get the 2nd source.  And
since I greatly respect the comments of listmembers here I therefore try to
heed any prior advice on the subject.

Hey Harry, what about those new-old BBDs?  Bet they still sound like s#^t!
;-)

-George

----- Original Message ----- 
From: "James Patchell" <patchell at cox.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, May 17, 2005 8:33 PM
Subject: Re: [sdiy] selecting a semiconductor manufacturer


> I am also dubious about the quality of parts that NTE sells...definitely
> correct me if I am wrong in my impression...
>
> As far as the other in the list...I have never noticed anything
> significantly different between the major manufacturers.
>
>          -Jim
> ***************************************************************
> http://www.oldcrows.net/~patchell