TE
科技回声
首页24小时热榜最新最佳问答展示工作
GitHubTwitter
首页

科技回声

基于 Next.js 构建的科技新闻平台,提供全球科技新闻和讨论内容。

GitHubTwitter

首页

首页最新最佳问答展示工作

资源链接

HackerNews API原版 HackerNewsNext.js

© 2025 科技回声. 版权所有。

PCB Design Tutorial for Startups

102 点作者 poindontcare将近 9 年前

6 条评论

bsder将近 9 年前
A couple things that I wish people had pointed out before I got started with PCB&#x27;s:<p>1) You will spend your life reading datasheets.<p>2) Datasheets lie.<p>3) You will spend way more time in component selection than schematic design or board layout.<p>4) You will spend way more time creating component footprints than in schematic design or board layout.<p>5) Lay out the board by hand. You will waste more time fighting an autorouter than if you just laid it out.<p>6) A 6 layer board is not that much more expensive than a 4 layer board and is <i>VASTLY</i> easier to lay out. 2 layer boards should be avoided unless you you are a masochist or every fraction of a penny <i>really</i> counts.<p>Some of the given advice is a bit off.<p>1) He doesn&#x27;t put enough emphasis behind avoiding BGA. BGA should be avoided like the plague. Period. It will only cause excruciating pain.<p>2) Small QFN isn&#x27;t that hard to deal with ... if you tweak the PCB footprints a touch (make sure you have .5 mm of bare copper outside the package outline and you can treat them like QFP).<p>3) 0603 is actually pretty small. Most people should stick with 1206&#x2F;1210.
评论 #12060322 未加载
评论 #12060298 未加载
评论 #12061702 未加载
评论 #12060576 未加载
评论 #12061150 未加载
评论 #12060559 未加载
评论 #12060269 未加载
评论 #12061539 未加载
评论 #12060242 未加载
honkhonkpants将近 9 年前
A long article that says almost nothing. Instead of choosing trace widths and layer count and component sizes at random, take a week to read and understand the very useful book &quot;High Speed Digital Design&quot; by Howard Johnson. Despite the name it concerns itself more with the analog domain than with the digital. Very useful information about the behavior of traces and holes in boards.
评论 #12060179 未加载
评论 #12060248 未加载
评论 #12060022 未加载
jwr将近 9 年前
Here&#x27;s something I don&#x27;t get: why discourage people from using QFN packages?<p>QFNs are only a problem if you are hand-soldering your boards with a traditional soldering iron. Which is nuts. These days everyone should have a soldering station with both traditional iron and hot air — and soldering QFNs using hot air is straightforward and easy.<p>Besides, the article is about manufacturing, so you aren&#x27;t likely to solder those QFNs yourself. So why discourage them?<p>I think QFN and DFN packages are fantastic. They save lots of board space (and believe me, board space matters a <i>lot</i> in all designs, more than you think!), have good thermal properties, lack of leads makes for better low-inductance connections, less material means lower price. And most still have pitch of 0.5mm or more, so you can use the same design rules and same PCB pricing. Everything is great about them.<p>BGAs are a different matter, but not for the reason most people think: they are problematic not because they are difficult to solder, but because you need much tighter PCB parameters to be able to route all the signals. In particular, via size is the biggest problem. You need really small vias that can be placed between four BGA balls.<p>I dislike the hate being poured onto QFNs. I think it is a relict of the past: back when hot air was expensive and &quot;strange&quot; and people tried to solder everything by hand using a soldering iron, QFNs were the enemy. But these days they should not be.<p>The unfortunate effect of hobbyists hating QFNs is that some manufacturers (Freescale&#x2F;NXP, notably) later class certain chips as &quot;hobbyist&quot; and don&#x27;t provide QFN packaging at all. And believe me, if you&#x27;re designing a wearable device, the difference in size between a QFN-64 and an LQFP-64 is monstrous. Providing no real advantages, because both have 0.5mm pin pitch.<p>So, while I would agree with the author that BGA packages are best avoided, I would encourage everyone to actually go ahead and use QFN&#x2F;DFN packages. They are better in every respect.
zw123456将近 9 年前
Nice overview article. I have been doing PCB&#x27;s for about 3 decades and here are just a couple of little tricks I have learned over the years, some are too long to go into here, but just a couple quickies maybe will help someone out:<p>1) Often the chip manufacture provides BSDL files which often times contain the foot print info and a lot of CAD tools have macros that will read them in and create your foot print for you.<p>2) There are often foot print libraries already out there you can download or are provided by the CAD software. But in either case, don&#x27;t trust them, there are often errors, get your parts first, do the PCB layout, print it out on a good printer (usually the CAD SW will print it to scale and test fit everything.<p>3) There is a big difference between doing prototype boards and production boards. For prototype boards, make them big because you will have mistakes and will probably have to black wire (cut a trace and fix) it. I often use 2 layer or 4 layer for prototypes because it is easier to do fixes. If you CAD SW does auto layout then it is not that big of a deal as long as the board is large enough for it to route everything for you. For Production PCB&#x27;s it is a different story and a lot more work to do right and I recommend farming it out if you can afford to.<p>4) I agree that part selection is critical but also, if you have simulation software either a separate program or in your CAD system, doing simulations can save you a lot of time. If you don&#x27;t have simulation SW check into it, there are some decent free ones to learn on but to get serious you have to pay a lot.<p>5) For complex designs, I do separate prototype boards, one with the FPGA on it, another with the MCU and another one with the analog on it and so or, sort of a unit test approach (sort of like dev-ing SW) that way you can swap out sections that aren&#x27;t working for you without throwing away a board full of parts, it is more effort but if you plan it out it can save you time and money.<p>6) I agree with the BGA comments, don&#x27;t use those types of components unless you have a reflow oven and know how to use it, it is easier to debug QFN and QFP type packages since all the leads are exposed for inspection. You can often get parts in either package type and when you go to production you can always swap out to the smaller package later. If you have to use those for prototyping check if the manufacturer has a prototype board for it already it can be easier to just use an off the shelf one.<p>A lot of people say the first board is a throw away, but that can be expensive for a production one so I have learned these tricks for prototyping so when you get to production you can avoid that bad first board.
评论 #12060924 未加载
turnip1979将近 9 年前
I&#x27;m in the Bay area and a hardware hobbyist (software is my full time gig). I see tons of meetups for SW but almost nothing for electronics hardware. Any recommendations?
arcticbull将近 9 年前
Also, ChipQuick is great. It&#x27;s super-low melting point solder you can use to easily rework SMD components. This thing has saved my ass too many times to count as a hobbyist :) Was able to get away without a reflow station for the small stuff I&#x27;ve been working on.<p><a href="http:&#x2F;&#x2F;www.chipquik.com&#x2F;store&#x2F;index.php?cPath=200" rel="nofollow">http:&#x2F;&#x2F;www.chipquik.com&#x2F;store&#x2F;index.php?cPath=200</a>