Finding a correct smd inductor for a macbook board - Page 1
Forum section: electronics / beginners

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 02:51:51 am
content: Hello!I'm having a lot of trouble finding replacement components - when I specify exact values on digikey, mouser and others - there is exactly zero results available.My question is - which values don't have to be as precise? I'm only starting to understand how inductors work.The values:1.2UH-20%-0.12A-1.17OHMcomponent name in the schematicsL5199I'm attaching a screenshot for reference

author: Jwillis
author_rank: Super Contributor
timestamp: February 09, 2021, 03:35:02 am
content: You can go a little higher value for inductance and current rating as long as the foot print (dimensions of the pads ) will fit the board . The resistance shouldn't change by much with a slightly different value .

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 08:18:53 am
content: HelloThank you for the help, tried looking for components again but I'm having a lot of trouble finding proper component. If I kinda match the values parts are not on stock/obsolete. Not sure how high can I go with values

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 08:25:56 am
content: this one is a good candidate :https://www.mouser.fr/ProductDetail/ABRACON/AIML-0402-1R2K-T/?qs=1vO2EIVe%252BY4LHPMKYaXhkQ%3D%3DEdit: ooops sorry not in stock !Edit2 : they are in stock @ digikey :https://www.digikey.fr/product-detail/fr/AIML-0402-1R2K-T/535-11582-1-ND/2782817

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 08:28:29 am
content: Isn't the difference between 15mA and 120 mA bit too significant? Or am I simply getting it wrong?

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 08:30:52 am
content: The one from digikey is perfect, I also have a big order almost done in that store. But I'm afraid of making a mistake with using incorrect component and I don't fully understand inductor current values yet

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 09:33:23 am
content: re-sorry effectively 15mA will not work !

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 09:37:34 am
content: 51 models available at octoparthttps://octopart.com/search?category_id=4193&inductance=0.0000012&currentrating=%28120mA__%29&dcresistance_dcr_=%281__1.3%29now you have to choose the good package, and something available.

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 09:47:06 am
content: this one from coilcraft seems also almost ok (1µH)https://www.coilcraft.com/en-us/products/rf/ferrite-core-chip-inductors/0402-(1005)/0402df/0402df-102/and you can get it as a sample ...

author: Zero999
author_rank: Super Contributor
timestamp: February 09, 2021, 11:44:58 am
content: Why do you think the inductor is faulty? Is it obviously phsyically damaged? If not, it's highly unlikely to be faulty.

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 04:02:34 pm
content: I had a corrosion and a pretty big short and a burned connector on the circuit the inductor is a part of, just removed everything that did not look good, its usually dead simple to replace components, not this time though

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 04:06:09 pm
content: Quote from: kripton2035 on February 09, 2021, 09:47:06 amWow! Thanks! Thats the stuff, I'm really grateful, you actually spend the time to find it for me, I'll try to get that one!

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 04:14:27 pm
content: Quote from: kripton2035 on February 09, 2021, 09:37:34 amSadly the octopart shares the same problem as other websites, majority not in stock, most of them not even close to 0402 size, and I really don't feel like bothering a manufacturer directly to ask them to send me 10 or 100 inductors, I guess they'll just laugh at me

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 04:22:40 pm
content: When you mentioned octopart I remembered about this website I had in bookmarks(they have really good customer service btw)https://lcsc.com/product-detail/presales_TDK-MLZ1005M1R0WT000_C531288.htmlIt looks like this one will do?

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 05:48:45 pm
content: looks like, but we don't know how much current the touchID needs. if it is 110mA this inductor will burn...

author: mvs
author_rank: Frequent Contributor
timestamp: February 09, 2021, 06:36:46 pm
content: Quote from: kripton2035 on February 09, 2021, 05:48:45 pmBurn? MLZ1005M1R0WT000 is rated for 450mA with 20 °C temperature rise. At 110mA you just get some inductance loss due saturation.

author: kripton2035
author_rank: Super Contributor
timestamp: February 09, 2021, 07:37:22 pm
content: I see 100mA in the LSCS description ?

author: mvs
author_rank: Frequent Contributor
timestamp: February 09, 2021, 09:47:19 pm
content: Quote from: kripton2035 on February 09, 2021, 07:37:22 pm100mA is just a number and unit. I you want to know their meaning, you need to look in the datasheet.https://datasheet.lcsc.com/szlcsc/2003301511_TDK-MLZ1005MR47WT000_C502004.pdfManufacturers usually specify two current values in their datasheets. Isat is current for given core saturation (in this case max. 50%) and Itemp is current for given temperature rise (in this case 20 °C above ambient). On bigger inductors this values are usually much better matched together. But in this case you have Isat=100mA and Itemp=450mA. This means, that you can apply 110mA of current to this inductor without overheating, but there will be large loss of inductance.

author: adrko
author_rank: Contributor
timestamp: February 09, 2021, 11:30:09 pm
content: Thank you for the explanation, you made it very clear and easy to understand!

author: adrko
author_rank: Contributor
timestamp: February 16, 2021, 01:25:18 pm
content: Sadly there is no happy ending to this story:DI have tried to order sample from the Coilcraft but they refused to give it to me because I'm not an engineer designing stuff - that's absolutely understandable!So I went and purchased 10 inductors, my order went through, no issues whatsoever.Then I get confirmation email.Next day I receive a vague email asking me to describe my company and what the inductors will be used for, I did my best to provide an honest explanation.And that's all that I have heard from them, been 7 days now, no response, package not shipped, no refund of my purchase.Its a bit weird and unprofessional in my opinion, or am I simply wrong?I completely understand I'm just a small fry whos ordering 10 inductors, but if its there and available to order am I wrong to assume that I will get what I have paid for?

author: mvs
author_rank: Frequent Contributor
timestamp: February 16, 2021, 06:01:17 pm
content: Quote from: adrko on February 16, 2021, 01:25:18 pmCoilcraft shop?It sad, but just 10 years ago it was much worse.Nowadays, you can buy parts as private person in europe at least at some large distributors, like digikey, mouser, tme...LCSC is also good place, if you do not mind to wait a bit longer.---By the way, why you have not ordered TDK MLZ1005M1R0WT000 from LCSC?I do not like to play Madman Muntz, but this inductor is not very important part.

author: slimmy182
author_rank: Newbie
timestamp: May 18, 2021, 02:29:54 pm
content: Hello! Did you managed to fix this problem? After liquid spill my trackpad and internal keyboard was not working. Only switch a different trackpad and reconnect the old one do the trick! Now keyboard and trackpad works perfectly. Now theOnly problem remain the touchbar, it display image but wont accept touch control.Looking in diagrams i found that there is a component lost:Can be this the problem? Connectin an other touchbar won't fix, still display but not accept touch control