Fake TL082 are actually a cheaper model (?)

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
hi, i bought on ebay china some TL082CP apparently made by Ti... the actual problem is that i'm not sure these are real TL082, i suppose they are LM358 or something REALLY cheap

why?
because i've found some behavoiurs that really belong to LM358 and not TL082, for example::
- 1 mA of consuption for entire package (seems low)
- 8 nA (calculated) coming out of the + input if arranged as voltage follower (it slowly charged a 10uF cap already taken at 5V and i measured the "rise time" on a known cap)
- crossover distortion (i don't remember very well but it was pretty visible on a 2k (?) load)
- ability to output down to GND

my questions are::
am i crazy or there really is some possiblities that these are counterfeits? (again... china)
is there some bombproof test for knowing if these markings are "sincere"?

the upper code is the same for all chips and
i don't think this is a good foam for JFET devices


 

dl324

Joined Mar 30, 2015
9,154
am i crazy or there really is some possiblities that these are counterfeits? (again... china)
No. The extremes that they'll go to are surprising. They'll pull SMT caps from salvage electronics and resell. But most caps aren't labeled with value, so caveat emptor...
is there some bombproof test for knowing if these markings are "sincere"?
The logo doesn't look authentic, and parts appear to be black topped. Check the bottom of the package to see if it matches the texture and color of the top; it should. The tops of the leads also look like they've been sandblasted (which is done before applying the black top).

Some manufacturers have remarked parts on occasion, but it's the exception.

It's anyone's guess what you bought. They often just match package type without regard to what's actually in it. Might be LM358, might not. In any case, they're counterfeit.

I stopped buying parts on eBay many years ago. Anyone who routinely stocks the same parts may be selling counterfeits and not know it. If it's someone who sells an odd lot here and there, they might be authentic.

Buy from reputable resellers that have a reputation to protect (Newark, Mouser, Digikey, Jameco, etc). I'd also avoid Amazon.
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
wow.. thanks for the answer... that's also a big downer... well, the sandblaster thing on pins appears to be the same of other genuine NOS parts i have (exactly the same finish), maybe the pic is a bit "deviant"... the bottom has the same surface and shade of the top and the package bottom "print" seems more sheer inside (probably some proof of not beeing sandblasted (at least on the bottom))

that's the "best" decapping i can do LOL... however the die seems pretty wide but thin
...i also can make some aimed tests (got scope... and a blow torch :cool:)


 

dl324

Joined Mar 30, 2015
9,154
the sandblaster thing on pins appears to be the same of other genuine NOS parts i have (exactly the same finish),
Any parts that appear to have been sandblasted are likely counterfeit.

Where did you acquire the "genuine NOS" parts?

From what I can see in the pictures, the bottom of the package looks like it has a different texture than the top. That's a dead giveaway that the part was remarked.
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
well, i'm not "selling tales" (i hope), i bought the parts from a town seller something like 17 years ago... the guy had them on the shelf wAAAAy before the dinosaurs asteroid LOL.... are you telling me that this "path" is vicious?... i also have some 555 and a couple of 082 but... yes, they have polished tin surface on the pins

btw the camera isn't that reliable about color and shade, especially at that magnification


 

dl324

Joined Mar 30, 2015
9,154
i bought the parts from a town seller something like 17 years ago... the guy had them on the shelf wAAAAy before the dinosaurs asteroid LOL.... are you telling me that this "path" is vicious?...
Counterfeiting wasn't as rampant back then as it is now, but still not possible to rule out completely.
i also have some 555 and a couple of 082 but... yes, they have polished tin surface on the pins
Sandblasted pins are atypical. The lead frames are stamped out of sheets of some base metal like brass and then plated; used to be with tin before RoHS. Don't know what they use now. But the plating should be smooth. Shiney can be okay, textured is suspicious.

The epoxy for the package should have the same texture on top and bottom. If the mold marks on the top aren't sharp, that's another clue to tampering.

The markings on newer parts are laser etched, so can't be removed without sanding or sandblasting. That's why we look for black topping and uneven mold marks without clearly defined edges.

The manufacturer logos usually look funny, device lettering may look like it was done by a child (uneven letters, multiple fonts, etc).
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
i think i've solved the enigma... it required a lot of effort... i mean just typing 18MDSHY (the upper code) on google and voilà, just two topics and one of the two is this one https://www.muffwiggler.com/forum/viewtopic.php?t=179427
(i'm not blaming anyone, it was my "mission" since the start)
apparently the problem are the bias currents, so these chips are like driving a ferrari with a beetle engine

- MSGEQ7... check
(worked one out of 3)

- DS1307 (both DIP and SMT)... check
(precise exactly like an hourglass)

- LM35... check
(are actually LM335)

- TL082 (i suppose also 084, 072, 074)...................................................................................... check

i'm posting a topic about the " "LM35" " just for other people to know
 

GopherT

Joined Nov 23, 2012
8,012
i think i've solved the enigma... it required a lot of effort... i mean just typing 18MDSHY (the upper code) on google and voilà, just two topics and one of the two is this one https://www.muffwiggler.com/forum/viewtopic.php?t=179427
(i'm not blaming anyone, it was my "mission" since the start)
apparently the problem are the bias currents, so these chips are like driving a ferrari with a beetle engine

- MSGEQ7... check
(worked one out of 3)

- DS1307 (both DIP and SMT)... check
(precise exactly like an hourglass)

- LM35... check
(are actually LM335)

- TL082 (i suppose also 084, 072, 074)...................................................................................... check

i'm posting a topic about the " "LM35" " just for other people to know

What supply voltage are you using on the TL082?

And, to answer your question in the Title, is there a cheaper Op Amp than the TL082? I think you can get them in bulk for $0.35 each.
 

DickCappels

Joined Aug 21, 2008
5,950
What supply voltage are you using on the TL082?

And, to answer your question in the Title, is there a cheaper Op Amp than the TL082? I think you can get them in bulk for $0.35 each.
TJM4558CDT
Dual Bipolar Op-Amp,Gain Bandwidth 5.5MHz
Manufacturer: ST MICROELECTRONICS
Slew Rate 2.2V/us,Input Offset Voltage 1mV

About 6¢ is you only buy one, cheaper in higher volume. LM324 about 7¢.

http://www.es.co.th/detail.asp?Prod=023500721
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
What supply voltage are you using on the TL082?
12V single supply... another genuine TL082 draws 4mA at this voltage (way more realistic), the datasheet states that the current consuption doesn't vary much even from 8V
And, to answer your question in the Title, is there a cheaper Op Amp than the TL082?
apparently the barely true answer "yes" is enough for faking em LOL
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
the saga continues...
here are some fake NE5532 (NE5532P) marked "72AGRYM" that draw the same 0.5-1mA instead of 8mA and dont show the protection transistors at the inputs

btw... i don't think that these are remarked but just bottom end ICs that at some point were printed with a more "interesting" code during manufacture


 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
Most have no problem outing crooks.
yeah.. that's the funny fact.. who can ensure me that paying more means getting good stuff?

the only 100% secure way for me to have original ICs is to buy em from top ranked\specialized sellers out of ebay or amazon... this also means not having "factory prices"... i've bought something like hundreds of items on ebay and i had problems with just the ones i mentioned in this thread
 

GopherT

Joined Nov 23, 2012
8,012
yeah.. that's the funny fact.. who can ensure me that paying more means getting good stuff?

the only 100% secure way for me to have original ICs is to buy em from top ranked\specialized sellers out of ebay or amazon... this also means not having "factory prices"... i've bought something like hundreds of items on ebay and i had problems with just the ones i mentioned in this thread

You must be buying in very high volume that a 10 cent IC makes a big savings vs paying 25 cents from a top ranked distributor like Digikey.
 

dl324

Joined Mar 30, 2015
9,154
who can ensure me that paying more means getting good stuff?
My orders from Newark and Jameco come with letters signed by the CEO attesting to the authenticity of the parts.
the only 100% secure way for me to have original ICs is to buy em from top ranked\specialized sellers out of ebay or amazon... this also means not having "factory prices"... i've bought something like hundreds of items on ebay and i had problems with just the ones i mentioned in this thread
You're playing ostrich. You just haven't noticed any problems. Even counterfeiters will throw in a few known good parts, so you have to do 100% incoming testing to insure parts are up to specs.

I wouldn't trust any "ranking" on eBay or Amazon. It's most likely as fake as the products they sell.

You should expect to pay a reasonable price for electronic components. If you're getting them super cheap, they're either counterfeit, trash, or stolen.

I learned a valuable lesson from AliExpress. I bought some 64GB microSD cards that I thought were coming from a SanDisk manufacturer in China who had decided to compete with their customer. It turns out they were just counterfeits. 8GB parts relabeled to look like SanDisk (without the name) that were hacked to report size as 64GB.
 

Thread Starter

BulbChangeExpert

Joined Mar 26, 2016
54
You must be buying in very high volume that a 10 cent IC makes a big savings vs paying 25 cents from a top ranked distributor like Digikey.
i honestly don't know how much is it shipped to italy... i payed for 50 NE5532 "just" 1.5€ shipped... btw i also order stuff randomly so a post service (in terms of price) would be better (i think)
just enlight me:)

You should expect to pay a reasonable price for electronic components.
yeah... that's why i buy em at factory prices for a lifetime lasting stock... i can make a trip to the nearest city and buy general purpose ICs wich are SUPPOSEDLY genuine but a TL082 costs me 1€... a misconnection and it's "puf"
 
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