Sonsivri
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
December 06, 2016, 03:03:50 15:03


Login with username, password and session length


Pages: [1]
Print
Author Topic: [Q:] Sourcing authentic components  (Read 1450 times)
0 Members and 1 Guest are viewing this topic.
Faros
Senior Member
****
Offline Offline

Posts: 253

Thank You
-Given: 125
-Receive: 178


« on: November 21, 2013, 10:52:58 22:52 »

I always source components through authorized / trustworthy component providers from the US since I can't afford failures due to faulty components, I have a project that requires a switching regulator, I have chosen the TI  LM2596S-ADJ  priced at 1.88$ Qty. 1K.  . To my surprise, there are several Chinese sites links for the same part number priced at 0.1$ , the Qty is not an issue , he can ship 100 pc’s!!! the component list is long and diverged .

Do some members here have experience with such chips? how fake they are?  Give idea on its performance ?
Does anyone have a clue how on earth can the Chinese sell at such price tag? …     
Logged
reksbg
Junior Member
**
Offline Offline

Posts: 49

Thank You
-Given: 22
-Receive: 45


« Reply #1 on: November 21, 2013, 11:51:00 23:51 »

Probably they are not fake just didn't go through QA inspection. We got burnt few times with chips like that. For example MOS transistor from Infineon - it was original even the mask was original but the part didn't pass QA inspection and didn't have good switching parameters. Let's say the chinese manufacturer is subcontracted by Infineon to make 100000 chips. They make 200000 instead, 100000 go through the whole process and the other half not and then the chinese manufacturer sells them very cheap because they don't have the expenses Infineon has - R&D, marketing, distributor's discount etc. Another example - electrolytic capacitors 2200uF/63V. They start failing and when we opened them inside the big can you find smaller capacitor - 2200uF but just 35V Smiley. So stick with the US authorized distributors and don't bother ordering parts from China. You know what they say - if it is too good to be true probably it is Smiley.  $1.88 vs $0.1 is not giving you any room to think about it Smiley.
Logged
Faros
Senior Member
****
Offline Offline

Posts: 253

Thank You
-Given: 125
-Receive: 178


« Reply #2 on: November 22, 2013, 12:22:41 00:22 »

The chip is sold within a complete modular power supply priced at 2$ Qty 100.
http://www.banggood.com/Wholesale-DC-DC-LM2596-Converter-Buck-Adjustable-Step-Down-Regulator-Power-Module-1_2-35V-p-46754.html
The strange thing is that it has 100% positive user review from 5 user !!
Logged
pickit2
Moderator
Hero Member
*****
Offline Offline

Posts: 3816

Thank You
-Given: 567
-Receive: 2049


There is no evidence that I muted SoNsIvRi


« Reply #3 on: November 22, 2013, 12:23:29 00:23 »

Does anyone have a clue how on earth can the Chinese sell at such price tag? …    
as reksbg says
You have a few things to think about, one the fakes these are down right fake /out of spec devices, radio shack used to sell packs of devices transistors remarked.
two new old stock, a plant has finished a order, and unused parts are no longer under control standards/ can't trace how they have been handled.
Then you have the reclaimed parts, scrap boards striped of components, I think I have bought some of these in the past.
Also they use china post, almost free to use, but they charge you $10 postage.

Look at what people say who have bought from them, I have a few sellers that don't charge till I have the items.
If they offer free post and small orders, buy a few days apart then you have a chance the item slips through customs & taxes are not charged at full rate, or not all.
Logged

Note: If you have no posts other than, I want or reporting a dead link Then you can't complain If I remove your post So Stop Leeching
Faros
Senior Member
****
Offline Offline

Posts: 253

Thank You
-Given: 125
-Receive: 178


« Reply #4 on: November 22, 2013, 01:39:52 01:39 »

@Pickit2
I am not a manufacturer myself, I design circuit for electronic products manufacturers. The completion of the design takes account of sourcing the best price / performance ratio of components as designed. I always keep in mind the cost of components during the design phase as I judge best designs as those which satisfy the cost saving factor among other design factors like performance, integrity … etc.
The problems associated with “out of specifications” component in design phase is painful, most likely they will not comply to SPICE models provided by semiconductor manufacturers and used in simulation. My designs are judged by ratio of failed / passed products over time. Promoting for Chinese component is not in my favor and I don't recommend it however I sometimes face this questions by some clients and I needed a practical answer out of speculations.   
Logged
Ichan
Hero Member
*****
Offline Offline

Posts: 840

Thank You
-Given: 312
-Receive: 387



WWW
« Reply #5 on: November 22, 2013, 03:06:57 03:06 »

Try them first, some of them 90% as good as the original - some is just burnt on 20% of the power rating.

I use china made Lm2576 at 2A with no problem, but the IRFZ44 mosfet gets very hot only at 2A while the original one stay cool at 10A.

-ichan.
Logged

There is Gray, not only Black or White.
Sideshow Bob
Senior Member
****
Offline Offline

Posts: 457

Thank You
-Given: 160
-Receive: 495



« Reply #6 on: November 22, 2013, 10:31:15 10:31 »

Another example - electrolytic capacitors 2200uF/63V. They start failing and when we opened them inside the big can you find smaller capacitor - 2200uF but just 35V Smiley. So stick with the US authorized distributors and don't bother ordering parts from China. You know what they say - if it is too good to be true probably it is Smiley.  $1.88 vs $0.1 is not giving you any room to think about it Smiley.
I have seen pictures of this. But thought it was a some sort of student practical joke.
Logged

I really am ruggedly handsome, aren't I?
DreamCat
Active Member
***
Offline Offline

Posts: 235

Thank You
-Given: 130
-Receive: 77



« Reply #7 on: November 22, 2013, 11:52:26 11:52 »

yeah, there are many guys has no conscience in china. and lack of supervision from government.
I also bought some defective chips,it cause project stalled.
Logged

May be I expressed the wrong meaning, sorry for my bad english. Please correct it for me if you can.
pickit2
Moderator
Hero Member
*****
Offline Offline

Posts: 3816

Thank You
-Given: 567
-Receive: 2049


There is no evidence that I muted SoNsIvRi


« Reply #8 on: November 22, 2013, 02:05:36 14:05 »

I have seen pictures of this. But thought it was a some sort of student practical joke.

wonder if it's a double bluff, I bet there is a tant cap inside the rubycon. Tongue
Logged

Note: If you have no posts other than, I want or reporting a dead link Then you can't complain If I remove your post So Stop Leeching
EHHS1979
Newbie
*
Offline Offline

Posts: 20

Thank You
-Given: 2
-Receive: 0


« Reply #9 on: November 22, 2013, 05:06:25 17:06 »

This is a great topic, since it is getting much attention in my line of work.  The concern is "Counterfeit parts", and especially with parts no longer made.  You could get the very expensive Rochester reproductions, you will want to stay away from counterfeit parts, because most will fail, and if they don't fail specifications at room temperatures, try at the extreme temp ranges.  Burr Brown devices is a big target with counterfeiters.
Logged
reksbg
Junior Member
**
Offline Offline

Posts: 49

Thank You
-Given: 22
-Receive: 45


« Reply #10 on: November 23, 2013, 12:25:36 00:25 »

The one from the picture is easy to catch because it says 6800uF but inside is 2200uF. The receiving inspection guys will catch it with lust simple measurement. And I don't think the chinese manufacturer will spend the money for Rubycon part inside that is probably more expensive than the real noname 6800uF/50V capacitor  Grin. Our subcontractor that assembles the pcbs bought 20000 pcs from a parts broker and when they tried to contact the chinese manufacturer there was no longer company like that Smiley
« Last Edit: November 23, 2013, 12:27:48 00:27 by reksbg » Logged
Faros
Senior Member
****
Offline Offline

Posts: 253

Thank You
-Given: 125
-Receive: 178


« Reply #11 on: November 23, 2013, 09:23:40 21:23 »

In my line of business I have found those who care about authentic components with near DATE CODE to insure flawless soldering as older components  are subject to rust which impact proper soldering on automated Pick’nPlace , on the other hand I have found those who care to spend great deal of time to reach the cheapest possible Chinese components and pray that products pass the warranty period.
Logged
Pages: [1]
Print
Jump to:  


DISCLAIMER
WE DONT HOST ANY ILLEGAL FILES ON THE SERVER
USE CONTACT US TO REPORT ILLEGAL FILES
ADMINISTRATORS CANNOT BE HELD RESPONSIBLE FOR USERS POSTS AND LINKS

... Copyright © 2003-2999 Sonsivri.to ...
Powered by SMF 1.1.18 | SMF © 2006-2009, Simple Machines LLC | HarzeM Dilber MC