With the increased complexity of devices they carry , PCB design has become increasingly complex. For quite a long time, circuit design engineers have been no problem to carry out their own independent design, and then transferred to the completed schematic design PCB design engineers , PCB design engineers complete their work after independence , the Gerber files for PCB manufacturing sub- plant. Circuit design engineers , PCB design engineers and PCB manufacturing jobs are isolated from each other , little communication.
With the use of large BGA package applications growing popularity of programmable devices , and high -density interconnect (HDI), the timing of the key differential signaling widely used, now and then using such an isolated way PCB design will bring catastrophic consequences, and the parallel development process allows multiple simultaneous development process to help ensure the success of the design , to avoid delay , overhead and rework. This article summarizes the key criteria for the various stages of parallel PCB design .
PCB design is the first step in the conceptual stage. In this case , the circuit design engineer should be made with a PCB design engineer technology assessment. This assessment should consider such questions:
1 using what device ?
2 Which devices use the package ? Pin count how many ? Pin Configuration How ?
3 based on cost and performance trade-offs , using layers PCB?
4 What is the target clock frequency and signaling speed and other parameters are ?
In addition , the design engineer should consider bus architecture , is the use of parallel or serial connection factor , as well as impedance matching strategy. Reflection , ringing and other undesirable interference occurs when the impedance mismatch.
Work
These considerations made a successful PCB design PCB design is a key issue is communication, because the PCB design is no longer a man's job, but teamwork between engineers of different groups. Communicate this theme throughout the PCB design process always , circuit design team must clearly communicate the design intent and PCB design team , they must also understand the PCB design tools can do, can not do what the premise clearly involved in the process.
With the increasing complexity of the PCB routing , the increasing rate of the signal , the PCB design coordinated manner than traditional serial flow better results ( Figure 1 ) . Will research and select components from the rest of the entire design process to isolate , as well as the schematic entry, simulation and layout stages have been a common practice in independent . Therefore, the design engineer to select the best tools to facilitate the sharing of data and processes , this is the only way in different parts of the design team can take advantage of parallel and shorten the design cycle.
Figure 1 : length (a) traditional PCB design cycle serial development process , information sharing is limited, while costs continue to rise ;
(b) the development of a parallel development process allows multiple processes simultaneously, to help ensure the success of the design , to avoid delay , overhead and rework
Design Create
In the design creation phase , engineers will ultimately determine a good device and to generate a variety of databases, which in turn has accelerated the schematic entry . At this stage, the design engineers to evaluate and select the building blocks , and you can visit the manufacturer's Web site and search data sheet specifications . A better way to accomplish this task is to select the device directly in the schematic entry process. By this way to achieve schematic entry, this process can be used as a test method .
