AN2826 Freescale Semiconductor / Motorola, AN2826 Datasheet - Page 9

• Manufacturer Part Number: AN2826
• Description: DDR-SDRAM Layout Considerations for MCF547x/8x Processors
• Manufacturer: Freescale Semiconductor / Motorola

MCF547x/8x Validation Board DDR Layout
The majority of the signal routing on this PCB was kept to the top and bottom layers to allow access to
these signals in case they required modification. On a production system many of these signals could be
routed on the inner layers of the board close to the ground plane to minimize noise, as suggested above.
The track and space tolerances used on the board were a minimum of 6 thousandths of an inch. There was
no variation of track width, which should be avoided because it can cause signal reflections. The PCB is
constructed using FR4 material.
3
MCF547x/8x Validation Board DDR Layout
The following diagrams are taken from the MCF547x/8x validation board layout files. These files are
available on the Freescale ColdFire website: http://www.freescale.com/coldfire. They are Gerber format
files that show the whole PCB rather than concentrating on the connection between MPU and DDR
SDRAM, as shown in the following diagrams.
DDR-SDRAM Layout Considerations for MCF547x/8x Processors, Rev. 1
Freescale Semiconductor
9