Information It's important to have everything necessary to make the perfect PCB Layout. A good engineer would foresee any complications that may crop up; problems with sourcing datasheets, lack of available space on the design to avoid manufacturing headaches. Three types of information are crucial for a successful PCB design. DXF or mechanical drawing, BOM (parts list) and a schematic. A layout guide provided by the design engineer and necessary reference designs is also useful for a successful PCB layout. Mechanics Today's PCB designs are very complicated with limited space. Some projects may involve multiple layouts fitted together in a box. The best way to ensure the PCBs fitted together correctly without complications is with a CAD package such as solid works. The PCB design import the CAD drawings. This saves a lot of time, we place the parts on the imported locations. This is the most accurate and cost-effective way of placing components in specified areas.   Design Rules This is a crucial stage and makes up the backbone of any PCB layout. Accurate placement is essential, there could be major flaws with the functionality of the circuit board. The rules basically control any clearance and track thickness on the design. For more complicated layouts; rules for impedance controlled signals, extra clearances for noisy tracks, implementation for relative propagation delays and constraint regions are necessary.   Component stage It is crucial to start and maintain a parts library during the PCB layout stage. Most of the PCB design errors come from incorrect footprints. Using a standard footprint name such as IPC can help design engineers and colleagues select the correct part without recreating the same footprint over again. Part generators are useful tools to create parts. Entering part sizes into the generator,  the software calculates the optimum size for pads, including the paste (reducing this by 30% to prevent excessive solder shorting pads together). Other useful information such as component and placement outlines, component heights and keepouts simplify and aid the PCB layout. All components must be double checked before added to the library and updating the PCB design. Time and money's saved when using a library with reliable components. Placement stage Each PCB layout is unique, there are many questions that are asked to make sure the design meets the customer or engineer's needs. Failing to resolve these queries, could end up with the placement reworked multiple times. Is there…

When using components such as switch mode power supplies (SMPS), the PCB layout is critical. Faults in the PCB layout cause a number of problems including switching jitter.  Poor output voltage regulation and possible failure with the PCB design. Issues like this can be avoided, saving money and time on scrapped circuit boards and PCB modifications.   Datasheets When putting together a PCB layout the best approach is to review datasheets for devices such as SMPS. A respectable manufacturer such as Texas Instruments will offer guidelines and reference designs to follow for your PCB layout. Usually a layout guide will show a PCB design with all of the parts, copper tracks and vias arranged for an optimum performance. It will show lots of space with no other components interfering. This does not happen in the real world, most of the time there is not enough room to keep parts and tracks away from critical areas. The best way is to follow the guide and bend the rules only when it's absolutely necessary to do so. Below is a part of the schematic that show the SMPS and the related components. The second diagram is the recommended PCB layout from the manufacturer.   Layout Guide The decoupling caps (input and output) must be close to the regulator. The most important aspect of SMPS is to reduce high current loops. The recommended layout shows a GND plane under the component, flooding over other components connecting to GND. There is also a skinny blue line representing a track on the bottom side of the board.  This is the feedback signal, the track is on the bottom side to reduce interference and must not be in the high current path. The PCB layout must follow this guide for it to function correctly. Here is the schematic and PCB layout to highlight the key areas, orange for input, purple for output and burgundy is feedback.   Comparison The PCB layout shows the input signal running from a plane (using vias) through the decoupling caps through the inductor and into the module (REG1 highlighted in yellow) via more caps. The output signal runs through decoupling caps and away through the inductor. The GND signals connect to the GND plane through vias at the module and at the decoupling caps. The burgundy feedback signal is routed from pin 4 of the module, through the resistor and capacitor…