[SI-LIST] Re: DDR2 IMPEDANCE
- From: "john lipsius" <hreidmarkailen@xxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Thu, 7 Dec 2006 18:05:46 -0800
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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