In Eagle, before you can use a new component, you need a land pattern, a schematic symbol, and a mapping between them to fully define the part. But what if that fails? The symbol and pin definitions are usually pretty easy — just copy the datasheet. The hard part is the land pattern: the collection of copper traces, soldermask openings, silkscreen, and other features that define the part on the PCB. IPC is a standard for printed circuit board land pattern designs.
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In Eagle, before you can use a new component, you need a land pattern, a schematic symbol, and a mapping between them to fully define the part. But what if that fails? The symbol and pin definitions are usually pretty easy — just copy the datasheet. The hard part is the land pattern: the collection of copper traces, soldermask openings, silkscreen, and other features that define the part on the PCB.
IPC is a standard for printed circuit board land pattern designs. The standard attempts to, well, standardize land patterns to try to discourage every PCB designer from having his or her own custom library of land patterns.
IPC takes known good land patterns and combines them with accepted manufacturing tolerances to produce a land pattern that will work for most people most of the time. Increasingly you will see references to IPC in datasheets instead of a land pattern drawing, so access to the standard is becoming more important over time.
Cool, right? The calculator is somewhat tricky to use but if you click the right buttons you can get something like what is shown below click to enlarge. With this information, you can return to Eagle and create a land pattern for your device. PCB Matrix will also sell you premade Eagle libraries , but from their site it was not clear how much they cost. Unfortunately, the calculator is Windows only, so Mac guys like me need to use VMware Fusion or similar to use it.
Can someone create a web version, please? For those looking for this landpattern generator, Mentor Graphics bought the company and started charging for it. Oh no! What a shame that it is no longer available free without a day trial period!
Makes me want to buy the standard itself and spend a couple days writing the trivial scripts necessary to generate the footprints myself, then publish them for free as a library…. I worked out the equations for standard rectangular SMD components, like resistors and chip caps. Most of the time I get the same results as the calculator, but sometimes their results are slightly off could be rounding errors or manually tweaked parts in the libraries, not sure.
My local eagle retailer makes a tool for dumping IPC packages into eagle. I hate having to fire up VMWare just to use simple tools like these, particularly because every time I do, XP needs to update something and nags me about having to restart. Did you try wine? I think there is a mac version.
Most any simple GUI app like this will run under wine. To come up with a land pattern, you usually have a few options: Someone else may have done you a big favor by creating a part definition and uploading it to the Eagle library directory.
Caveat: Use it at your own risk. Whose process were they using, anyway?? Look through the datasheet for the part to try and find a recommended land pattern. Good luck! Google is your friend! Take a guess based on the geometry of the part, assuming you have a mechanical drawing or a physical sample somewhere. Skip and use an IPC land pattern generator. Like this: Like Loading Leave a Reply Cancel reply. Join the resistance. Sorry, your blog cannot share posts by email.
Free IPC-7351 Land Pattern Calculator
Email: sales jjsmanufacturing. Much has been written about the increasing shortages of multi-layer ceramic capacitors MLCC , surface mount SMT resistors and other semiconductor devices. Right now we are seeing price increases and greatly extended lead times. Where components can be found, it is quite possible that they will be offered in smaller package sizes than before. We might find, for example, the popular nF capacitor soon only being available in or packages. It seems the situation is likely to get rapidly worse rather than better.
IPC-7351B Naming Convention for Surface Mount Device 3D Models and Footprints