Jellybean logic chips

On Mon, 16 Jan 2012 15:39:08 -0800 (PST),BillSloman









bill.slo...@ieee.org> wrote:
On Jan 16, 6:11 pm, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net> wrote:
BillSlomanwrote:

On Jan 16, 4:55 pm, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net> wrote:
On 01/16/2012 06:21 AM, petrus bitbyter wrote:

"hamilton"<hamil...@nothere.com>  schreef in bericht
news:jevd34$mk6$2_at_dont-email.me...
On 1/15/2012 11:21 AM, petrus bitbyter wrote:
a7yvm109gf...@netzero.com>   schreef in bericht
news:a76c9327-b45c-4fb0-8217-fc0e5af61f2d_at_m20g2000vbf.googlegroups.com...
Hi all, (happy new year BTW)
How are 74xx chips made these days? Just the same old masks as 30
years ago, or are they die-shrunk along with everything else? I doubt
manufacturers keep vintage equipment going just to make old ICs, and I
also don't think the die is the same size.

If I crack open a 30 year old 7400 and a recent one, will the die be
the same size?

What are the chances that modern 74xx devices are actually a single
CPLD that's programmed at the factory to act like a 7400 or 7406?

Just daydreaming here.

TIA

Recent one? Standard TTL is obsolete for years by now and FAIK it is not
produced anywhere anymore.

Go over to Digikey.com and enter 74ls into the search box.

Maybe not as many as a few years ago, but still hundreds of parts still
available.

And Digikey only sells what is currently available.

Standard TTL are the parts numbered SN74xx or some SN74xxx and equivalents.

The parts numbered SN74LSxx are LOW POWER Schottky TTL. Most of them are
still widely available.

There are still some more specialized original TTL parts, especially the
ones with higher drive, e.g. the SN7406 OC inverter/driver.  There was a
time back in the 80s when it still made sense to use old TTL for that
sort of job, because the LS ones were too wimpy.  I suspect that it's
mostly repair and maybe residual production of those sorts of gizmos
that keeps old TTL going.

As with the 555 - legacy designs and legacy designers, plus the
occasional good fit in an odd situation.

I usually associate the word "legacy" with good things, such as a
long-lost uncle leaving me lots of money.

"Legacy" designs are circuits that were designed a long time ago, and
still work well enough that nobody is going to pay to update the
design for more modern parts. "Legacy designers" recycle old
designs and old parts, because they know they work, and the product
isn't going to sell in the kind of volume where the money you could
save by designing in new parts would to cover the extra cost of
working out a new design and getting the bugs out of it, or because
they are lazy.

In the industrial automation sector, you are typically required (by
contract) to supply spare parts for at least a decade.  In practice,
in order to keep the customer (for new orders), you have to support
systems two or three decades old.

When old components are no longer available, you have to design new
boards with current components so that a board or box level
replacement can be done.

Why doesn't somebody make the mosfet equivalent of the ULN2003?

John Larkin wrote:

Why doesn't somebody make the mosfet equivalent of the ULN2003?


No need for one?

On 1/25/2012 10:52 AM, Michael A. Terrell wrote:

John Larkin wrote:

Why doesn't somebody make the mosfet equivalent of the ULN2003?

No need for one?

Allegro did make a replacement with a single bipolar output stage for
improved efficiency.

We just sold out of these.

On 1/25/2012 10:52 AM, Michael A. Terrell wrote:



John Larkin wrote:

Why doesn't somebody make the mosfet equivalent of the ULN2003?

    No need for one?

Allegro did make a replacement with a single bipolar output stage for
improved efficiency.

We just sold out of these.

They were a great student proof I/O.