Passive SMD size for mainstream 50 USD consumer goods - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: August 16, 2024, 06:39:08 pm
content: What is the mainstream RC SMD size for middle to upper-middle quality, mass-production consumer devices at50 USD/UK Poundsprice point (recommended retail price at web-store or street-store)?50 USD is still a bit from 150 USD that is entry level cell phone demanding absolutely cutting edge technology.Many thanks

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2024, 07:54:50 pm
content: 0603 is the size that any equipment can place reliably without a whole lot of tuning and yield issues. If you have space on the board and other design constraints allow, do not go smaller.

author: Wilson__
author_rank: Frequent Contributor
timestamp: August 17, 2024, 04:06:59 pm
content: Many thanks. We need to go as small as practically possible. Will PCBWay or similar companies handle (imperial) 0402 or even 0201?

author: Siwastaja
author_rank: Super Contributor
timestamp: August 17, 2024, 04:32:43 pm
content: Any real manufacturer, even cheapest Chinese ones, have absolutely no issues with 0402 or 0201. I think advice to stay on 0603 is from 2010 or so and considers lowest-quality random fabs of that time.If there is a chance you would use a $1000 DIY P&P kit, or use as a CM some tiny company which uses something like that, or if you hand-assemble a lot, then limiting to 0603 might be a good idea. Otherwise than that, I find that forcing one's design into 0603 has negative influence on ease of design and board size around large pin count devices such as microcontrollers. Difference in part or assembly cost is negligible, but your design ends up larger, or if you have size constraints, you spend more time routing the PCB, placing bypass caps and series resistors further away from ICs just so you can fan-out the signals, and for what - because you read on forums to avoid 0402.Really, only reason to artificially limit yourself to 30-year old technology node is if you hand-assemble a lot and have troubles with smaller parts.Then again, sometimes it doesn't matter. For example all my 0.1-1uF generic bypass caps and 33R series termination resistors and 4.7k pull-ups and similar are in 0402, because many of them often go in tight spots close to ICs, but then if I design e.g. an amplifier circuit or voltage regulator feedback circuit might as well use 0603, doesn't usually matter at all. 0402 is in pretty sweet spot because you can still quite easily hand-assemble prototypes (it's not asniceas 0603, butdoableand that's enough for prototypes), yet it's small enough even in real production so that you don't start feeling like you are wasting a lot of space for nothing.Yes, PCBWay will definitely handle 0201, like any company which has significant production numbers. They use real manufacturing equipment, not only to support modern process nodes, but simply because modern professional equipment pays itself back in production time. And 0201 is pretty standard stuff since early 2000's.If you haveactualminiaturization need, then use 0201 for the cheap CMs, and if you need even smaller, then discuss about it with the CM in advance, noteveryonecan do 01005. But claims that 0402 is somehow iffy are ridiculous, it's not year 1999 now.TLDR:0402 for generic work when size does not matter that much but you don't want to arbitrarily waste space either0201 for miniaturization but still workable with usual cheap-ish fabssmaller: work with the CM

author: Infraviolet
author_rank: Super Contributor
timestamp: August 17, 2024, 09:28:33 pm
content: "upper-middle quality, mass-production consumer devices"The sort of device the parts are used in is much less important that the electrical requirements for each part. They really depends on what role each SMD part is playing, for parts with higher power dissipation you have to go with a larger package. For parts which need to maintain physical clearance distances due to voltage isolation requirements, again, larger packages. You simply won't find SMD caps above particular capacitances in particular sizes, atleast for a given voltage rating. 10uF of any rating in something smaller than 0603 is rare, 10uF rated for >12V in < 0603 probably doesn't exist.Your reply #2 is useful, it shows you're looking to optimise for a small size, but I suspect there isn't really much of a standard for devices in particular price ranges. You simply do what works for your situation. The price involved in getting smaller passive parts placed, still probably account for much less than other elements in your bill of materials and/or prices for other aspects of device construction and assembly.0603 is certainly good for making devices, particulary during prototyping, easy to test and rework by hand.

author: glenenglish
author_rank: Frequent Contributor
timestamp: August 17, 2024, 11:03:35 pm
content: Siwastaja is right-on.Yes, all the chinese machines say "0402 / 0201". but the reality is they are bullsh1itting. stick to 0603.All 0402 and below systems need some degree of tuning, specifically- pickup tuning. Tape varies, sprocket advance varies, all sorts of annoying things begin to affect 0402 and lower.If you are using a CM (contract manufacturer) they'll do 0402 like it is a walk in the park- but cost may still be higher (in the west where labour costs dominate) because the smaller parts requires more operator intervention.

author: Jackster
author_rank: Frequent Contributor
timestamp: August 17, 2024, 11:14:54 pm
content: Quote from: ataradov on August 16, 2024, 07:54:50 pmAs a CM, this...There is no need for anything smaller unless space is a problem.It is also easier to prototype, assemble and rework. All lowering costs.

author: SCSKITS
author_rank: Regular Contributor
timestamp: August 18, 2024, 12:08:11 am
content: I would stick with 0402 or 0603 if you can fit. For my small industrial cameras back in 2005 I was using 0402s. All competent PCB assembly facilities can easily do 0402.For hand assembly I use 0603 or 0805. Larger parts only if I need a higher power rating.With the smaller parts, watch the power handling capability, not usually a problem with Digital, but can be with Analog.In some cases, voltage rating could also be an issue with the smaller parts, for example YAGEO 0201 parts are rated at 25V.ed

author: exmadscientist
author_rank: Frequent Contributor
timestamp: August 18, 2024, 02:15:19 am
content: I would turn this around a little bit... any CM who complains about 0402s being trouble (that's EIA 0402, so metric 1005) is not a company I want to give any business to. There are so many things that go in to a successful build, and so many tiny modern parts, that if you can't nail 0402 day in and day out, you are probably going to give me trouble aboutsomethingthat you shouldn't, and I don't need that in my life, not when there's so much competition out there.I also find that 0402 is the sweet spot for cheap and available parts, compact layouts, and fair reworkability, so I design the bulk of my production-grade stuff to be mostly 0402. I do still do many or most analog sections in 0603 for a number of reasons, but I don't hesitate to drop down if the size is causing issues. For actual tiny stuff (wearables and such) I start at 0201, but I try to get other people to do those....

author: Siwastaja
author_rank: Super Contributor
timestamp: August 18, 2024, 08:47:41 am
content: Quote from: exmadscientist on August 18, 2024, 02:15:19 amThis is exactly the case. We also used a very small CM for very small batches, and while it was kinda fun and interesting to work with them, now we are working with a real CM instead; it's still close to us and still provides good turn around times and pricing is not that much higher even for very small batches. The very small CM was a nice company and nice guys who put a lot of effort and sold their time to us with surprisingly low prices, but it was... all hobby stuff. They did struggle with not only 0402, but also things like paste printing.If youknowone such company, and if youlikeworking with them, then by all means adjust your process to early 1990's component sizes. Otherwise than that, I'd primarily suggest not doing business with any CM which asks you to use 0603 and bigger. They are hobbyists; their machinery is hobby level, and/or they don't do this stuff day in day out, to know how to use those machines.The problem with any fab that asks you to use 0603 and bigger is they don't scale up. You spend effort on limiting your design time options to match that fab, then if your sales end up doing better and you try to order 10000 they say "no can do". There is always some effort required to talk with CMs, therefore if aiming for a real product, talk with real CMs from the get-go.

author: Wilson__
author_rank: Frequent Contributor
timestamp: August 18, 2024, 10:12:00 am
content: Many thanks. For (imperial) 0201 (0.6 x 0.3mm), is PCBWay a properly equipped large-scale contract manufacturer? Any other advises?Is Asian contract manufacturer best quality (for consumer electronics)?I do not need high volume but best to start with a large and proper one that share the huge capital equipment over many automated orders. Proper factory are hugely complex with lots of knowhow. You can see one-hour youtube video just to show all steps and machines.Photo of a Raspberry Pi RP2040 colour LCD watch with sensor and batt charger, using 0201 imperial RC, at 17USD web-retail price. Seems a small project among the huge mass manufacturing of consumer goods.Many thanks