Rockchip RK32 Series, Hardware Design Manual

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RK3288 Hardware Design Guide

Main components(CUP,DDR) and signal traces are mainly placed on TOP or BOTTOM
layer;

Small components like filter capacitor are mainly placed on TOP or BOTTOM layer; big
components can be placed on these two layers as well if structure is allowed.

Shielding:

Shielding case is necessary on TOP layer of PCB to suppress EMI and improve the
reliability of product, it also works as a heat sink of CPU to improve heat
dissipation effect.

If space is allowed, reserve a shielding case space on BOTTOM layer as well, or
reserve a big GND area with solder mask for shielding of coordination structure.

Copper integrity
：
Integrity and continuity of copper under CPU can guarantee the
signal return path, improve signal transmission quality and stability of product as well
as strengthen heat dissipation performance of copper, as shown in below Fig. Please
follow below recommendations to ensure integrity and continuity of copper and
improve performance of product,
Fig 3-2

Set copper layer as split/mixed;

The clearance between the via and the copper is 5.5mils;