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26 DESIGN007 MAGAZINE I JUNE 2020 malized. Then, that information is displayed on the website on the part detail page. Shaughnessy: The app notes are more like pos- sible applications, whereas the datasheet is the so-called "real" data. Lipman: Yes, but there's an educational part to app notes too. A good example might be switch-mode controllers for power supplies. A switch-mode controller is often a very flex- ible device that a designer can use to realize a variety of power supply topologies, such as buck, boost, flyback, SEPIC, etc. The datasheet would typically give you detailed information on the part and maybe a single or two pos- sible typical supply realizations. But the app notes are where you could go to get examples of specific supplies that discuss the higher-lev- el issues. Often, you can add additional exter- nal components to supply design to adapt it for your specific purpose, like a higher voltage, inverted polarities, isolated or non-isolated, etc. The app notes are one of the places that I would look to for this kind of information. Shaughnessy: If people shouldn't automatically trust app notes and they have to verify them, this would take you an impossible amount of time, right? Lipman: It would definitely take time, but pro- fessional ethics would be the reason for that. If I'm an aerospace designer and I'm putting something on the SpaceX Dragon that people are going to be traveling in and lives could be at stake, and I specify a charger IC based on what was represented in the datasheet or app notes but didn't test it, that would be a failure of professional ethics on my part. For instance, NASA doesn't allow you to use parts that aren't tested under the conditions that they deem to be important. Matties: But if you're saying the datasheet is a guarantee, there should be no reason to test it. Lipman: It's a difficult line to tread. When I say it's a guarantee, I mean it's trying to be a guar- antee, or it is in many ways like a guarantee. But from a professional engineering standpoint, depending on what the situation is and how im- portant something is, someone is going to be left holding the bag if something goes wrong. Matties: It's still buyer beware. There are hundreds of thousands of components available, and many have similar specifications, making correct data even more critical.

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