Foreword
About layout: As allegro layout method, we are schematics marquee, marquee circuit module obtained in the pcb, then the layout. But allegro directly to this concept of direct cross-mode free. CROSS allegro is achieved in: simultaneously opened orcad and pcb editor, directly in orcad schematic marquee, the marquee device directly in the pcb editor.
You can refer to the idea of the layout series "four-layer circuit board design", without repeated here.
Import differential pair
Click on logic -> assign differential pair. The following pop-up screen.
Followed by the click of a differential pair of two pins with the left mouse button, such as A24, B24, you can see these two pins are added to the net1 and net2 inside; then click on add, has become a set of differential pairs.
The cascading management
This is going to do the four-layer board, the relevant principles of the concept of four-layer board also can refer to my previous article series.
Posted links: four-layer PCB board production 3-- laminated core management .
Here they talk about the operation.
Click setup -> section editor, the pop-up screen:
as shown above, the laminate Allegro than AD manager for a number of simple, there is only the concept of plies (inner layer, an insulating layer, plate, and the wiring layer). Such a 2 ply, only a two layer and the intermediate layer, and a solder resist screen surface such directly counted.
Right-click on the TOP , select add layer below. Continuously adding four plies. The reason for adding four plies as shown in FIG.
After adding up all plies in accordance with the principle of "barrier layer" of the intermediate layer renamed, the second layer is a bottom layer, the third layer is a power layer.
Finally, the layer of the property to plane, meaning within the layer.
Click apply to applications.
