FreeLists / si-list / [SI-LIST] Re: DDR2 IMPEDANCE

["john lipsius" <hreidmarkailen@xxxxxxxxx>]

54 - 66 ohms for jedec std RDIMM application:
Ref. 3 below:
JEDEC Standard No. 21C
Page 4.20.10-87

There are other applications.  See ref. 1.

References:

1.      Jedec design files by Elpida (non-VLP 240-pin ddr2 RDIMM)

*http://www.jedec.org/download/DesignFiles/*   for selections*
http://www.jedec.org/download/DesignFiles/DDR2/PC2-5300_RDIMM_V310_RC_P0_20050221.zip
*

2.      DDR2 RDIMM typical datasheet (should have internal copy of Ref 4
below):

*
http://download.micron.com/pdf/datasheets/modules/ddr2/HTF18C64_128_256x72G.pdf
*

3.      Jedec: PC2-3200/PC2-4200/PC2-5300/PC2-6400 DDR2 SDRAM Registered
DIMM Design Specification

Revision 3.2 Oct 04 2005 Release No. 15

main page *http://www.jedec.org/download/search/*    Search "jesd21-c";
select all of  document;

link is under: MODULE4_20_10 : *
http://www.jedec.org/download/search/4_20_10R15.pdf*

4.      JEDEC Spec:  SSTL 1.8V. Input/output signal spec. for ddr2.
http://www.jedec.org/download/search/JESD8-15a.pdf


**

   - *From*: "tao xu" <helen.tao.xu@xxxxxxxxx>
   - *To*: jory_mckinley@xxxxxxxxx
   - *Date*: Fri, 1 Dec 2006 23:07:26 +0800

 for trace impedance. it is normally 50 or 60 ohm based on my previous
experince. Clock singal sometimes has lower impedance trace than other
signal groups.

On 12/1/06, tao xu <helen.tao.xu@xxxxxxxxx> wrote:
> kenny, what kind of impedance did you ask? Buffer output impedance for
> interface or normal trace impedance on board?
>
> On 12/1/06, Jory McKinley <jory_mckinley@xxxxxxxxx> wrote:
> > Hello Kenny,
> > Are you designing this type interface?  If so then take a look at the AMCC
> > spec:
> > https://www.amcc.com/MyAMCC/retrieveDocument/PowerPC/440EP/PPC440EP_DS2002_v1_24.pdf
> >
> > There should be some board guideline information for the DDR interface.
> > You will have to simulate.
> >
> > Simulating an existing interface?  If you can obtain a board file then the
> > traces (impedances) can be extracted for the interface.
> >
> > -Jory
> >
> >
> >  Kenny Frohlich <kenny_frohlich@xxxxxxxxx> wrote: Hi All,
> > Can someone please tell me where I can find information on DDR2 impedances
> > (ie. what is the impedance of CLK? Data? Address? Command?)?
> > We use PowerPC PPC440EP and on-board DDR2 SDRAMs.
> >  Thank you.
> >
> >  Regards,
> > Kenny


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