End Of Life component - Page 1
Forum section: electronics / general

author: greencardigan
author_rank: Contributor
timestamp: October 22, 2019, 01:13:19 am
content: Hi,I've been making and populating small quantities (about 50 per year) of the boards attached. I did not design the board but I have access to the Gerber files.I have just received an End of Life notification for one of the parts, the resistor network identified in the attached image. And Digikey linkhttps://www.digikey.com.au/short/pd82t0I guess I have a few options.1. Buy a large quantity before they sell out. I think 250 should last me quite a few years.2. Buy a substitute. The only potentially suitable one I can find at digikey ishttps://www.digikey.com/short/pd827fbut it's 3.2mm wide instead of 2mm.3. Use 0603 individual resistors instead of the array.I'm thinking option one is probably the way to go but I'm fairly inexperienced regarding board design and component selection.

author: pisoiu
author_rank: Regular Contributor
timestamp: October 22, 2019, 04:29:43 am
content: I don't think it's a good idea to use individual 0603. They are too close to each other and will cause short circuits. And pad size looks smaller to me than 0603.

author: Mangozac
author_rank: Frequent Contributor
timestamp: October 22, 2019, 04:44:34 am
content: I'd modify the design to suit 0603 resistors spaced out a little more - it's not like the board real estate is tight and even just modifying the top layer Gerber to suit isn't too difficult.

author: beanflying
author_rank: Super Contributor
timestamp: October 22, 2019, 05:04:30 am
content: A bit random but I actually have a slightly tweaked V7 of this board out on the bench at present. Loose 0603 beside the network and 2.5mm pins above it for reference.Very slight track tweakage would sort it out and keep it functionally the same moving forward with discrete resistors.Also consider this a free plug as another member and I have been talking about the OP over the last weekhttps://github.com/greencardigan/TC4-shieldhttps://www.tindie.com/products/greencardigan/tc4-arduino-shield-v602/

author: mariush
author_rank: Super Contributor
timestamp: October 22, 2019, 06:03:36 am
content: You could just redesign the board to use individual resistors, there's plenty of room on the circuit board for them.While you're there, you could also align the leds OT1 and OT2 and/or maybe move them a bit to the left top corner of the board so they'll be like where the reset button is placed but on opposite side, easily viewable by a person if there's another pcb on top.Same for the power on led.And while you're there, maybe have the internal headers right angle, so that if you stack another board on top the pins of those internal headers won't touch the bottom of a board.

author: AndyC_772
author_rank: Super Contributor
timestamp: October 22, 2019, 08:18:41 am
content: https://www.mouser.co.uk/ProductDetail/Panasonic/EXB-S8V102J?qs=49iMgXsaVV4ip0WF0RT1DQ%3D%3D

author: Gribo
author_rank: Frequent Contributor
timestamp: October 22, 2019, 10:25:53 am
content: Check Bourns for an alternative resistor network. Digikey has it in stock. You are looking for 2008 size, 4 Elements, isolated, 1Kohm.https://www.bourns.com/docs/Product-Datasheets/CAT10.pdfI would have bought an entire reel of these parts, just in case.

author: greencardigan
author_rank: Contributor
timestamp: October 23, 2019, 04:28:38 am
content: Thanks for all your suggestions. I think I will keep buying the usual part from Digikey until they're sold out, then switch to another compatible part from Mouser of RS Components.I found this parts at RS Components which should be suitable I think.https://au.rs-online.com/web/p/products/1729488/The price is right and it's free shipping!I also found the sch and brd files, so modifying the layout is also an option now.

author: ebclr
author_rank: Super Contributor
timestamp: October 23, 2019, 12:21:03 pm
content: This component for sure have many other sources or similar components If all your problem is this 4 x 1k 5% resistors you are a happy man, Just do not stick in only one supplier for sure this is very easy to find and solve

author: Mangozac
author_rank: Frequent Contributor
timestamp: October 23, 2019, 10:23:23 pm
content: As a general question: are these kind of resistor networks really worthwhile using in anything other than high volume and/or super tight real estate designs? The 1000+ cost seems to be higher than the equivalent number of discrete resistors, even when taking the additional placement machine time into consideration.

author: DBecker
author_rank: Frequent Contributor
timestamp: October 24, 2019, 03:51:11 am
content: Quote from: Mangozac on October 23, 2019, 10:23:23 pmYes, they are often worthwhile. If you are hand building boards, they are much easier to place and hold than smaller components, and you get four parts soldered for about the effort of one.I recently had boards built at JLCPCB. Resistor arrays were somewhat less expensive than individual resistors, although both were so inexpensive that the per-joint fee of 0.0015/joint (e.g. 0.3 cents per resistor) dominated. Other board builders charge per component placed, which might be enough to influence the economics rather than just the convenience.I did convert some of the resistor arrays to discrete parts where they were used in resistor dividers. The typical array has a tolerance of 5%, and they won't characterize more tightly within a reel or even within the package. You pay significantly more for 2% or 1% parts (presumably 100% tested and binned). Even the cheapest discrete resistors are 1% and have better thermal stability.

author: exe
author_rank: Unknown
timestamp: October 24, 2019, 05:07:25 am
content: I'd just buy 250 of them. Pros: 1) not so expensive 2) time-saving 3) you don't need to do anything with the board 4) proven to be working.

author: JPlocher
author_rank: Contributor
timestamp: October 25, 2019, 09:40:27 pm
content: Stocking up on the part in question while they are still available is a good idea, but they should be easily second sourcable from others - it may simply be a manufacturing process change (say, from leaded to lead free...) that is making this particular part number go away, and that the replacement / upgraded part will work just fine!If you are worried about only having the gerbers, this looks to be a relatively easy arduino shield to reverse engineer and lay out from scratch using Eagle or Kicad or one of the EDA programs out there - the footprint for these shields is commonly available, which takes care of 99% of the registration concerns.The benefit would be a bit more insulation from component evolution, at the expense of a couple of hours work to reimplement plus a few dollars and a couple of weeks for a quick test run of PCBs.In any case, not the end of the world-Johnedit: realized this is a simple 'duino shield...