1 / 19

Printed Circuit Board Design

Printed Circuit Board Design. Avnish Kumar Dept. of Electrical & Computer Engineering University of Connecticut September 26, 2016. (Based on Prof. Sung Y. Park’s slides, Fall 2014). Printed Circuit Board ?.

msaenz
Télécharger la présentation

Printed Circuit Board Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Printed Circuit Board Design Avnish Kumar Dept. of Electrical & Computer Engineering University of Connecticut September 26, 2016 (Based on Prof. Sung Y. Park’s slides, Fall 2014)

  2. Printed Circuit Board ? • A printed circuit board (PCB) mechanically supports and electrically connects the electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. • PCBs can be single sided (one copper layer), double sided (two copper layers) or multi-layer. • Conductors on different layers are connected with plated-through holes called Vias. • Advanced PCBs may contain components - capacitors, resistors or active devices - embedded in the substrate. 4

  3. Multi-layer PCB design • 2 Layer PCB design: Top layer and bottom layer • 4 Layer PCB design: Top, Bottom, and two middle layers. 3

  4. Three Elements to be considered • Components : - How to select components? - What values are needed? - What kind of package will be available/are needed? • Printed Circuit Board : - Schematic Design - PCB Layout Design - Prototype board • Case or Box for the prototype board : - Purchase or build by yourself 4

  5. Printed Circuit Board Design Schematic Design 5 PCB Layout

  6. Printed Circuit Board Design A PCB as a design on a computer (left) and realized as a board assembly populated with components (right). The board is double sided, with through-hole plating, green solder resist and a white legend. Both surface mount and through-hole components have been used. 6

  7. Key Elements of a PCB • Pads are where the components are soldered to the PCB. • Traces are the copper tracks that connect pads together. • Via are small holes through the board that link a bottom and top trace together electrically. Traces on the same layer cannot cross, so often, when you are laying out a PCB, you need to jump from one layer to another. 7

  8. Key Elements of a PCB • Silk-screen refers to any lettering that will appear on the final board. • Solder-mask is a layer of insulating lacquer that covers both sides of the board except where there are pads. 8

  9. PCB design procedure • {Specific/Measurable} goals  Design specification • Circuit diagram • Schematic design  Select components Check the dimension  Build a footprint  Make a PCB library  Add parts • Export schematic design to layout design • Route all connection • Design rule check • Generate Gerber files and drill file and zip them • Upload zip file to PCB order website 9

  10. PCB Library design • Component datasheet • Dimension: mil (imperial unit) vs mm (metric) 1 inch =1000 mil, 1 mil = 0.0254 mm 1 mm = 39.3700787 mil DIP component and connector: 100 mil or 2.54 mm • Symbol in schematic vs Exact dimension in Layout • Pad number should be matched in schematic symbol and layout footprint 10

  11. PCB Library dimension example • Male header 11

  12. Tips for PCB design • Keep traces straight, • Try to avoid 90o turns use two 45o’s. • Double, even triple check layout, • Having a fresh pair of eyes look it over, • “measure twice, cut once” idea. • Trace thickness & spacing • Spacing of at least .010”, • 0.030” for In-house • ~0.025” per 1 Amp carrying lines, • Don’t use anything smaller than 0.010” for traces, • 0.030” for In-house milling. • Try to keep all connections on one side of PCB • Take into account component package 12

  13. Tips for PCB design • Keep traces straight • Try to avoid 90˚ turns, use two 45˚ turns instead • Double (even triple) check the layout • Have a fresh pair of eyes look over it • “measure twice, cut once” idea • Trace thickness & spacing • Spacing of atleast 0.01 inches; 0.03 inches for In-house • ~0.025 inches per 1 Amp carrying lines • Don’t use anything smaller than 0.01 inches for traces; 0.03 inches for In-house • Try to keep all connections on one side of the PCB • Take into account the component packages 13

  14. Free PCB design program • EAGLE • Cross-platform, Free with limitations, upgrades from $70 – $1640. A powerhouse in the hobbyist world, EAGLE probably has the most community support. • KiCad • Free and open source, no limitations • Express PCB • Free, no limitations. ExpressPCB is backed by ExpressPCBso this makes it very easy to send your design for manufacture. • DesignSpark PCB • Free, no limitations 14

  15. Making PCBs • Layout your circuit / circuits • Check out http://www.expressPCB.com for some great tips on component layout and power distribution. • Layout is more of an art. • Tight spaces • Lots of connections • Make a 2 level board into a 3 level with vias 15

  16. PCB Design Example 16

  17. Top and Bottom Layer 17

  18. Middle Layers(2nd & 3rd) 18

  19. PCB Design Assignment • Every senior deign team needs to design one PCB during the fall semester • The number of components used should be more than 5 (connectors, surface mount components, through-hole components, ICS etc.) • The number of layers should be 2 or more • Report due date is November 19th 2016 • Report should contain: Schematic, layout design, and free DFM check result† of the PCB. † https://www.my4pcb.com/net35/FreeDFMNet/FreeDFMHome.aspx 19

More Related