Author Topic: Warning: Fake LM2937 are on the market without reverse polarity protection.  (Read 884 times)

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Offline Psi

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As the topic says,
Just a warning that fake LM2937 regulators are out there.
They don't include the reverse polarity protection, any reverse polarity causes them to explode.
I expect they also don't include the 60V transient protection too, but this is harder to test. 
They are likely just some other random regulator stamped to look like a LM2937 since the LM2937 is quite expensive due to automotive rating.

I just found out because a unit from the latest batch of products blew up on me.
The PCBA BOM had in big bold red letters that this part is critical and must be genuine.

I might post a video of genuine vs fake chip exploding from reverse polarity later.
The PCB was populated at a popular PCB assembly house that we all know. I'm still deciding if i will name them and am waiting to hear back from my email.

But yeah, if you sell a product that uses the LM2937 regulator and don't do a reverse polarity test as part of production processes you should start doing it and check existing products.
It's an easy thing to miss as the product will works fine otherwise. Except maybe being more prone to random failures without the 60V transient protection.


« Last Edit: February 17, 2019, 02:28:34 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline CJay

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Ouch, any pics of the fakes?
 

Offline Refrigerator

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I might post a video of genuine vs fake chip exploding from reverse polarity later.

Please do.
Just started a blog at http://brimmingideas.blogspot.com/ . Not much in it as of now but more is sure to come :)
 

Offline Psi

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Greek letter 'Psi' (not Pounds per Square Inch)
 
The following users thanked this post: thm_w, edavid

Offline Bassman59

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Please post the name of that assembly house.
 

Online wraper

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Yep, post the name. Regardless if they handle this situation well, it will be just the same as with Chinese ebay sellers. They'll fix it for you and will happily continue to use/sell fake crap for others.
 

Offline schmitt trigger

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Your video should be done in your best Hindenburg disaster narrator's voice:

It's smoke, and it's in flames now; and the component is releasing its magic smoke, not quite to the center of the body. Oh, the humanity! And all the technicians in the lab screaming around here.
« Last Edit: March 04, 2019, 07:11:54 pm by schmitt trigger »
 


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