I've come across with some datasheets which warn you by saying: Not recommended for new designs. What does that mean? What is behind that?

 

I've come across with some datasheets which warn you by saying: Not recommended for new designs. What does that mean? What is behind that?

It means just what it says. Not recommended for new designs. This is usually done when the part is no longer available, will shortly become unavailable, or a superior part is now available.

 

It means just what it says. Not recommended for new designs. This is usually done when the part is no longer available, will shortly become unavailable, or a superior part is now available.

There is a fairly protracted process for informing manufacturers that depend on chip availability what the plans are. "Not Recommended for New Designs" is one of the first steps in getting the word out. Specifically it means that in the not too distant future will come an EOL (End of Life) Announcement. This announcement will specify a date on which the final orders will be taken, and a date on which final deliveries of orders will be fulfilled. If there are still chips left in inventory they may end up on the grey market where price and availability are 'sketchy' to say the least.

As an experimenter you can use these chips for learning or one off experimentation, but don't design them into a product you plan to make hundreds or thousands of.

 

I've come across with some datasheets which warn you by saying: Not recommended for new designs. What does that mean? What is behind that?

In a word; "obsolescent" - you can still buy them while stocks last, but the production line is finished.

There's not actually that many silicon foundries and a standard part can turn up with all sorts of brand names on it. There may be other places to look.

 

Not recommended for new designs. What does that mean? What is behind that?

Also it does not necessarily mean there is something wrong with the chip, just that later versions may have some superior options or characteristics, and this version is discontinued, if you have a couple or more and can still make use of them then go ahead.
Max.

 

It is a little different for Microchip, PICs at least. So far, Microchip doesn't obsolete parts but they do get more expensive AND development tools may no longer be available. For example, you can still buy the original PIC16C54 - for about the same price as a PIC32 or big 18F. Not such a great deal. But the good news is that if you have a product that uses it and you don't have any way to upgrade to a newer part, you can still buy it and stay afloat.

Microchip will offer alternative part numbers when you pull up the product page of a Not Recommended.. chip, 16F54 for example. They were also smart enough to package a lot of the newer architectures like the Enhanced Midrange in pin-compatible packages. That's a bit more work but it is nice to know that you can get a big upgrade for your socket for pretty cheap. That 18 pin 16C54 or 16F84 socket will take a 16F1826 which is way cheaper and way better with really good development tools.

So when you see the Not Recommended For New Designs, in Microchip at least, drill down and get the latest and greatest.

Just my .02

 

I am very grateful that the manufacturers still provide the data sheets in the manuals, because when repairing equipment the data on the devices can be very important.
In designing equipment that is intended to last for many years it is VERY important to use components that will be available for the anticipated lifetime of the equipment. Often production machines will be required to perform perfectly for up to 20 years, and so all of the components must remain available.

 

It is a little different for Microchip, PICs at least. So far, Microchip doesn't obsolete parts but they do get more expensive AND development tools may no longer be available. For example, you can still buy the original PIC16C54 - for about the same price as a PIC32 or big 18F.
...
Just my .02

Be happy that production equipment dinosaurs still exist but one day a comet called replacement parts will make extinct scaly creatures incompatible with modern life.

 

Nicely put given that I am pretty much already incompatible with modern life.

 

Be happy that production equipment dinosaurs still exist but one day a comet called replacement parts will make extinct scaly creatures incompatible with modern life.

Not every manufacturer is striving to follow the latest fads in products, in spite of the fact that so many marketing plans depend on a product being completely obsolete in 6 months and failing to function after 8 months. The capital investment in production equipment is great enough that it has to last longer than a year. And that whole concept of products all being custom produced chooses to ignore the reality that the logistics of placing orders and receiving product can never be instant, and so the whole idea, which is built on instant gratification of whims, is not likely to be a big part of anything beyond food delivery in eating establishments. Even today, while you can special order at a fast food joint, it always takes longer than ordering the standard fare. That will probably exist even in those robotic food shops that are starting to appear.

 

I know a fellow who designs, manufactures,and sells FM transmitters in low quantities. He has no qualms about using discontinued parts if they are superior to others as long as there is plenty of old new stock "out there".

If you are going to build just a few of something it is easy enough to buy enough for the planned build plus spares.

 

Not every manufacturer is striving to follow the latest fads in products, in spite of the fact that so many marketing plans depend on a product being completely obsolete in 6 months and failing to function after 8 months. The capital investment in production equipment is great enough that it has to last longer than a year.

In the general case with no specifics we are not talking about a few years on production equipment. The time frames is decades of 7/24 operation to the point that the original opto-isolator leds have dimmed to the point of intermittent operation, plastic hoses have dry rotted and even the best roller bearing have turned to dust in perfectly controlled dustless conditions.

http://www.ftsplasma.com/blog/2015/12/20/trends-in-semiconductor-manufacturing-process-equipment

Many 150 and 200 mm wafer fabs are using equipment that is 20 years old, or more. Devices being manufactured on these tools were not even conceived when these process tools were developed, and it was always thought that the lifetime of the tools would be on the order of ten years.

While many factories have changed owners and many others have closed, the factories running these older toolsets tend to be at capacity. The equipment, while it may have been resold and often rebuilt in the process, is still being used to perform in many cases much more difficult tasks then when designed. But the use of fully depreciated equipment allows production at costs far below newer 300 mm factories, even if they are not capable of the smaller geometries that the 300 mm tools can run.
...
In summary, the bulk of semiconductor manufacturing is done using older equipment, maintained by a combination of OEM and aftermarket companies, and this equipment has been pushed far beyond its expected lifetime. The inventiveness required to keep this equipment able to maintain processing integrity with good uptime is immense, and results vary a lot across the industry. It is largely to the credit of wafer fab staffs and small support companies comprised of ex-fab and ex-OEM equipment technicians that this industry is able to run as well as it does in the face of ever-increasing demands.

There is a limit to this immense engineering effort.

 

There is never any certainty of supply of any component. You can design in a part, feeling confident because a distributor has a hundred thousand pieces on the shelf, only to discover a week later that the stock is all gone and the lead time is 26 weeks, or 52 weeks, or you've been sent a notice that manufacturer has quit making the part.

There are parts, like the 741 op amp, that really should have be obsoleted a couple of decades ago. It was a good op amp in its day, well back in the last millennium, but it just doesn't stack up well against a vast array of newer designs. But it persists. I'm amazed at how many AAC members are trying to use it. At least the revised datasheets no longer refer to it as "high performance."

 

Be happy that production equipment dinosaurs still exist but one day a comet called replacement parts will make extinct scaly creatures incompatible with modern life.

I have a customer that was using a sub-assembly from a Japanese manufacturer. With short warning, they received a notice that the product was no longer going to be produced. At the time, I assumed that this old thru-hole product was no longer profitable to make.

Later, I found out that Molex-Japan had discontinued some of the connectors used on the sub-assembly. Their explanation was that tooling was damaged and would not be rebuilt. I suspect that the tooling was damaged in the 2011 tsunami that hit Japan and caused the Fukushima disaster.

 

More reasons for discontinued notice:
1. Process is being dropped; cannot make more.
2. Process is being dropped but IC is being moved to another process. IC may meet data sheet parameters but not work in your design.
3. Can't control parameters.
4. Generally a new device is available with reduced function or increased price.
5. Will not test to the specified parameters.

 

A big part of my career was indeed designing production equipment that would run 24/7, or more typically, 20/6. So everything had to keep working. For custom electronics assemblies my choice was to use components available from multiple vendors so that a disaster for one would not create a disaster for my products. And I understood those warnings very well,
In a fairly recent meeting at an auto company, there was a question about service parts being available for a product of mine, since it was already ten years old. I was able to point out that all of the electrical items were still available from DigiKey and Newark, as well as other suppliers, and so if the things ever required service parts, those were easily available. I also explained that this was intentional for that very reason.