The effective use of power planes is an essential part of modern PCB design. They appear as low-impedance paths for signals and are used to reduce noise in the circuit, particularly for the common signal. In a multilayer PCB, one or more of the layers is normally dedicated to a plane. The Proteus Design Suite fully supports plane layers, user defined planes and split planes. All power planes are automatically drawn compliant with the design rules for the board and both fill style and pad connections are user configurable.
Power or ground planes can cover an entire layer or be constrained to a user defined area on a layer. On a multi-layer board it's common to have dedicated layers consisting of only planes and in Proteus these are set up as plane layers in the layer stackup. Users can set full layer coverage on layers with tracking via a simple dialogue form and the copper will automatically step away from all pads and tracking.
Meanwhile, for split planes a dedicated zone mode allows users to draw out the area in which they need copper coverage. Multiple split planes can be placed on a layer or a split plane can be placed inside a full layer plane with the requisite clearances being automatically generated.
You can place a flood fill with all PCB packages but the ability to place multiple power planes per layer is part of the advanced feature set and requires Proteus PCB Level 2 or higher.
The clearances between the power plane and other objects is the larger of the relevant design rule and the default clearance entered in the plane configuration dialogue form. This gives the user total control as they can override the default clearance for the plane with a design rule room in a particular area.
Default connection type for pads on the same net (thermal, solid, etc.) are set globally for the plane and can then be overridden on a per pad basis where needed.
Normally power planes are drawn simply as a solid copper flow in the defined area. However, if needed a user can specify a hatch or a diagonal hatch along with a step value to control granularity. Hole openings for pads default to octagonal but can be changed to circular for use with hatched planes.
You can also set a plane fill type to be empty which then forms a keepout area on the layer. This is often used where one plane floods the layer and an area inside the plane wants to be excluded from the copper pour.
The ability to draw split planes or create keepout areas (empty zones) requires Proteus PCB Level 2 or higher.
Via stitching is a technique used to tie together larger copper areas on different layers with lots of vias, helping keep return paths short and to reduce noise on the PCB. A via shield or picket fence is a single row of via's around the perimeter of power planes or bracketing one or more routes. These can help prevent electromagnetic interference with other equipment or help isolate signals on the PCB operating at different frequencies.
Automatic stitching of zones and via shielding of zones are fully supported in Proteus and can be added directly from the right click context menu.