EEBookshelf: Choosing and Using Bypass Capacitors (AN1325.0)

While companies seem to place less importance on writing “general-purpose” app notes and white papers these days, one of the best treasure troves of real-world, time-tested information on the design and development process is in the sea of app notes produced and compiled by most of the big players in the semiconductor industry.  There’s an amazing amount of insight buried in some of these documents, going from introductory concepts (unfortunately this is exactly the kind of stuff you see less of these days), through to the narrowest fields of interest.  While the best reference books are always a bargain in terms of knowledge-imparted-per-dollar-spent, it occured to me that it might be nice to mix in some app notes and white papers with the weekly book review.

This weeks recommended reading?  … click through to find out!

This weeks recommended reading is AN1325.0 from Intersil: Choosing and Using Bypass Capacitors. While this might be old hat to people who have been at this for a while, questions like what value of capactor should I be using and why, what’s the difference between a tantalum, electrolytic or ceramic capacitor and when should I choose them, etc., are things we’ve all asked at some point, and they aren’t always as clearly explained as they could be.  While all of these app notes and white papers are aimed at engineers or engineering students, meaning they assume a certain familiarity with some terms or ideas, this app note by Intersil does a good job of explaining the basic of capacitors … and hey, it’s free knowledge.

I’m going to dig through my “app notes” folder and dig out some of the best ones for future recommendations, but do you have some absolute favorite oldies that you found valuable?  Leave a note in the comments sections and let everyone else know about it.  There’s definately gold in them there hills, if you just know where to dig.

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  1. stuff like this is really great, thanks for sharing, and if you could make a log of them somewhere as a resource above and beyond these blog posts that would be great!

  2. Good stuff, keep it up!

  3. Malcolm Tredinnick

    Please do keep posting stuff like this. Whilst it may be old hat to a portion of the readers here, I can’t be alone in getting more interested in electronics as hobby much later in life. Without tips like this, picking up this information would be much harder.

  4. I’m a little worried that the table ends up mixing “classes” of capacitors (electrolytics vs not) and thus getting some of the comparative qualities wrong. For example, is the leakage of a tantalum capacitor really “low” compared to plastic film caps (listed as “medium” leakage)? I thought that all varieties of electrolytics had pretty high leakages compared to any sort of film cap… ( )

  5. If this is interesting reading to you then this post about decoupling caps and grounding issues probably is too:

  6. I’m excited about this series of blog posts!
    I have understood the basics of capacitors for a long time, but when I go to use it, I feel like I am doing cargo cult design!

  7. One of the interesting items was choosing different package sizes when using several different values in parallel for broadband noise bypassing.

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