Optimum Design Associates Blog

The silkscreen is a helpful tool in identifying components on the board. During PCB layout it should be designed for a consistent flow that allows easy identification of parts while using a minimum of leaders in difficult areas. Special care should be taken to ensure that each device has its appropriate associated markings, such as polarity, pin #1 location, 10th pin marker for fine pitch parts, or connector pinouts. Some parts may require additional labeling that should be specified by the customer. This may include labeling connectors, LEDs, switches, high voltage areas, or critical circuits (see the figure below).

Engineering managers tasked with outourcing PCB layout face a daunting challenge: comparing the total cost of multiple layout quotes.  Truth is, we don't know the answer either, but here's why it's so challenging.

Determining a price for PCB layout services is conceptually simple:  Estimated number of hours times an hourly rate.  The trick is estimating how much time, and which rate is applicable. Over the past 24 years we've quoted more than 6,000 designs and evolved a pricing methodology that uses a structured process applied to a baseline formula which is then modified to accommodate exceptional items. 

Part of a designer's professional developments should be to learn as much as possible about the activities that go before and come after the layout process. And with today's highly complex designs, the assembly process has grown in importance and has become a major concern for designers. 

Integration is the process of adding intelligence to the PCB database by means of a netlist or schematic. This can only occur once all of the necessary library elements for a particular design have been created by a design bureau or by receiving a customer-supplied library. A 100% successful design integration (no errors) will allow the designer to confidently place components, route, and output manufacturing files with the PCB database and schematic in sync. The engineer may supply the data for integration in one of two ways: schematic or netlist.

The placement of bypass capacitors is one of the most critical phases of the design process. Failure to place them correctly can completely negate their performance. Also critical is a situation in which there are too few capacitors for particular components. This information should be communicated back to the engineer, whenever it occurs, so that the schematic can be updated.

Knowing how to place a bypass capacitor is a crucial step in PCB design. In most cases, we recommend that the bypass capacitor is placed on the bottom side for ideal proximity to an SMT, all while utilizing extra space. But bypassing BGAs can be slightly trickier. BGAs are high desity components with high pin counts, and it's generally harder to acheive the desired proximity. 

Deciding to outsource a PCB design can be a daunting task. Between choosing a design firm to handle the design, knowing what to give them in terms of inputs, ensuring the design meets your specifications, there are myriad opportunities for a problem to arise. Upon deciding who you will be outsourcing the design too, the creation process begins. There are a number of critical steps which must be met for successful completion of a design. Here we’ll try and provide insight to the design process, as well as what is required of both the customer and designer at major milestones within the process.

 Design Process Stages

• Initial Design Review & Integration
• Mechanical Definition
• Placement & Review
• Routing
• Pre-Delivery Review
• Wrap-Up

A fabrication drawing specifies how the PCB is to be manufactured. There are four major sections to a fabrication drawing—Board Illustration, Drill Chart, Section A-A, Notes, and Title Block. 

Originally developed by Valor, ODB++ is an electronic database for printed circuit board manufacturing. Created in 1995, it was designed as a way to better organize the transfer of board data from the designer to the manufacturer.