weatherbox:dragonfruit:pcb_rules

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weatherbox:dragonfruit:pcb_rules [2016/02/24 20:47]
garrettz created
weatherbox:dragonfruit:pcb_rules [2021/09/19 21:59] (current)
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-==== PCB Professional Design Rules ====+====== PCB Professional Design Rules ======
 These 28 Basic PCB design guidelines set out best practice to reduce the cost of your boards and to minimize the risk of errors arising during manufacture. These 28 Basic PCB design guidelines set out best practice to reduce the cost of your boards and to minimize the risk of errors arising during manufacture.
 +
 High power boards have different rules especially in terms of spacing, traces size and power isolation. Manufacturers have different requirements;​ make sure you read their own guidelines before sending your design. Naming and file formats also vary depending on the manufacturers. High power boards have different rules especially in terms of spacing, traces size and power isolation. Manufacturers have different requirements;​ make sure you read their own guidelines before sending your design. Naming and file formats also vary depending on the manufacturers.
-PCB Layout + 
-1. Create your board frame on a 0.05” grid. Make the lower left corner start at 0,0. +//Taken from [[http://​blog.upverter.com/​post/​102541308937/​28pcb|Upverter Blog]]// 
-2. Usually the board frame is rectangular. For specific reasons you could also do other types of shapes such as polygons. +====PCB Layout==== 
-3. Stick parts on a 0.05” grid. You should not break this rule unless you have a very good reason. +  ​- ​Create your board frame on a 0.05” grid. Make the lower left corner start at 0,0. 
-4. Any LED should be labeled with its purpose (power, status, D4, Lock, etc). +  ​- ​Usually the board frame is rectangular. For specific reasons you could also do other types of shapes such as polygons. 
-5. Idem for connectors: e.g Vin, Port1, Batt, 5V, etc. +  ​- ​Stick parts on a 0.05” grid. You should not break this rule unless you have a very good reason. 
-6. Idem for pins where applicable: e.g TX, Power, +, -, Charge, etc. +  ​- ​Any LED should be labeled with its purpose (power, status, D4, Lock, etc). 
-7. Idem for switches and switch states: eg. On, Off, USB etc. +  ​- ​Idem for connectors: e.g Vin, Port1, Batt, 5V, etc. 
-8. When applicable, it is better to avoid having vias go through the silkscreen when adding labels. +  ​- ​Idem for pins where applicable: e.g TX, Power, +, -, Charge, etc. 
-9. Group components together. For example the resistors surrounding a transistor in your schematic will also be grouped together on the PCB. +  ​- ​Idem for switches and switch states: eg. On, Off, USB etc. 
-10. Minimum drill size should be 15 mil. +  ​- ​When applicable, it is better to avoid having vias go through the silkscreen when adding labels. 
-11. Minimum annular ring size should be 7 mil. +  ​- ​Group components together. For example the resistors surrounding a transistor in your schematic will also be grouped together on the PCB. 
-12. 7 mil is the minimum size for traces. 8mil is acceptable. When possible try to keep the traces size to 10mil. +  ​- ​Minimum drill size should be 15 mil. 
-13. Use thicker traces for power lines. 12mil=100mA max, 16mil=500mA max etc. +  ​- ​Minimum annular ring size should be 7 mil. 
-14. 7mil between traces and space is reasonable. +  ​- ​7 mil is the minimum size for traces. 8mil is acceptable. When possible try to keep the traces size to 10mil. 
-15. Avoid 90 degree corners. Straight lines with 45 degree corners are preferable. +  ​- ​Use thicker traces for power lines. 12mil=100mA max, 16mil=500mA max etc. 
-16. Where applicable use a ground pour on top/bottom layers. +  ​- ​7mil between traces and space is reasonable. 
-17. To prevent pours from shorting to traces make sure you use a 10mil isolation setting on any of the ground pour. +  ​- ​Avoid 90 degree corners. Straight lines with 45 degree corners are preferable. 
-Schematic Layout +  ​- ​Where applicable use a ground pour on top/bottom layers. 
-18. Use a GND symbol for all the GND connections. +  ​- ​To prevent pours from shorting to traces make sure you use a 10mil isolation setting on any of the ground pour. 
-19. Use appropriate power symbols for All VCC, 5V, 3.3V etc. +====Schematic Layout==== 
-20. Add color notes to separate a complex design into various smaller bits (for example,​charge circuit, accelerometer,​ etc). +  ​- ​Use a GND symbol for all the GND connections. 
-Footprints +  ​- ​Use appropriate power symbols for All VCC, 5V, 3.3V etc. 
-21. All footprints need a reference designator ​{{refdes}}. If you come across a part on a board that doesn’t have this, you should change it and save the library. For parts requiring it a pin one marker should be defined. +  ​- ​Add color notes to separate a complex design into various smaller bits (for example,​charge circuit, accelerometer,​ etc). 
-22. All footprints need silkscreen indicators showing mechanical sizes, dimensions, or anything wired about the part. +====Footprints==== 
-23. To prevent it from flaking off easily silkscreen within a footprint or board should not go over pads or metal that will be exposed. +  ​- ​All footprints need a reference designator ​(refdes). If you come across a part on a board that doesn’t have this, you should change it and save the library. For parts requiring it a pin one marker should be defined. 
-24. Top component layer should be marked by a red centre cross. +  ​- ​All footprints need silkscreen indicators showing mechanical sizes, dimensions, or anything wired about the part. 
-25. Package outline layers should outline the actual package size. +  ​- ​To prevent it from flaking off easily silkscreen within a footprint or board should not go over pads or metal that will be exposed. 
-26. The Top Courtyard layer should include all of the pins. +  ​- ​Top component layer should be marked by a red centre cross. 
-27. When adding a footprint make sure you add a solder mask. +  ​- ​Package outline layers should outline the actual package size. 
-28. Every new footprint and part will have a human readable description.+  ​- ​The Top Courtyard layer should include all of the pins. 
 +  ​- ​When adding a footprint make sure you add a solder mask. 
 +  ​- ​Every new footprint and part will have a human readable description.
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