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| Did I buy fake Linear Tech. ICs? |
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| thm_w:
--- Quote from: qat on February 03, 2022, 11:22:21 pm ---You managed to find the exact two sellers I purchased from. ;D I have other new parts (directly from Linear) that have test marks too. Like you say it would be very impressive if they were tested by the seller... I think it's more likely they had a look at a new genuine part and hired someone with a needle to put dents in all the salvaged parts to make them look more legit. --- End quote --- At least we know that first seller is using real photos, of the ICs they have in stock. So, if the photo is of the actual part, you might be able to tell if its genuine or not, if it has the dots. The second seller appears to be using generic photos, not of the part they ship out (easier to file a claim if it doesn't work?). One other thing, the pads of the left side part are larger than the right side part. Does any other IC use this oddball package? Or other vendors? --- Quote from: Algoma on February 03, 2022, 11:47:34 pm ---Those vendors do list quite a few for sale, with that many, its more likely to be surplus from a production run. Date codes are more likely New (OLD) stock found sitting in a warehouse. --- End quote --- You can't necessarily trust those numbers, maybe if it said "58 pieces in stock" I would trust it, but if it says "9999", who knows. But yeah, you are probably right. |
| qat:
--- Quote from: thm_w on February 04, 2022, 01:55:17 am --- --- Quote from: qat on February 03, 2022, 11:22:21 pm ---You managed to find the exact two sellers I purchased from. ;D I have other new parts (directly from Linear) that have test marks too. Like you say it would be very impressive if they were tested by the seller... I think it's more likely they had a look at a new genuine part and hired someone with a needle to put dents in all the salvaged parts to make them look more legit. --- End quote --- At least we know that first seller is using real photos, of the ICs they have in stock. So, if the photo is of the actual part, you might be able to tell if its genuine or not, if it has the dots. The second seller appears to be using generic photos, not of the part they ship out (easier to file a claim if it doesn't work?). One other thing, the pads of the left side part are larger than the right side part. Does any other IC use this oddball package? Or other vendors? --- Quote from: Algoma on February 03, 2022, 11:47:34 pm ---Those vendors do list quite a few for sale, with that many, its more likely to be surplus from a production run. Date codes are more likely New (OLD) stock found sitting in a warehouse. --- End quote --- You can't necessarily trust those numbers, maybe if it said "58 pieces in stock" I would trust it, but if it says "9999", who knows. But yeah, you are probably right. --- End quote --- The first seller is the one who sent me the parts with white text. The second one seems to have copied the photos from here: https://jlcpcb.com/parts/componentSearch?isSearch=true&searchTxt=lt3797 and removed the watermark. What's also worth noting is that the first seller sent me parts in a sealed antistatic bag with printed labels, and the second in a normal clear ziplock with sharpie on it. I also noticed the difference in pad size, at first I thought maybe if one was ground down that'd explain it but that's something I'm starting to find harder and harder top believe. I have yet to find any other component with this package. |
| qat:
What's also interesing is that Linear themselves have two variations of the UKG package. The IUKG and EUKG. In the datasheet it says they are different sizes - 7x8mm vs 7x7mm. However the datasheet only has one drawing for the UKG package, and everywhere else they appear to be the exact same package. In Linear's own database they have material declarations for both; and at the top of both documents it says "QFN 7mm X 8mm Exp. Pad" on both. EUKG: https://www.analog.com/media/en/material-declaration/LT3797EUKG%23PBF.PDF IUKG: https://www.analog.com/media/en/material-declaration/LT3797IUKG%23PBF.PDF Maybe the case here is that I got send one set of IUKGs and one set of EUKGs (which have the same physical markings)? I'm going to send Analog/Linear a message about this discrepancy and report back if they respond. |
| tom66:
I think it's more likely the 7 x 8mm is a typo. ST Micro is notorious for their typos and weird sayings in the datasheet (I joke at work that they write the documents in English, translate them into French, then back into English) |
| qat:
--- Quote from: tom66 on February 04, 2022, 11:43:02 am ---I think it's more likely the 7 x 8mm is a typo. ST Micro is notorious for their typos and weird sayings in the datasheet (I joke at work that they write the documents in English, translate them into French, then back into English) --- End quote --- I think it’s more likely the 7x7mm is a typo in this case which would make sense. By why two different packages that are identical both dimensionally and in material composition? |
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