What can PCB Layout Engineers do better?

This article is written based on several years of experience working as electrical circuit designer with the PCB Layout engineers. PCB Layout engineering is an artwork and is actually from technical terms should be done with some constraints and guidelines. The major issue with the PCB Layout engineers is not having the clear understanding of the design requirements. While some circuit designers transform to PCB designers and vice versa, the overall problem is that PCB Design Engineers don't have the grip of the design they are working on as it was just passed by electrical engineer. Based on experience wanted to list some guidelines which can help PCB Layout engineers improve their work. One has to remember that PCB Layout engineers are a gateway to success of the Electronics product. While the designer can work day an night designing a circuit, it is the PCB Layout engineer who transforms it into a physical form. 

What PCB Layout Engineer must follow?

• Involve in the design from the beginning and get a clear view of the requirements. If he has a view of the electrical circuit and doesn't have a view of the certification requirements, then the PCB Layout could be a disaster
• Reduce the dependency on electrical engineer and think independently
• Before proceeding to a PCB Layout prepare a floor plan for the layout. This helps to have a clear view of the placement
• Discuss with the Electrical and Mechanical Engineer on the constraints and have a list well before the start of the PCB Layout. Taking care of constraints at a later point of time, could lead to reworks and extended timeline of the project.
• Prepare a list of critical signals in the board, take special considerations w.r.t those signals. Get this list reviewed by electrical engineer. Come up with a combined strategy.
• One of the major issues or a strategic mistake PCB Layout engineers do is that they start placing the controller at the center of the board and start distributing the interfacing circuitry around. While this has been a thumb rule and is the best approach, the modern day design approach is something different. For example, if you want to use Modem chip (for example 3G modem or any technology) in your board, it is preferred that it is at one corner of the board and other circuitry like power, input connector at the other end. This helps isolate the RF circuitry of modem from other digital circuitry. This is where listing the critical signals and the floor planning helps.
• One of the major observations is that, PCB designers who worked on high speed designs (Ex: Processor boards and respective interfaces) and RF designs tend to bring the same practices to a low speed designs (Ex: Micro controllers). This is where PCB designers create complex low speed designs keeping in view/considering the practices of high speed/RF designs. For example, low speed signals might not demand a continuous reference plane for signals, while high speed signals require a continuous reference plane.
• It is always preferable to have a checklist of requirements prepared by PCB designer and get it reviewed by project team (Electrical and Mechanical team) before starting the PCB Layout
• It is a must to define some PCB Layout guidelines prepared for yourself while designing a board. This must be an exhaustive list and must have guidelines added to it as PCB designers work on several projects.
• It is preferable to have a PCB Review checklist which lists basic requirements to have a valid PCB Layout ready. Example could be standard spacing of components/routing from the border of the PCB, silk screen requirements, polarity indications, etc.
• One of the major mistake from a PCB designer is that they do not have DFM guidelines handy and once they release the Gerber they understand that the FAB house cannot manufacture the board with the current state of design. This adds to the timeline of the project. Before starting the design, PCB design engineer must have a view of the FAB house with which they are going with the design and the constraints of that FAB house
• DRC check on the PCB Layout is a must. Most of the beginners in the PCB Layout career do not focus on this.
• Irrespective of the level of complexity, type of design entering the constraints is a must.
• One of the important suggestion for PCB Layout engineer is that as much as possible ensure that you draw or involve in schematic drawing. This helps layout engineers get control over the sections in the design
• One of the major observation is that PCB Layout engineers follow the PCB Layout guidelines from the manufacturers. While this is the best practice, Layout engineer and in fact the design engineer should keep in mind that, the PCB Layout guidelines and evaluation board design from manufacturers is under ideal conditions where there is no circuit around and a lot of room to play around. Our modern designs are dense and complex, so, only a portion of such guidelines can be practical and trade offs must be done for the remaining guidelines
• PCB Layout engineers must keep a close track on the thermal considerations of the board. The amount of copper to be provided, for the heat to be dissipated across the PCB is a critical consideration. This point is a design consideration which the PCB design engineers have to bring our of their experience
• Especially, for the high speed designs, it is important that PCB layout engineer works on pre and post layout simulations by himself giving him a clear view of what need to be done in the PCB Layout.
• While creating a PCB footprint for the components, PCB designers must make a practice of entering the height parameter. This helps while there is need to generate mechanical models to check the compatibility
• Most of the PCB engineers do not bother about the board testing. It is good for the layout engineer to get to now what has worked and what didn't. Especially, in the high speed designs while probing it is must they involve and get to know the drawbacks of the design

While there are many other points that can be mentioned, these are some basic observations. Please, feel free to give your comments.