H8S2676 faulty chips

We use the Hitachi H8S2676 chip in one of our products and a while ago Rene sas told us the chip was going out of production. Someone here forgot to d o a lifetime buy from them in time but we recently did a lifetime buy of se veral thousand from a third party company. In the first production run of over 100 boards, every single one failed the manufacturing test. It seems at least one of the problems is when it tries to access internal memory fro m external memory it gets zeros - or something like that (don't have the ex act details). We suspect the chips are counterfeit or seconds or something .

Has anyone heard of this kind of problem?

Does anyone know a reliable source of H8S2676 chips?

Reply to
xyman8
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Can't be of any help but thanks for sharing the info.

Can you perhaps name the third party company, this might help other people in the future.

I have not been burned yet but I have heard plenty of stories about chips bought not via the large, known distributors. There looks to be quite a busyness living on selling you "whatever you need, we'll just have to imprint the logo on a fitting package".

OTOH we bought some fast HV diodes via ebay twice (not sure if it was the same seller both times), were OK.

Dimiter

====================================================== Dimiter Popoff, TGI

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Dimiter_Popoff

Renesas told us the chip was going out of production. Someone here forgot to do a lifetime buy from them in time but we recently did a lifetime buy o f several thousand from a third party company. In the first production run of over 100 boards, every single one failed the manufacturing test. It se ems at least one of the problems is when it tries to access internal memory from external memory it gets zeros - or something like that (don't have th e exact details). We suspect the chips are counterfeit or seconds or somet hing.

Thanks for the reply. I can't name the company as we're still not exactly sure of what's going on. I would have thought that anyone with the technol ogy to manufacture these kind of chips would have the ability to do it corr ectly but it seems they don't.

Reply to
xyman8

It is possible the chips are genuine but a different variant, destined for a large manufacturer. It is also possible that access to the internal memory is a feature that is turned on by setting a bit not normally accessible.

I presume the company you purchased through is a long time served supplier? Can they not assist and confirm their source is legitimate?

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Mike Perkins 
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Reply to
Mike Perkins

Seems to me that if you are buying from any unproven vendor, you would get samples and verify that they were good before a bulk buy ?. With so much fraudulent stuff coming from places like China, we all need to be more vigilant...

Reply to
Chris

Common practice at dodgy vendors (of lithium batteries in this case, but probably applies to semiconductors too) is to supply small orders from genuine stock, and counterfeits for volume orders. That means the samples work fine, and also means any bad feedback on marketplaces like Alibaba is drowned out by good feedback from small customers.

Theo

Reply to
Theo

Are there are semiconductor manufacturers that could make 6000 or so of these chips if we paid them enough money?

Reply to
xyman8

Theoretically: yes Practically: no

To do it, you'd need the design files from Renesas. That includes any proprietary blobs inserted by the foundry. In practice you'd need to use the same foundry they used, because the design will be targeted to a particular process.

Next you need a packaging plan. You need someone to take your silicon dice, and bond it into a package. That may or may not be the same as the existing package - depends on the capability they have.

Then you need a testing strategy.

It's 'only' half the work of designing a new chip from scratch.

Instead I'd be looking at redesigning the product - that's probably a lot easier.

Theo

Reply to
Theo

Thanks. I'm told that we've been unable to determine where the chips were made. So me people here are speculating that the chips were actually made by Renesas but were rejected during manufacture. Does this seem believable?

In a production run of 100 boards here, all boards failed. We bought 6000 of these chips. I find it hard to believe that Renesas would have as many as 6000 failures or that they would allow these chips to escape their facto ry. The reason I'm interested is that if the chips were made by a non Rene sas company, it's possible they have a solution and secondly, how did they get the design files?

Reply to
xyman8

Maybe you could contact Renesas and offer to pay them to examine some of those chips and see if they are legit.

Reply to
Paul Rubin

Some people here are speculating that the chips were actually made by Renes as but were rejected during manufacture. Does this seem believable?

0 of these chips. I find it hard to believe that Renesas would have as man y as 6000 failures or that they would allow these chips to escape their fac tory. The reason I'm interested is that if the chips were made by a non Re nesas company, it's possible they have a solution and secondly, how did the y get the design files?

Uhhh, design files? They could have beach sand inside for all you know, ri ght? It is not uncommon for counterfeit chips to have totally bogus chips inside the package so they x-ray looking like something is in there.

What happened with the company you bought them from? Have they told you wh ere they got them?

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Reply to
Rick C

Some people here are speculating that the chips were actually made by Ren esas but were rejected during manufacture. Does this seem believable?

000 of these chips. I find it hard to believe that Renesas would have as m any as 6000 failures or that they would allow these chips to escape their f actory. The reason I'm interested is that if the chips were made by a non Renesas company, it's possible they have a solution and secondly, how did t hey get the design files?

right? It is not uncommon for counterfeit chips to have totally bogus chip s inside the package so they x-ray looking like something is in there.

where they got them?

Nope, they don't have beach sand. They're functional to a point. They wer e either made by Renesas or someone with the design files and the equipment to make them. However I guess the chance that they were made by a legitim ate manufacturer must be pretty slim as we wouldn't get 100% failure rate i f they were legitimate.

Reply to
xyman8

Have you swapped a chip from an old, good board into one of your new failing boards? Did it work?

Reply to
Paul Rubin

I wasn't involved in the investigation but the guys who did it are fairly capable and they've established the new chips are only partially functional - but I will check.

Reply to
xyman8

e. Some people here are speculating that the chips were actually made by R enesas but were rejected during manufacture. Does this seem believable?

6000 of these chips. I find it hard to believe that Renesas would have as many as 6000 failures or that they would allow these chips to escape their factory. The reason I'm interested is that if the chips were made by a no n Renesas company, it's possible they have a solution and secondly, how did they get the design files?

, right? It is not uncommon for counterfeit chips to have totally bogus ch ips inside the package so they x-ray looking like something is in there.

u where they got them?

ere either made by Renesas or someone with the design files and the equipme nt to make them. However I guess the chance that they were made by a legit imate manufacturer must be pretty slim as we wouldn't get 100% failure rate if they were legitimate.

What do they do right and what do they do wrong?

If they are largely functional but are failing some small detail it is poss ible these are clone chips, a fresh design, not a literal duplicate of the original device.

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  Rick C. 

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Reply to
Rick C

It's weird: are you saying some illicit chipmaker did an unauthorized redesign of this somewhat obscure and not exactly simple part, in order to sell them under counterfeit labels, and left out functionality? Does that really happen? Now that there is a market for working units of the discontinued chip, could the illicit maker issue an erratum and spin another run? There is at least one possible customer...

Reply to
Paul Rubin

You say "obscure", but no one makes low volume MCUs. Most likely you are b uying a chip that is not so obscure other than perhaps the combination of s peed, package, temperature, etc that you chose. Once they have made a die, they are going to sell it into each part number they can. It might not ev en be a new chip design. It's not impossible to reprogram the microcode on an existing chip to emulate another instruction set. Then they only need to deal with the pin out issues.

There was a serial port to USB converter chip that was cloned by reprogramm ing a different MCU chip. It pretty much worked the same, but not quite. The company making the original chip reverse engineered the clone enough to figure out how to reprogram it again, bricking the cable when used with th eir driver. That didn't set well with Microsoft since they were distributi ng the driver with their software.

I don't know what you have, but it sounds like you don't either. I think y ou need more detail from your tech guys to figure out if you have a clone o r a factory reject. I would say turning a chip over to the factory would b e useful, but they may not be interested in helping since they no longer ma ke that chip.

This is exactly why it's not a great idea to buy parts from third parties w ithout some sort of testing and guarantee. I was going to buy some EOL FPG As that were at a good price at a reputable B list seller. They said they had tested them and would guarantee the purchase price, but my assembly hou se said they wouldn't be responsible for the rework if they were faulty. S o I paid the higher price to get them from Arrow who still has stock more t han five years after EOL.

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  Rick C. 

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Reply to
Rick C

Maybe not even illicit or unauthorized (but you could probably check that). I remember a case with an 68000 processor (I may have mentioned that here before, but it seems apropriate in this topic)

We used a CPU card with a 68000 on it a long time ago. These boards were in a rack, connecting to other cards via an 8-bit bus. This design was in use for many years and boards were equiped with Motorola and TI versions of the 68000 without issues. But then we created a new daughter card for the 8-bit bus. This card worked fine when a cpu card with a Motorola 68000 was used, but failed when a TI 68000 was used.

I think that we can be pretty sure that the TI version was not unauthorized, but I never did check. ;-) So what made the TI versions fail?

I do not remember the exact details, but the cause was in 16-bit access over the 8-bit bus, which depended on two consecutive accesses. The bus control signals were derived from the 68000 bus signals by a PAL. In this PAL, one of the 68000 signals was not included in the generation of the 8-bit bus signals. But due to the timing of the other signals, the timing of the bus signals was correct with the Motorola version of the 68000. With the TI version however, a double access was generated on both 8-bit halves of the 16-bit access, resulting in invalid transfers.

After studying the datasheets, we concluded that both processors generated signals within specification. And the error was in our generation of the 8-bit bus control signals. The design was probably originally tested with the Motorola processor and afterwards only a functional test was performed with the TI version. Which worked because all cards at that time only used 8-bit access.

A simple change in the PAL code fixed this problem and then both Motorola and TI 68000's worked as intended.

So what I am trying to say is that there is a possibility that your new processors are in fact functioning correctly, but that an error /omission in your board causes the difference in functionality. Could be something as simple(?) as changed timing due to a new manufacturing process. Something worth to check, in my opinion.

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Reply to
Stef

I doubt this is a clone - I'd have thought this family was an unlikely target for cloning (they don't seem high margin parts).

But you might be right in that it could be one part of the family remarked as another. For instance, MCU families like the Cypress PSoC are all the same die internally, but with different features enabled by firmware. An unscrupulous supplier could remark the cheap chips as the expensive chips - either without any changes (so you'd only notice if you try and use the third UART, or whatever), or with hacked firmware to enable extra features.

But, as mentioned upthread, it would be worth checking whether there have been any production changes to the genuine chip. It could be the stock you bought was a v1 chip while the manufacturer was selling v2 chips until EOL. They might behave functionally the same, until you deviate slightly into undefined behaviour that differs between the different versions.

Theo

Reply to
Theo

The engineers here think the faulty chips were made by Renesas but rejected during manufacturing. We found short a short term supply and we're going ahead with re-designing the board. Thanks for all the comments.

Reply to
xyman8

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