66AK2H14: DDR3 Interface Design

joe lindula

Part Number: 66AK2H14

Hello, I am interfacing DDR3 to an 66AK2H14 ARM+DSP and I'm looking over the SPRABI1C DDR3 Design Requirements for Keystone Devices page 22 Table 15. I am not familiar with Stub Skew what is exactly is that and what are the units? Table 15 does not show any units but Tables 11-12 show the units "mils"..

www.ti.com/.../sprabi1c.pdf

Thank you,
Joe

over 7 years ago

0 Yordan Kovachev over 7 years ago

TI__Guru**** 161600 points

Hi Joe,

A stub or resonant stub is a length of transmission line or waveguide that is connected at one end only. The free end of the stub is either left open-circuit or (always in the case of waveguides) short-circuited.
A skew in general is a time difference between signals: www.ti.com/.../slyt179.pdf

So a stub is measured in mils, a skew is measured typically in seconds (ps or ns).. However, because skews are compensated with PCB trace length it is given in mils in table 15.

Best Regards,
Yordan

0 joe lindula over 7 years ago in reply to Yordan Kovachev

Mastermind 6940 points

Thanks Yordan!@

Processors

Processors forum

66AK2H14: DDR3 Interface Design