8 Replies Latest reply on Nov 25, 2019 8:35 AM by jw0752

    SMD Reference Book

    jw0752

      Tonight I was researching a circuit board which was populated with many surface mount devices. I decided to try to identify some of the devices using the meager markings supplied coupled with test procedures. Here is the board:

       

       

      Once I got to searching the internet I came across this publication that really helped me identify many of the components. If you work with SMDs and haven't come across the SMD Code Book before check out this link. I have down loaded it and even though it is 80 pages I have printed it as I related better to paper than computer screens. Not only does it identify semiconductors but also resistors and capacitors. I was able to ID several of the semiconductor devices on the board in just a few minutes.

       

      http://www.sphere.bc.ca/download/smd-codebook.pdf

       

      John

        • Re: SMD Reference Book
          genebren

          John,

           

          This is a pretty good list.  Although it is limited, there is a lot of good data here.  I have always wished for a complete list, but alas, some device manufactures do not even list their codes on the specification sheets.

           

          I once had a incorrectly bagged and labeled part delivered from a distributor.  The part had the correct number of pins, so I did not suspect anything, so I mounted it on to the board.  I spent days trying to understand why the circuit was not working, trying several different firmware variations, but nothing worked.  I finally checked the markings and noticed that it did not match.  I contacted the distributor and they sent out the correct part, which of course worked on the first try.  I have always wished that the distributors would mark the bags with the part markings, so you could do a visual inspection prior to assembly (without having to find the code in the specification).  The other issue that I have had, is that the silicon versions are not listed on the labels, nor are they listed on the distributor's websites.

           

          Thanks for posting!

          Gene

          3 of 3 people found this helpful
            • Re: SMD Reference Book
              jw0752

              Hi Gene,

              I doubt that they will be able to bring order to SMD markings. For one thing the technology is changing so fast there is not time nor incentive to put the work in. I was surprised to find a list as complete as this one is. I always learn things when I go exploring. Last night I learned from the list that some of the little 3 leg SOT 23 that I assumed were transistors are actually 1N4148 diodes and the third leg is NC.

              John

              3 of 3 people found this helpful
                • Re: SMD Reference Book
                  genebren

                  Hi John,

                   

                  Interesting that they would put a diode into a 3-pin package, but then again, it does make assembly a little easier as you don't have to worry about orientation.  I always like placing parts with an odd number of leads, as there is one less thing to check.

                   

                  Gene

                  3 of 3 people found this helpful
                  • Re: SMD Reference Book
                    shabaz

                    Hi John,

                     

                    Useful document!

                    I used to have a sheet with old (e.g. obsolete) manufacturer logo markings for ICs, e.g. Signetics, Ferranti, etc, but I can't find it now. I'll post it if I can locate it.

                     

                    Regarding SOT-23 diodes a popular one is BAT54, which is a single schottky diode, but also available with three suffixes, which cover all the combinations of two diodes with a common node (e.g. both anodes connected, or both cathodes connected, or anode to cathode connected). Quite handy sometimes. For a single general purpose diode, BAS16 is popular, it is like a SMD alternative for an IN4148 almost (some differences).

                    4 of 4 people found this helpful
                • Re: SMD Reference Book
                  jw0752

                  I found another useful website for identifying SMD markings.

                   

                  http://www.s-manuals.com/smd

                   

                  John

                  2 of 2 people found this helpful
                  • Re: SMD Reference Book
                    lorrainebeadling

                    Thanks for sharing this book about SMD devices. As a beginner, these days, I am learning SMD soldering. Though according to instructors, it is not much tough but as a newbie, I found it little tough. That's why I always prefer some inspirational stuff about SMD soldering. So, if you have any book or link in this regard then you can share. Secondly, we got an assignment about the Passive and Active SMD components. Basically, we need to enlist all of them with uses and found this article https://neodenusa.com/blog/surface-mount-electronic-components  little informative in this regard. However, it would also be great if you share any detailed video about the uses of SMD components and their proper applications.

                      • Re: SMD Reference Book
                        jw0752

                        Hi Lorraine,

                        I am sorry I haven't any more information at this point. As to your question about the uses of SMD parts, the uses are in the knowledge and experience of the people who need them to build something (a circuit). I like to think of all the electronic components regardless of their physical configuration (through the hole, SMD, or other) as LEGO blocks. Each LEGO block has a different physical shape and application but these parameters do not dictate what one can build with them. A good knowledge of all the size and shape resources of the LEGOs does however give the experienced builder options to build better and more elegantly than can a person without this knowledge. Continue to pursue knowledge of how each type of electronic component reacts to the presence of electric flow and fields. This will give you the resources that you need when you want to design a circuit that does a specific task. It may seem like a daunting task but a good knowledge of the foundation of electronics will serve you well as you continue to build your knowledge and experience.

                         

                        John

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