DDR3 Routing - Simplified Part 1

Have you been led to believe that High Speed matched length routing in Altium is difficult ?

Routing DDR3 can be simplified in Altium provided you apply a few clever tricks and use a couple of scripts.

The scripts were created by Petar Perisin and can be downloaded at Altium Designer addons

Two of Petar's scripts are key to simplifying DDR3 routing.

Download Links:

Length Tuning Helper v1.0

Select Bad Connections v1.5

Length Tuning Helper 

Length Tuning Helper is simple to use and is an example of ingenuity.  This script solves the problem of creating matched length signals for designs which need to account for IC package pin delays.

The script can import Xilinx *.pkg or *.csv files.

I really appreciate the *.csv file option. 

The script also has an option for the units.

*.csv format example:

Units;mil

C3;563.55

B3;633.97

A2;558.13

A4;677.25

D3;567.52

In Excel the Pin Names and Pin Delay lengths are separated by a semi-colon in the same cell in column 'A' and the file is saved in the *.csv format.

Using the script is a simple four step process.  With *.PcbDoc selected in Altium run the script and . . .

1. Select your DDR3 IC reference designator from a drop down menu. 
2. Select Open File to browse and select the *.pkg or *.csv file.
3. Select a Net Class from a drop down menu.
4. Select OK

The script will add tracks above the design which are equal in length to the pkg pin delay data.

Here is an example of 32 data bits including DQSx and DMx signals

These track segments have been assigned the appropriate net names.

Now, the only thing left to do is to route the data lanes to the matched length requirements.

Once the routes have been matched you can delete these temporary track segments.


Thank you Petar ! ! ! 


Tip: Save these temporary tracks in a *.pcbdoc and add this *.pcbdoc to your project, then you can copy and paste these tracks back in to the design as needed. 

Use Edit > Paste Special to preserve the net names when copying the tracks.

In DDR3 Routing - Simplified Part 2 I will demonstrate why you should use Petar's 'Select Bad Connections' script.