For the layout of DDR3, we first need to confirm whether the chip supports fly-over topology to determine whether we use T topology or fly-over topology.

Generally, our DDR3 layout can meet the following basic design requirements:

1. Considering the maintainability of BGA, the peripheral devices of BGA are 5MM, and the minimum is 3 mm.

2.DFM reliability: according to the relevant process requirements, the spacing requirements of DFM are met between devices during layout; And consider the aesthetics of element placement.

3. Whether the absolute equal length meets the requirements and whether the relative length is easy to realize: it is necessary to confirm the length limit and timing requirements during lofting to leave enough space for winding equal length.

4. The position of filter capacitor and pull-up resistor, etc. Filter capacitors are placed close to each pin, and energy storage capacitors are evenly placed around the chip (on the power layer path); Pull-up resistors are placed as required (wiring length is less than 500mil).

Note: If a demo board or chip manual is provided, please follow the requirements of the demo board or chip manual.

This paper explains the rules and precautions of DDR3 layout in detail.

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