Since the OPA627 is prone to being a counterfeit when bought through alternative channels, I was wondering if it would be helpful to you guys if I were to maintain a list of datecodes of genuine OPA627s I come across at work from now on.
After having been confronted in the past with counterfeit OPA627s, the company I work for nowadays only orders them from a reliable (authorized) supplier. That fact together with successful tests on the instruments they're used in make it fairly certain that they are the real deal.
We use the following versions:
OPA627AP (plastic DIP);
OPA627AM (TO-99 metal);
OPA627BP (plastic DIP);
OPA627AU (SOIC).
Most of them will be the BP followed by the AU and occasionally the AM and AP versions.
We're talking of 1000-2000 OPA627s a year, bought in smaller batches, so we get to use quite some different datecodes. It's little effort for me to post them here, if you're interested.
After having been confronted in the past with counterfeit OPA627s, the company I work for nowadays only orders them from a reliable (authorized) supplier. That fact together with successful tests on the instruments they're used in make it fairly certain that they are the real deal.
We use the following versions:
OPA627AP (plastic DIP);
OPA627AM (TO-99 metal);
OPA627BP (plastic DIP);
OPA627AU (SOIC).
Most of them will be the BP followed by the AU and occasionally the AM and AP versions.
We're talking of 1000-2000 OPA627s a year, bought in smaller batches, so we get to use quite some different datecodes. It's little effort for me to post them here, if you're interested.
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Those are things I'm aware of and are the reasons why I didn't just start posting the LTCs without asking first.
I agree that the LTC in itself doesn't give a definitive answer. It must be combined with a careful examination of features and, if possible, some technical specs.
I know that one of the counterfeit batches of the OPA627BP we received all had the same datecode. Comparing the bottom side of some ICs immediately made us suspicious: in the circle on the bottom it should say THAILAND, instead some just had two digits in them, others said TAIWAN or MALAY.
Another incredibly simple test revealed they were fake: current draw from the PSU wasn't anywhere near the 7 mA it should be!
I agree that the LTC in itself doesn't give a definitive answer. It must be combined with a careful examination of features and, if possible, some technical specs.
I know that one of the counterfeit batches of the OPA627BP we received all had the same datecode. Comparing the bottom side of some ICs immediately made us suspicious: in the circle on the bottom it should say THAILAND, instead some just had two digits in them, others said TAIWAN or MALAY.
Another incredibly simple test revealed they were fake: current draw from the PSU wasn't anywhere near the 7 mA it should be!
Country of origin is not a sure-fire indicator. Before becoming part of TI, Burr-Brown did assembly/test of plastic parts in subcons in Singapore and Malaysia. Their 'date code' scheme was different than TI's. Now that TI owns them, the parts can still be built at one or more subcons (various countries) and/or TI factories (Malaysia, Taiwan, most likely). If you are dealing with only recent vintages, consistency of visual appearance with known-good material is a good start. Checking very basic specs, such as quiescent current is also very good - you shouldn't expect anything outside the datasheet specs.
Yes, they can come from different factories in different countries, but in the case of the counterfeit batch all ICs had the same datecode/LTC on top yet several different countries of origin in the circle on the bottom. That tipped it off in this case.
Since we keep as little stock as possible, we're mostly dealing with recent vintages. Recently produced pcbs have OPA627BPs from January and March of this year. I will post some pictures of old (ca. 2000), young (ca. 2009) and recently produced OPA627AP/BPs just to show how the appearance has changed over the years.
At the time, the counterfeit batches came from what we, and our customer, thought was a reputable distributor.
Informing them and TI/BB was a waste of time. TI/BB is aware of the counterfeiting problem, and the most helpful comment we got from them was "to buy from reputable distributors only". The only ramafication for the distributor was that we don't buy parts from them anymore.
Nowadays we buy the OPA627 from a big and well known globally operating distributor only. A good choice as they probably deal with TI/BB directly and not through a third party.
Informing them and TI/BB was a waste of time. TI/BB is aware of the counterfeiting problem, and the most helpful comment we got from them was "to buy from reputable distributors only". The only ramafication for the distributor was that we don't buy parts from them anymore.
Nowadays we buy the OPA627 from a big and well known globally operating distributor only. A good choice as they probably deal with TI/BB directly and not through a third party.
And now for some photographs of genuine OPA627APs from several vintages.
The first picture is a OPA627AP mounted on a board we use as a reference ("golden board"). This board was assembled in 2000 and the IC itself is presumably from 1999 week 31.
The second picture is from another golden board assembled in 2006. The LTC-scheme has changed to what is looks like nowadays and is probably the result of TI taking over BB. IC from 2006 month 4.
The last two pictures are from current production in Thailand. The one on the left is what the OPA627 on the left (2008 month 3) looked like until 2009. Since then, they look like the one on the right (2011 month 1). This also goes for the OPA627BP.
Buying online from eBay or other unconfirmed sources is risky with these expensive and therefore counterfeit prone components. Even if you have an opamp that looks similar to one of the pictures, that is no guarantee it is.
I posted these not only as a guideline what to look for but also as a warning not to judge genuineness by looks alone because, as you can see, looks change over time.
The first picture is a OPA627AP mounted on a board we use as a reference ("golden board"). This board was assembled in 2000 and the IC itself is presumably from 1999 week 31.
The second picture is from another golden board assembled in 2006. The LTC-scheme has changed to what is looks like nowadays and is probably the result of TI taking over BB. IC from 2006 month 4.
The last two pictures are from current production in Thailand. The one on the left is what the OPA627 on the left (2008 month 3) looked like until 2009. Since then, they look like the one on the right (2011 month 1). This also goes for the OPA627BP.
Buying online from eBay or other unconfirmed sources is risky with these expensive and therefore counterfeit prone components. Even if you have an opamp that looks similar to one of the pictures, that is no guarantee it is.
I posted these not only as a guideline what to look for but also as a warning not to judge genuineness by looks alone because, as you can see, looks change over time.
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I think the buzzword you're looking for is "authorized distributor." The TI website should have a list of authorized distributors, and if the distributor in question (from which you got counterfeit parts) IS on that list, I'd think TI would want to know. If the distributor is NOT listed by TI as an authorized distributor (which is what it sounds like TI was saying), you might as well be buying off ebay.
You're right, "authorized" is the keyword here.
The fake batch was not from an authorized distributor. Nowadays we buy them exclusively from Arrow and/or Avnet, both are listed in TI's HiRel Authorized Distributors list.
Here is a picture of a OPA627AU and soon I'll complete this thread with some OPA627AMs, a version we've also had a counterfeit batch from.
The fake batch was not from an authorized distributor. Nowadays we buy them exclusively from Arrow and/or Avnet, both are listed in TI's HiRel Authorized Distributors list.
Here is a picture of a OPA627AU and soon I'll complete this thread with some OPA627AMs, a version we've also had a counterfeit batch from.
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I happen to be in Hong Kong this week and was in Shenzhen for some surveying of the electronics scene. I got in contact with a couple of people that sold OPA627s over eBay and visited their kiosks. It was interesting to hear what they had to say.
The reason i picked them was that having bought enough of their parts and non-rigorously tested them electrically and listened to them, felt enough confidence in the quality level. They both told me their was one seller on eBay that sells OPA627 on eBay at low price. Their chips, according to them, were not even labelled with the right suffix (I think they said SM) and this outfit did a good volume over eBay.
On the bright side (to be verified), I bought a bunch of 627HAs, 627BPs and sundry chips from him. Hopefully if somehow they test good maybe I have a more trusted source for these parts.
The reason i picked them was that having bought enough of their parts and non-rigorously tested them electrically and listened to them, felt enough confidence in the quality level. They both told me their was one seller on eBay that sells OPA627 on eBay at low price. Their chips, according to them, were not even labelled with the right suffix (I think they said SM) and this outfit did a good volume over eBay.
On the bright side (to be verified), I bought a bunch of 627HAs, 627BPs and sundry chips from him. Hopefully if somehow they test good maybe I have a more trusted source for these parts.
As promised some pictures of some other versions of the OPA627.
Here's a picture of the OPA627BP, the version we use the most. They look just like the AP version, but I chose to post this one anyway as it's of a lot that wasn't marked straight. These are genuine. I guess the tool for etching the brand and type on top was worn out because not that much later the marking changed to what it looks like nowadays (see post #8, datecode 11WJFRB). Datecode marking was not changed.
This particular IC is from November 2008.
Here's a picture of the OPA627BP, the version we use the most. They look just like the AP version, but I chose to post this one anyway as it's of a lot that wasn't marked straight. These are genuine. I guess the tool for etching the brand and type on top was worn out because not that much later the marking changed to what it looks like nowadays (see post #8, datecode 11WJFRB). Datecode marking was not changed.
This particular IC is from November 2008.
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Now for some pictures of several vintages of the AM version.
Since TI/BB changed the status for this version from "Active" to "NRND" (Not Recommended for New Design) availability became an issue. They are still out there, but not always abundantly available. I guess TI/BB nowadays produces them only when demand is sufficient.
Because of this all except one of the products of our customer(s) no longer use the AM version. Despite that, I still have quite a few pictures.
The first two pictures are from a small stock I keep in my desk for repair. They're old, so the first one is probably from 2001 month 3, note that the encircled R is still present.
The second picture shows one from 2006 month 2, the encircled R is not present anymore and the printing on the side is slightly bigger.
A somewhat more recent vintage is in the third picture, this one is from 2008 month 4, etching on top has been replaced by printing.
The fourth picture is from recently bought OPA627AMs. These are from 2011 month 5. Note the change in font of the printing on the side of the metal can. Pcbs equipped with this particular datecode have not yet been tested, but since they come from an authorized distributor I assume they're genuine and won't present any problems.
Note the features of the metal can. They're not very shiny and the radius of the bend of the can is not very sharp. The leads and the pin8-tab are gold plated. Counterfeits probably lack these characteristics, the counterfeit batch we received a few years ago certainly did.
Since TI/BB changed the status for this version from "Active" to "NRND" (Not Recommended for New Design) availability became an issue. They are still out there, but not always abundantly available. I guess TI/BB nowadays produces them only when demand is sufficient.
Because of this all except one of the products of our customer(s) no longer use the AM version. Despite that, I still have quite a few pictures.
The first two pictures are from a small stock I keep in my desk for repair. They're old, so the first one is probably from 2001 month 3, note that the encircled R is still present.
The second picture shows one from 2006 month 2, the encircled R is not present anymore and the printing on the side is slightly bigger.
A somewhat more recent vintage is in the third picture, this one is from 2008 month 4, etching on top has been replaced by printing.
The fourth picture is from recently bought OPA627AMs. These are from 2011 month 5. Note the change in font of the printing on the side of the metal can. Pcbs equipped with this particular datecode have not yet been tested, but since they come from an authorized distributor I assume they're genuine and won't present any problems.
Note the features of the metal can. They're not very shiny and the radius of the bend of the can is not very sharp. The leads and the pin8-tab are gold plated. Counterfeits probably lack these characteristics, the counterfeit batch we received a few years ago certainly did.
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They probably told you they're trustworthy and others are not.
The SM version does exist, however, and it should be a metal can.
An authorized dealer will charge in the region of $19 for the OPA627AP, $27 for the BP, $37 for the AM, $39 for the BM and a staggering $76 for the SM.
Anything much lower than this and they're highly likely fake.
HA's, what are those?
Measure the current flowing from the power supply into the OPA627 with a good ammeter. At the specified +/- 15V @ 25 degrees C ambient, it should be approx. 7 mA (max. 7.5 mA). If it's not this value, then it's not an OPA627.
If it is 7 mA and it looks like one of my pics, chances are it's genuine.
As long as I've been dealing with the OPA627AP/BP, and that's at least five years, they have without fail been from one factory in Thailand. The lot trace code since TI took over BB has been in this format: YMLLLLS.
Y = Year
M = Month (1..9 = Jan..Sep; A..C = Oct..Dec)
LLLL= lot code
S = Site of manufacture.
Each and every genuine OPA627AP/BP I've seen has W as the first letter in the lot code and B in de site code. Just look at the pictures of all AP/BPs I posted (with the exception of the first picture in post #8, that AP was made when BB wasn't owned by TI yet).
This leads me te believe that the factory in Thailand is the only factory in the world that has been producing the OPA627AP/BP for the past five years or longer. Now I'm not 100% sure of this, but after having seen at least 3000 OPA627BPs, I have yet to see another sitecode than "B" on new OPA627AP/BPs.
Most pics of OPA627s on eBay shout "fake" to me. They don't nearly resemble the genuine items. Some look as if they're from the pre-TI-era, but I find it hard to believe there are still that many genuine old ones around.
Then there are the ones that have a TI-style lot trace code. There's way too much variation of the last letter of the datecode/lot trace code. There probably aren't that many factories anymore that produce the AP/BP... (and as I said, I've only ever seen "B" on the genuine items we bought).
Then there are the orientation indents. Some have none, some have the half circle indent in the middle and some the circle near pin one. If they do have the circle, it's flat and dull. The genuine OPA627 not only has the half circle orientation indent, it also has the pin one circle that should look like a satellite dish with a shiny surface. In the picture you can see the fluorescent tubes that light our workplace being reflected in it.
Just a few things to look out for...
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AD have an alternative for the OPA627 and OPA637: ADA4627-1 and ADA4637-1.
The part no. ADA4627-1 obviously hints at being a replacement for the OPA627. Compare the datasheets and you'll find that most specs are indeed very similar and some better. Here's another thing: the ADA4627-1 is roughly half the price of the OPA627AU.
Sadly AD don't make them in DIP8, though.
http://www.analog.com/static/imported-files/data_sheets/ADA4627-1_4637-1.pdf
The part no. ADA4627-1 obviously hints at being a replacement for the OPA627. Compare the datasheets and you'll find that most specs are indeed very similar and some better. Here's another thing: the ADA4627-1 is roughly half the price of the OPA627AU.
Sadly AD don't make them in DIP8, though.
http://www.analog.com/static/imported-files/data_sheets/ADA4627-1_4637-1.pdf
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The cans you can grind off and see what is inside. I am curious as to what they are if you could send a couple of fake cans I can return the favor with some ADI parts of your choice. Yes on the AD4627, though TI-BB has replaced the 627 on a more modern SOI process since the DI fab has or is going to be shut down eventually.
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Unfortunately I can't send you any fake OPA627AMs. The last time we encountered counterfeit OPA627AMs was several years ago and the fakes have probably been sent back or thrown away.
I agree that eventually SMT will replace through hole devices, although that may take a while. Some of the designs of our customers still rely on through hole technology (THT). New designs and most redesigns are done in SMT, but some redesigns actually still use THT.
I agree that eventually SMT will replace through hole devices, although that may take a while. Some of the designs of our customers still rely on through hole technology (THT). New designs and most redesigns are done in SMT, but some redesigns actually still use THT.
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Jitter,
Thanks for the info. I surely will test the 627s electrically as you mentioned but also by listening as well. I had bought some 627 mono to dual units before from the guy and with my EE son switching the op amps for me in a blind test in my modded Marantz CD63, they bettered the LM4652s in more intimacy and wider / deeper sound stage. That gave me the confidence to buy more from him but certainly will excercise healthy skepticism.
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