[SI-LIST] Re: trace impedance difference in same signal group of Intel guide
- From: "Powell, Jon N" <jon.n.powell@xxxxxxxxx>
- To: Aubrey Sparkman <asparky@xxxxxxxxxxxxxxxxxxxxxxxx>, "'Grasso, Charles'" <Charles.Grasso@xxxxxxxxxxxx>, 'fei xue' <harrison_cls@xxxxxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Thu, 6 May 2010 09:05:20 -0700
Are these channels expected to be routed on different layers?
Like is CHA on Microstrip and CHB on Stripline?
Jon Powell
EPSD Product SI
DISCLAIMER:
Though I work for Intel, I am not a spokesperson for Intel nor is this an
official communication.
The opinions stated are my own and not necessarily that of Intel.
將
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Aubrey Sparkman
Sent: Thursday, May 06, 2010 7:48 AM
To: 'Grasso, Charles'; 'fei xue'; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: trace impedance difference in same signal group of Intel
guide
Harrison,
IF your company is large enough to be supported by Intel, you must ask
yourself whether you value their support. If you do, you will follow their
guidelines. If not, you are free to develop your own guidelines.
Aubrey Sparkman
512-461-6165
asparky@xxxxxxxxxxxxxxxxxxxxxxxx
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Grasso, Charles
Sent: Thursday, May 06, 2010 8:26 AM
To: fei xue; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: trace impedance difference in same signal group of
Intel guide
I'd ask Intel. Looking at the numbers theres not a whole lot of difference
between a 37ohm -15% trace and a 28ohm +10% trace. These specs look a
little strange! Anyone from Intel on the line??
________________________________________
From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] On Behalf
Of fei xue [harrison_cls@xxxxxxxxxxxx]
Sent: Wednesday, May 05, 2010 1:12 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] trace impedance difference in same signal group of Intel
guide
Hello all,
May I raise a question to all of you, as you know, Intel does more
constraints restrictions than any other semiconductor vendor especially in
MCH platform design guide (PDG). For example, in DDR2 control group signal
constraints (CKE, CS and ODT signals) of Intel Bigby 3210 MCH chipset, the
characteristic trace impedance of the DDR2 control group signals from MCH to
Channel A dimms is 37Ohm+/-15%, however the characteristic trace impedance
from MCH to Channel B dimms is 28Ohm+/-10%. The traces of Channel B dimms
are longer than Channel A dimms. My question are,
1, why is the trace characteristic trace impedance of Channel A dimms
different from impedance of Channel B dimms.
2, I checked the IBIS model, the output buffer model of Channel A dimms is
the same as model of Channel B dimms, they are 38.9Ohm (I got this from IBIS
VI curves), so it is not the reason of buffer output impedance.
3, I do not think the trace impedance's difference is because of trace
distance difference between Channnel A and Channel B, 37Ohm and 28Ohm are
big gaps.
4, PCB manufactory gave us feedback that they can not control trace
impedance within 28Ohm+/-10%, what they can do is controlling impedance
within 28Ohm+/-5Ohm, how to evaluate this impact? can we confirm with
manufactory that controlling impedance within 28Ohm+/-5Ohm is ok or not.
I appreciate if you have any hints on this.
Harrison
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu---------------------------------------------------
---------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
