From customer sketches we can produce a Project File. This contains generating schematics from our libraries. Each component symbol will have a description of that component, a supplier, stock code and a special notes column. At the press of a button an Excel parts list is created listing every component within the design. After the schematic has been approved by the customer the next step is to translate to PCB for layout. The benefit of covering a new design in this way it that the total makeup is contained in one place.
It is also possible using parts lists and schematics supplied by the customer to go straight to layout. Components placed from library can be connected as shown in the schematic using connections traces. When the layout is complete a net list is then supplied for sign off.
This is an area where requirements have changed a lot over the past few years. Impedance control for differential and single end data lines, mostly in the regions of 50 or 75 ohms had led to more consideration as far as track widths, where they are placed be it on external or internal layers. We have the front-end software to calculate these factors. We can also follow the manufacturing cycle through our factory and when requested provide test coupons proving these impedance factors have been achieved.
Although they have been around for sometime they are still not widely used. They are very useful for connecting rigid pcb’s in a stacks. Interlinking from say the main microprocessor to a moving head interface board because of their flexibility. The layout considerations are quite different from that if rigids. Careful thought is required for cover lays to make sure you have soldering point widows in just the right places. They may also need rigid areas at specific points to create flatness for say the placements of smd components. These rigid areas can be made up from additional layers of polyimide of in fact thin layers of rigid material.