Double Data Rate (DDR3) Shouldn't be Double Trouble - Part 1
There's a lot of talk about the 3rd generation of Double Data Rate memory known as DDR3. We at Nine Dot Connects have laid out several DDR3 boards in the past three months. There is quite a bit of detail to know about DDR3 design and layout, and unfortunately, there is also a lot of misinformation out there. We have waded through and analyzed the literature. We wish to share our findings and understanding with you.
Our two-part series on this topic will first cover key concepts necessary for proper signal integrity and general DDR3 design. Topics to be covered this month are:
Brief history of the DDR concept
Comparison between the different generations of DDR
The signaling and timing requirements for DDR3
Understanding match length versus match delay
Compensating for typical routing delay
Using the iCD Stackup Planner to assist in delay matching calculation
In part 2, we will build upon this foundation by demonstrating DDR3 layout techniques' practical aspects.