Faq

PCB DESIGNING

What are good softwares for PCB designing ?

In fact, there is a very good number of PCB design softwares out there. Some serve a specific purpose, while rest are general PCB design softwares. Most of them are paid, while few are open source.

  • Circuit Studio
  • Cadence OrCAD
  • Altium
  • Diptrace
  • Mentor Pads PowerPCB
  • Autodesk Eagle
  • Proteus
  • Circuit Wizard
  • EasyEDA

Out of them, the most popular is Altium. It has a free version to try out as well. The most compelling fact with Altium is it’s user interface. It is one of the most user-friendly PCB design softwares.

Altium is the first preference of most of the professionals. Apart from Altium, Autodesk eagle is an equally good software.

If we talk about free softwares, KiCAD is something which is used for simple designs as well as enterprise grade designs. However, KiCAD is not the most user friendly software. EasyEDA is a great choice, especially for simple designs and it has a huge database of libraries of components.

What is PCB designing ?

PCB stands for Printed Circuit Board. The green colour board you see with lots of components soldered is a PCB.Printed circuit board design brings electronic circuits to life.Using layout software, the PCB design process combines component placement and routing to define electrical connectivity on a manufactured circuit board.

What you see here is fabricated PCBs in a panel. Note that there are no soldered components and they are to be soldered manually or by machine.

PCB design can be single layer, dual layer or multilayer. Multilayer designs have several layers of circuits tucked beneath the top layer, where we use vias to connect different layers with each other. It helps to design a larger circuit in a smaller form factor.

PCBs have pads where the components are soldered . The tracks on the PCB enable signals and power to be routed between physical devices. These components are soldered to both electrically connect and mechanically fasten them to the PCB.

PCB design is done in a software. There are various of them, many are paid like Altium, Eagle etc. while some of them are free like KiCAD and EasyEDA. For PCB design, there is a fixed design flow. Some softwares are capable of handling complete design flow while others are used to accomplish a specific

  • Creating symbols for components that might not be included in the default library.
  • Schematic capture is defining how the pins are going to be connected in the circuit.
  • Footprints are the orientation and shape of components in the actual pcb. We have to create footprints for components which are not already available in the software.
  • The netlist contains the electrical connections between the components on the circuit board, and is usually held in textual format. It is useful for design verification
  • Board layout is defining how your components are going to be arranged on the pcb.
  • Gerber files are something that you are going to give to your PCB manufacturer.

What do you Need To Know About PCB Design & Manufacturing ?

Going from prototyping on development boards to designing Printed Circuit Boards (PCB), there is a lot to know about this process, so let’s see through.

Once your design is complete, there are still a lot of factors that you must know before going into production. Assuming you are done with your design and looking to get into manufacturing of your PCB, you are happy with the proposed outcome and looking to manufacture your PCB.

If your number of quantities is more, consider Surface mount technology as the components can be soldered by machine. Also, order your components in reels for SMT machine automatic pick-up, not in separate packages. Always order 5-10% extra for scope of mistakes. Decide on the surface finish you’d like (ENIG (Electroless Nickel/Immersion Gold), DIG (Direct Immersion Gold), OSP (Organic Solderability Preservatives…etc.). Your manufacturer might ask you for the thickness of PCB. You are free to choose, but note that thinner PCBs are expensive, also the thickness of the PCBs are dependent on the application for which the PCBs are manufactured.

Through-hole soldering is only beneficial when the number of PCBs is limited and the product is in the prototyping stage as it is cheaper (in terms of labour) than SMT.

Before outsourcing the manufacturing for your product’s PCB, there are points which should be asked from the manufacturer when going for bulk production or for alpha-testing.

  • What minimum order quantity does the company entertain?
  • What minimum clearance can they keep in multilayer Layer PCBs?
  • Do they provide Double Sided Placement?
  • Are these following component types can be assembled at their end ?
    BGA Fine Pitch Parts (QFN, QFP),Small Chip Packages(0201,0402),As many assembly facilities can’t provide assembly service for such components.
  • Do they provide Circular and Odd board Shapes?
  • What timeline do they need for manufacturing and assembly of PCBs?
  • What minimum drill size (for vias) is possible at their end? Do they also make blind or buried vias?
  • How will they procure the components?

These are few of the most important points to be considered.

Moreover, you can get your PCB tested by an external agency. There are many companies doing this, see which one fits the need. In-circuit test is one such test which checks shorts, opens, resistance, capacitance, etc and makes sure they are well under their tolerances, assuring the quality of the components used. This helps in lowering the rejection while in the production Phase.