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Topic: Maxim 7219 - Real and Fake compared (Read 7212 times) previous topic - next topic

Apr 14, 2014, 08:28 am Last Edit: Apr 14, 2014, 08:39 am by edr1924 Reason: 1
I came across some very nice pictures.

It's from a Dutch site so I translated the comments.
LINK: http://www.circuitsonline.net/forum/view/85013/7
Pictures by RobinF. He removed the chip housing with sulphuric acid. OUCH!  :smiley-fat:


Real / Fake Maxim 7219 compared:

UPPER: Real Maxim 7219
LOWER: Ebay Maxim 7219




REAL MAXIM:

This is the circuit inside the upper chip on the first photo.
The layout seems to be the same as on the Maxim Datasheet page 14:


The chip is 2mm x 2mm (0.0078" x 0.0078")


Indeed, this chip seems to be the real one:




FAKE Maxim 7219:
This is a photo of the inside of the lower chip on the first photo:


This chip is 1mm x 1mm (0.0039" x 0.0039"). Seems to be a more modern production technology?
No text on the chip surface, only a scissor like image...



comments from Picaxe thread as pointed out by PaulRB:
http://www.picaxeforum.co.uk/showthread.php?22481-Real-or-fake

Note that:
- the end pins are "half pins" - shown as "full-pins" on the Maxim datasheet
- the two moulding marks on the top
- the lack of a dimple by pin one
- underneath perhaps - two moulding marks with two alphanumerics in each and no extra printing?
- end to end 1.171 inches
- the vertical bar on the top somewhat inboard and full width

JoeN

Yep, mine are the fakers for sure.  Except for the ones I got directly from Maxim, those are just like the "real" photos.  Though, and I must stress this, the "fakes" do work for me.

I also have some SOP "MAX7219s".  Any information in determining if these are real or not?  Typical auction:

http://www.ebay.com/itm/50PCS-MAXIM-MAX7219CWG-MAX7219-SOP-24-LED-Display-Driver-IC-8DIG-24SOIC-/310723512133

Almost certainly fake, I would think.

Thanks for the photos, that was great.

I will never ask you to do anything that I wouldn't do myself.

#2
Apr 15, 2014, 04:13 pm Last Edit: Apr 15, 2014, 04:17 pm by edr1924 Reason: 1

I also have some SOP "MAX7219s".  Any information in determining if these are real or not?  Typical auction:


Hi JoeN, here is some C code to check if your Maxim SOP's are fake or not...

void checkGenuineMaxim()
{
 int myMaximSOIC = 2; // enter amount payed
 if (myMaximSOIC <= 5)
 {
   Serial.print("FAKE!");
 }
 else
 {
 Serial.print("GENUINE...");
 }
}

;););) Sorry, couldn't resist... But I think the program result does hold some truth...
Cheap = fake?

I searched for clear photo's of the Maxim 7219 SOIC package but amazingly, I could not find it?!
strange...

JChristensen

I've used MAX7219s from Tayda and while their appearance fits that of the fakes, they seem to work fine for me.

But recently I bought one of those 8-digit LED display modules on eBay, it had an SOIC MAX7219 on the back of the board. The thing worked, but drew about 300mA. The MAX7219 ran very hot to the touch. The LEDs themselves were OK, I removed them and it hardly changed the current usage. I breadboarded a similar circuit (with the Tayda part) and it uses less than one-tenth of the current.

Don't know if it was the MAX7219 itself or something else wrong with the board, but I demanded my money back. At first the guy wanted to give me a partial refund, saying "as our item is very low price ,it may be not as good as other ones that is more espensive  for this case ,can we partial refund to ease you ?"

Of course his web page said nothing about the product being "not as good" so I got pretty direct with him and he did give me a full refund.

Once every few years I have to buy something on eBay just to remind myself why I shouldn't.

Pedro147

I have used about twenty of these cheapies in Marco's Parola boards and various other scrolling LED projects and they work perfectly. No excessive heat but now that Jack has mentioned the potential for high current consumption I will have a look at that but I think it's all good. Sometimes when I have run my eight board Bigger Parola boards from the USB port only because I forgot to plug in an external power supply  :D  it still ran OK.
http://www.pedroduino.com

As Jack said, you have to buy now and then from Ebay to realize that it's mostly junk...
(for example: cut the cheap chinese breadboard jumper wires and see what's inside, or rather... what's NOT inside...)

I also bought 10 Maxim 7219 chips but out of frustration I finally purchased some real ones.
For my DCF77 radio clock project, I used 8 Maxim chips in a daisy chain for the Common Cathode Displays and 1 Maxim for the Common Anode one.

But I noticed that at random, some displays showed strange characters. Also some LED's lit up very dim when they should be off.
I'm curious to see what happens when I use genuine Maxims when they arrive...

front panel text needs to be corrected but it's still a work in progress.

JChristensen


JoeN

DCF77


Anyone know if there is something equivalent to this in the USA?
I will never ask you to do anything that I wouldn't do myself.

Grumpy_Mike


JChristensen

Still SHM as to how it is that someone with the ability to counterfeit the silicon in an IC, can't manage to do the same with the markings on top, especially the position of the line in this case.

#10
Jun 03, 2014, 07:33 pm Last Edit: Jun 03, 2014, 07:40 pm by edr1924 Reason: 1

DCF77


Anyone know if there is something equivalent to this in the USA?


Thanks Jack, Grumpy_Mike...!

Hi JoeN, yes there is a USA equivalent  :) : http://www.nist.gov/pml/div688/grp40/radioclocks.cfm

on the forum: http://forum.arduino.cc/index.php/topic,14946.0.html

I don't know what kind of receiver you need in the USA but there is a lot of info on similar projects focused on the USA WWVB system.

I DO know that, in Europe, there a many inferior receivers. I was able to purchase a good one and it makes all the difference.

oldskooleffects

The cheapest I've found real Maxim 7219's is actually through Sparkfun. Granted, I'm going off their word in correspondence that they are buying direct from Maxim, but I trust their word more than eBay.

masterleo

How did you do that ? What is the technique used ???
I would love to do it !

How do you call the  technique ?
I have a microscope mabe this is usefull ? and some acetone is needed ?

Pedro147

here is some C code to check if your Maxim SOP's are fake or not...

void checkGenuineMaxim()
{
  int myMaximSOIC = 2; // enter amount payed
  if (myMaximSOIC <= 5)
  {
    Serial.print("FAKE!");
  }
  else
  {
  Serial.print("GENUINE...");
  }
}


This code doesn't compile for me. Does that mean my IDE is fake ?   8)
http://www.pedroduino.com

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