Packages naming nightmare SC-88 vs SC-70 vs SOT-363 - Page 1
Forum section: electronics / general

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 29, 2018, 10:16:46 am
content: I am kinda lost why a single package has multiple names. I am now looking at the MUN5233DW transistor and the package is described for example as SC-88, SC70-6, SOT-363. I expect that it has something to do with JEDEC vs JEITA standard. I spent some time with google to find out more but was not very successful. Can somebody explain why a single package has so many names (same with SOT-23 etc.), what they mean and also recommend which naming nomenclature is the most pragmatic for footprints library?Thanks, Jiri

author: Gribo
author_rank: Frequent Contributor
timestamp: November 29, 2018, 12:49:18 pm
content: https://xkcd.com/927/

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 29, 2018, 12:50:38 pm
content: didn't help but made my day

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 29, 2018, 03:14:27 pm
content: Quote from: Gribo on November 29, 2018, 12:49:18 pmSo true, and that's exactly like state commissions. When the government realizes there are too many, it usually creates a new one to figure out how to deal with it.

author: tszaboo
author_rank: Super Contributor
timestamp: November 29, 2018, 03:17:42 pm
content: It should be called of course SOT-323-6.

author: tsman
author_rank: Frequent Contributor
timestamp: November 29, 2018, 03:49:31 pm
content: SC70-6 is slightly different to a SC88 according to the JEITA specs. The package is the same but the tolerance on the lead length is different. You can make parts that are in spec for both SC70-6 and SC88 though hence why your parts say SC70-6 and SC88.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 29, 2018, 04:08:46 pm
content: Seriously though, you can check various packages here:https://www.nexperia.com/packages/(no affiliation with nexperia whatsoever)Also there:https://www.microchip.com/quality/packaging-specifications(nor with Microchip)You can check this instead:https://en.wikipedia.org/wiki/Small-outline_transistor(but I don't guarantee 100% exactness).SOT stands for "Small Outline Transistor".TSOT is Thin SOTI think the SOT* are from Jedec.I think the SC* are from EIAJ and not quite sure what SC stands for exactly.

author: schmitt trigger
author_rank: Super Contributor
timestamp: November 29, 2018, 04:53:09 pm
content: And if one uses a selector tool, it can create confusion.A while back I required some standard CMOS 4046 chips, in SOIC16 format. I went to Digikey's selector tool (which BTW, is one of the best), made all my selections.When the components arrived, I noticed that the component was wider than the PWB footprint.Carefully combing thru the specifications, I see that SOIC16 comes in two flavors:-The 7.5mm wide, which the supplier calls 16-SOIC-The 5.3mm wide, which the supplier calls 16-SOI know, I know....I made a mistake. I should have checked ALL the specs. I should have taken the hint that the W in the part number meant a wider package. I should have understood that if DigiKey is adding a column "Supplier Device Package" in their selector tool, it is there for a reason.But when you are ordering several dozen components in a hurry to meet a deadline, this is yet another pothole in which one could stumble.

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 30, 2018, 09:50:32 am
content: Actually the Farnell's selection tool is the true reason why I started this thread.I just needed "some" digital transistor and used the filter. Then fun started - going through options and finding out which packages are actually same.

author: montemcguire
author_rank: Regular Contributor
timestamp: December 01, 2018, 05:40:56 pm
content: While it seems attractive to use generic footprint types to build a PCB, it is safest to specify a particular device and design the footprint to exactly those dimensions. The generic footprint type codes are useful for component searches, but there's no reason to expect that anything but the manufacturer's specifications will relate to the package dimensions of a device. I gave up on generic footprints long ago, and while it's more annoying, I find that I'm pretty specific when specifying devices anyway, so the impracticality is minimal. Plus, the components always solder to the PCBs extremely well, even with sloppy home assembly. To design footprints, I've been using PCB Library Expert, and it largely works well. With some devices that are poorly specified, or when the manufacturer's dimension tolerances are needlessly large, it can mess up, but in general, with good component dimension data, it applies IPC rules pretty carefully, and ends up with high quality footprints.

author: CarlG
author_rank: Regular Contributor
timestamp: May 03, 2019, 11:14:55 am
content: Found this thread during my search for sorting out the the same issue (or actually land pattern compatibility)....so I might as well add some info. I found this application notehttps://assets.nexperia.com/documents/outline-drawing/SOT363.pdfAccording to that doc, SOT363 is the manufacturer (internal) package code. SC-70-6 and SC-88 refers to JEITA std. TSSOP6 is the Package type industry code.However...I also found this:https://assets.nexperia.com/documents/outline-drawing/SOT323.pdfaccording to which SC-70 is the package industry code...SOT323 is here the manufacturer package code.Obviously, since Philips/NXP/Nexperia are so big their codes has become sort of de facto standard.Regarding land pattern, I haven't come to the point to check what IPC recommends in each case....

author: free_electron
author_rank: Super Contributor
timestamp: May 12, 2019, 01:12:34 pm
content: Quote from: NANDBlog on November 29, 2018, 03:17:42 pmnope. SOT363SOT23 is 3 pinSOT25 is 5 pin SOT23SOT26 is 6 pin SOT23likewise :SOT323SOT353SOT363Simply use IPC nomenclature . much easier and no confusion

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: May 13, 2019, 02:03:37 pm
content: Quote from: free_electron on May 12, 2019, 01:12:34 pmDo you have an easy to understand source for said nomenclature? I would like to use standard names for my parts but tend to always have trouble figuring out how this or that part is named, which results in having many doubled footprints with different names.

author: free_electron
author_rank: Super Contributor
timestamp: May 13, 2019, 05:38:58 pm
content: http://ohm.bu.edu/~pbohn/__Engineering_Reference/pcb_layout/pcbmatrix/IPC-7x51%20&%20PCBM%20Land%20Pattern%20Naming%20Convention.pdf

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: May 13, 2019, 07:31:17 pm
content: Thank you very much.

author: Warhawk
author_rank: Frequent Contributor
timestamp: May 15, 2019, 02:31:36 pm
content: I used to use the IPC naming convention too but found it difficult to use. For instance SMD caps...It is a useful guidance for corporate libraries where every symbol matches a unique product number. However, it is also extremely inconvenient for small designs, hobby etc. I am typically just OK with having a one or two 1206, 0805, 0603. This is also easy to maintain.Using something like "CAPC2012X100_EIA_0805-39_METRIC_2012_200x120x100" starts driving you mad really soon. If you want perfect libraries, then you also need a custom 3d model (because caps have different height...). You also need an alias in the library because if you want the package visible in schematic, CAPC2012X100 is just long....I mean good luck.

author: free_electron
author_rank: Super Contributor
timestamp: May 18, 2019, 02:54:07 am
content: Quote from: Warhawk on May 15, 2019, 02:31:36 pmno need to do thatCAPC2012x100 is enough. no need to add all other suffixes.And yes, you do want the correct 3d models in there.As for the aliea : just store a text string in the symbol.