This “loop closure” prevents a layout from going too far astray and will minimize reworking the board layout. Give the designer interim completion points-at which you want to be notified of the layout progress for a quick review.
The more information you can provide, and the more involved you are throughout the layout process, the better the board will turn out. Your inputs and guidance are most critical at the beginning of the layout process. An ounce of prevention at this point is worth more than a pound of cure! Don’t expect the layout person to be able to read your mind. If you’re not doing your own layout, be sure to set aside ample time to go through the design with the layout person. What kind of information belongs on a schematic besides the usual reference designators, power dissipations, and tolerances? Here are a few suggestions that can turn an ordinary schematic into a superschematic! Add waveforms, mechanical information about the housing or enclosure, trace lengths, keep-out areas designate which components need to be on top of the board include tuning information, component value ranges, thermal information, controlled impedance lines, notes, brief circuit operating descriptions … (and the list goes on). The designers, technicians, and engineers who will work on this job will be most appreciative, including us at times we are asked by customers to help with a circuit because the designer is no longer there. Put as much useful information on the schematic as possible. A schematic that has a natural and steady flow from left to right will tend to have a good flow on the board as well. Be thoughtful and generous when drawing a schematic, and think about signal flow through the circuit. The SchematicĪlthough there is no guarantee, a good layout starts with a good schematic.
Thinking ahead and paying attention to salient details throughout the layout process will help ensure that the circuit performs as expected. A high-performance circuit design that looks good “on paper” can render mediocre performance when hampered by a careless or sloppy layout. When op amps operate at high RF frequencies, circuit performance is heavily dependent on the board layout. Not every topic can be covered in detail in the space available here, but we address key areas that can have the greatest payoff in improving circuit performance, reducing design time, and minimizing time-consuming revisions.Īlthough the focus is on circuits involving high-speed op amps, the topics and techniques discussed here are generally applicable to layout of most other high-speed analog circuits.
But it is also intended as a refresher to benefit those who have been away from board layout for a while. A major aim is to help sensitize newcomers to the many and various considerations they need to address when designing board layouts for high-speed circuitry. This article addresses high-speed layout from a practical perspective. There are many aspects to high-speed PCB layout volumes have been written on the subject. A Practical Guide to High-Speed Printed-Circuit-Board Layoutĭespite its critical nature in high-speed circuitry, printed-circuit-board (PCB) layout is often one of the last steps in the design process.
0 kommentar(er)
