1 Drawing principle diagram
(1)Open the Protel SE 99 software, the establishment of the database and name, but need to pay attention to suffix.Ddb, the command from the menu and click on File/New, from the open "New Document" dialog box, select the principle map icon, double-click the icon of new principle diagram design documents, according to the actual requirement of the design of the document name, double-click the renamed the document can be directly carried out principle diagram design.
(2)Reasonable arrangement of schematic design environment. Design the specifications of the drawings according to the menu commands design / options and tools / preferences.
(3)It is loaded in the original original file library. In the design of file manager to browse the principle diagram of the browser interface, browse library drop-down list, and then click Add / delete button in the pop-up change for the component library file list dialog box 99 SE sub directory, select the synchronization channel path in this directory, in the component library list, select the desired component library.
(4)Based on the actual circuit needs, we find the original components, then the single device manager button, and set up the package, attributes and quantities reasonably through the Tab key, and make reasonable adjustments to the boundary based on the component elements.
Using Protel 99 SE, all kinds of tools are provided to illustrate the symbolic meaning of line connection, work plane and electrical wiring connection, symbol connection, and form a complete circuit diagram principle.
(6)Conduct electrical rules inspection
By using the computer aided design of the Protel 99 SE appliance rules, click the Tools/ERC command in the menu, and design the circuit schematic of the electrical rules check. If some errors occur, it is necessary to correct the error according to the specific circumstances of the error and correct it to the correct point.
(7)Generating element table
Select the Reports/Bill of Material menu to produce the element table.
(8)Create a network table
The schematic diagram of bridge circuit design between network tables and PCB, the "design" command in the execution menu, can produce the relationship between device components encapsulation, component name, parameters and components connected to the network table.
2 Creating component packaging
The implementation of the menu command File/New, select the original path chart, from the open New Document dialog box, double-click the icon, a component design package design documents, and named the "OTL power amplifier circuit". Double click the document icon to make circuit encapsulation according to the actual components.
3 Draw PCB
（1）Restore the PCB design document
（2）Planning circuit board
（4）Loading component package library
（5）Load network table
（8）The designer himself changed