Analog use of CMOS logic chips

Hi Active8,

projects? IOW, is it a


^^^^^^^ corrected


safe career move to go into chip design?


^^^^^^^ corrected

"Safe" as in "job security" and "not having to work cheap even if
we're the best". Now what would you say?
Click to expand...
Yes, that would be it. For a young engineer these can be tough
decisions. A while ago I read about a project in China where they had
created their own CAD tools (Panda) for chip design. That was a pretty
good surprise.

The family rule is simply do what
makes you happy, BUT with the proviso, be the best.



Right. Being the best can go a long way.
Click to expand...
Unfortunately that ain't always the ticket. These days companies often
don't go after the best. They look for 'just good enough but cheap'.

An engineer who worked in HVAC control gear already felt that 'spirit'
more than ten years ago. He suggested to switch to an 8bit micro
controller because that would open up some more fancy applications.
Nope, was the answer. Not as long as the Asian 4bit uC costs a few
pennies less.

Regards, Joerg

http://www.analogconsultants.com
 
Joerg wrote:

Thanks for sharing this part of CMOS logic history. It's kind of sad
that many of these devices never really made it.
Click to expand...
Very sad. I also greatly miss HNIL (high noise immunity logic),
now sadly found only in acronym/abbreviation lists. :(
 
Joerg wrote:

It was the thermostat he designed. Realtime clock, programmable, LCD,
the whole nine yards except for the remote. With a four-banger in there.
Click to expand...
The only reason I use cheap 4-bit chips is because nobody makes
even cheaper 3-bit chips... :)
 
Hi Ken,

Four bits luxury! We had to do our designs with only one bit and were
happy to have that.


BTW: There really was a one bitter, the 14500.

The company I work for was one of the first to even make a multiprocessor
system. The system had 3 4040s in it. They were over clocked so they
really zipped along at about 2.2MHz.
Click to expand...
I had heard of a one bitter but, quite frankly, never believed that it
had a commercial use. Seems it did.

The four bitters are only in the products for price. Come to think of
it, a price tag of around 50c to $1 for a bare bones uC is kind of
steep. Many times I have designed stuff with logic and discretes just
because that was a little lower in cost than a uC solution. With caps
and resistors the size of a grain of salt size wasn't any larger either.

Regards, Joerg

http://www.analogconsultants.com
 
jdurban@vorel.com (Product developer) writes:



As you can imagine the rider peddles and peddles getting up to a good
speed and as he and eventually the cart in tow, traverses the ELF
field the cart comes to a hard stop and the rider took flight over the
handle bars.

I would have flown out there to the store with my DV Cam in hand if I
had known in advance. You just can't buy this kind of product testing!
Click to expand...
What stopped people from lifting the cart across the loop. or tilting
it if only one wheel was active? Was signal necessary to keep the
wheel unlocked?



--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
 
In article <Ywbmd.44507$QJ3.37685@newssvr21.news.prodigy.com>,
Joerg <notthisjoergsch@removethispacbell.net> wrote:
[...]
It was the thermostat he designed. Realtime clock, programmable, LCD,
the whole nine yards except for the remote. With a four-banger in there.
Click to expand...
Four bits luxury! We had to do our designs with only one bit and were
happy to have that.


BTW: There really was a one bitter, the 14500.

The company I work for was one of the first to even make a multiprocessor
system. The system had 3 4040s in it. They were over clocked so they
really zipped along at about 2.2MHz.

--
--
kensmith@rahul.net forging knowledge
 
Joerg wrote:

The four bitters are only in the products for price. Come to think of
it, a price tag of around 50c to $1 for a bare bones uC is kind of
steep.
Click to expand...
10 cents is steep.
 
Hi Jim,

Aren't 74xC... parts dirt cheap? And their smaller feature size means
they consume less power for a given toggle speed.
Click to expand...
They are dirt cheap but many times the respective CD4000 part is still a
tad cheaper. In consumer products one penny can make all the difference.
Also, CD works up to 15V, sometimes 18V so you can run it off a 12V lead
acid battery or a 9V block without any regulator.

Might be interesting to post some CD4000 series circuits (operated at
= 5V) and compare power consumption/performance with modern parts.
Click to expand...
I never design with CD4000 under 6V because their performance becomes
very sluggish. That's clearly the 74HC domain. But they don't offer
stuff like a CD4007 in that technology. There would be a market but only
if the mfgs see it and only if the engineering public would be educated
about its many uses.

For really slow stuff like a 4060 timer I could see an operation of
CD4000 logic under 5V, or if you wanted to use them for slow analog
jobs. But not for anything in the MHz range.

Regards, Joerg

http://www.analogconsultants.com
 
Product developer wrote:

I designed a 60 to 70db gain amplifier drawing only 10ua out of the
4007 back when rail to rail micro power and low voltage opamps were
still on the drawing board.
Click to expand...
Maybe- but a single stage discrete transistor CE can achieve that gain
with narrow band filtering and maintain decently high input impedance.
The catch is you need to have a working knowledge of arithmetic- so that
let's you out.

It had to detect and amplify an 8 kHz VLF
carrier about a buried loop in a parking lot to lock shopping carts
(trolleys in the UK)at the perimeter. We eventually updated the design
but what a great little part the 4007 is. Millions of units later the
product is deployed all over the world saving retailers tens of
millions in lost trolleys and carts.
Click to expand...
Whatever- a piss simple non-engineering kluge that ranks with your LED
equipped disco shoe garbage. Did you also make some of those miracle
cure bracelets, or maybe those TV reception gizmos, or any of that other
total trash...GARBAGE_DEVELOPER is what you should really call yourself.
 
Joerg wrote:
Hi Jim,

Aren't 74xC... parts dirt cheap? And their smaller feature size means
they consume less power for a given toggle speed.



They are dirt cheap but many times the respective CD4000 part is still a
tad cheaper. In consumer products one penny can make all the difference.
Also, CD works up to 15V, sometimes 18V so you can run it off a 12V lead
acid battery or a 9V block without any regulator.
Click to expand...
I recall seeing numerous warnings from manufacturers like National about
not running the 4000 in linear mode above 5V- that 12-15V is definitely
out- the quiescent current may be very high. Why don't you measure it.

Might be interesting to post some CD4000 series circuits (operated at
= 5V) and compare power consumption/performance with modern parts.



I never design with CD4000 under 6V because their performance becomes
very sluggish. That's clearly the 74HC domain. But they don't offer
stuff like a CD4007 in that technology. There would be a market but only
if the mfgs see it and only if the engineering public would be educated
about its many uses.

For really slow stuff like a 4060 timer I could see an operation of
CD4000 logic under 5V, or if you wanted to use them for slow analog
jobs. But not for anything in the MHz range.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
 
Ken Smith wrote...
BTW: There really was a one bitter, the 14500.
Click to expand...
I have a pdf files of Motorola's 6-page mc14500 datasheet, in case
anyone is interested.

This one-bit CMOS processor had 16 instructions, operated at 1MHz,
worked from 3 to 18V supplies, along with the rest of the mc14000
and cd4000 cmos families, and came in a nifty 16-pin DIP package.


--
Thanks,
- Win
 
On Tue, 16 Nov 2004 02:30:24 +0000 (UTC), Ken Smith wrote:

In article <Ywbmd.44507$QJ3.37685@newssvr21.news.prodigy.com>,
Joerg <notthisjoergsch@removethispacbell.net> wrote:
[...]
It was the thermostat he designed. Realtime clock, programmable, LCD,
the whole nine yards except for the remote. With a four-banger in there.

Four bits luxury! We had to do our designs with only one bit and were
happy to have that.

BTW: There really was a one bitter, the 14500.
Click to expand...
I wonder if that's the one that was used in that old Circuit Cellar
supercomputer article - the Mandelbrot Engine.
The company I work for was one of the first to even make a multiprocessor
system. The system had 3 4040s in it. They were over clocked so they
really zipped along at about 2.2MHz.
Click to expand...

--
Best Regards,
Mike
 
On Mon, 15 Nov 2004 17:48:14 -0700, Jim Thompson wrote:

On Mon, 15 Nov 2004 18:58:18 -0500, Active8 <reply2group@ndbbm.net
wrote:

On Mon, 15 Nov 2004 23:17:22 GMT, Joerg wrote:

Hi Active8,

snip

Right. Being the best can go a long way.



Unfortunately that ain't always the ticket. These days companies often
don't go after the best. They look for 'just good enough but cheap'.

Well yeah. I've seen enough of that to disturb me, but if one got
good at the art while working at reduced rates, he could maybe
parlay that experience into a lucrative career.

That's why I'm nudging Jim to talk a bit. He's BTDT :) But I doubt
he got screwed around on chump pay when he started out.

[snip]

I started, just out of MIT, for $6760 per year... in 1962. By 1970 I
was making my age in $K. By 1980 I was making 3x my age, $K. After
that I finally started getting paid what I'm worth ;-)
Click to expand...
If you had to start over today, do you think you could do it again
based on trends you've seen over the years in the market/economic
climate? IOW, are we FUBAR?

--
Best Regards,
Mike
 
Rich Grise wrote...
Winfield Hill wrote:

Ken Smith wrote...

BTW: There really was a one bitter, the 14500.

I have a pdf files of Motorola's 6-page mc14500 datasheet, in case
anyone is interested.

This one-bit CMOS processor had 16 instructions, operated at 1MHz,
worked from 3 to 18V supplies, along with the rest of the mc14000
and cd4000 cmos families, and came in a nifty 16-pin DIP package.

I'd be happy to see it on, for example, a.b.s.e.
Click to expand...
Done.


--
Thanks,
- Win
 
On 16 Nov 2004 04:08:23 -0800, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

I'd be happy to see it on, for example, a.b.s.e.

Done.
Click to expand...
For those interested in the link, its:
Message-ID: <cncqip0319u@drn.newsguy.com>

Jon
 
On Tue, 16 Nov 2004 17:49:32 +0000, Jonathan Kirwan wrote:

On 16 Nov 2004 04:08:23 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

I'd be happy to see it on, for example, a.b.s.e.

Done.

For those interested in the link, its:
Message-ID: <cncqip0319u@drn.newsguy.com

Thanks, and >> Thanks. :)
Click to expand...
Rich
 
Hello Steve,

There are also a few diodes. I'm sure with a little more work
conducting semiconductor junctions could be dispensed with entirely,
except maybe one zener !
Click to expand...
Since the 5V doesn't need to be too accurate you could use a CMOS device
as a regulator if your 7.5V is predictable enough. A voltage divider may
be sufficient to provide a "reference". The drop would be 2.5V so you
might be far enough away from midpoint for low enough cross current.
74HC can take up to 6V. Just an idea towards your goal to do an
all-CMOS logic design without even a diode.

Be careful with low drop-out regulators. Many of them tend to become
unstable when the battery impedance goes up.

Regards, Joerg

http://www.analogconsultants.com
 
"Steve Kavanagh" <skavanagh72nospam@yahoo.ca> wrote in message
news:5249fb3f.0411160645.4b50ede0@posting.google.com...
Thanks for the suggestions (Joerg, too).

bigcat@meeow.co.uk (N. Thornton) wrote in message
news:<a7076635.0411151843.3fa6d3a7@posting.google.com>...
Click to expand...

[clip]
An inverter operating in linear mode has truly awful
audio-frequency noise figure at 50 ohms source impedance. I don't
know what the number is but it is certainly huge.
[clip]

Steve
Click to expand...
Yes indeed.
ISTR the fets in a 4007 give about 0.2uV per rootHz. Makes 'em a bit of a
problem for use with audio input below say 1mV.
 
Rich Grise wrote:
There was a chip out once, the 8X300, that was designed and touted
for nothing but speed
Click to expand...
I still have the Signetics databook for this part :).
 
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