[SI-LIST] Re: AW: AW: Fiber weave effect modeling
- From: "Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>
- To: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Fri, 14 Jan 2011 09:27:56 -0800
Bert,
The latest Isola data shows these glass weaves in all of their resin
systems. Not sure about Nelco as they haven't updated their materials info
in about 5 years.
--------------------------------------------------
From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
Sent: Friday, January 14, 2011 12:34 AM
To: "Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Subject: AW: [SI-LIST] AW: Fiber weave effect modeling
> Hi Lee,
>
> this is really interesting. I knew that the 2113 is quite uniform as is
> uses thin glass filaments, but I've never heard of the other glass styles.
> I just checked with ISOLA and NELCO low loss materials, and couldn find
> the other types either. Could it be they are only used for lossy FR4 Type
> of materials, or just by certain vendors?
>
> BR
> Gert
>
>
> --------------------------------------------------------------------------
> Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft:
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> persönlich haftende Gesellschafterin: HARTING Electronics Management GmbH;
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> 8808; Geschäftsführer: Edgar-Peter Duening, Torsten Ratzmann, Dr.
> Alexander Rost
> -----Ursprüngliche Nachricht-----
>
> Von: Lee Ritchey [mailto:leeritchey@xxxxxxxxxxxxx]
> Gesendet: Donnerstag, 13. Januar 2011 19:22
> An: Havermann, Gert; si-list@xxxxxxxxxxxxx
> Betreff: Re: [SI-LIST] AW: Fiber weave effect modeling
>
> I recommend you use neither of those weaves with high speed serial links
> due to there negative effect on skew. The best weaves are known as "flat"
> weaves. The best are 1067 (replaces 106), 1086 (replaces 1080), 2113 and
> 3313. These are so uniform you don't need to worry about weave effects.
> These weaves were developed to make laser drilling blind vias more uniform
> and happen to be great for SI purposes!
>
> You also don't need to route your PCBs on a 15 degree angle to the weaves,
> which is painful to do and wastes materials, so long as you stick with the
> weaves listed above.
>
> Lee Ritchey
>
> --------------------------------------------------
> From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
> Sent: Wednesday, January 12, 2011 6:31 AM
> To: <si-list@xxxxxxxxxxxxx>
> Subject: [SI-LIST] AW: Fiber weave effect modeling
>
>> this is a great paper, many thanks for sharing it with the si-list.
>>
>> please allow me a question. I understand that the 106 and 7628
>> Prepregs are used to predict the dk values of "pure epoxy" and "close
>> proximity to the Glass bundle".
>> Do you think that the "pure epoxy" value is always the worst case that
>> I have to expect for my diff pair? If I (for instance) would only use
>> 7628 Style everywhere, will there even be areas "in pure epoxy", or is
>> the weave dense enough that the worst dk is somewhere between the
>> calculated min. and max. value?
>>
>> BR
>> Gert
>>
>>
>> ----------------------------------------------------------------------
>> ---- Absender ist HARTING Electronics GmbH & Co. KG; Sitz der
>> Gesellschaft:
>> Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596;
>> persönlich haftende Gesellschafterin: HARTING Electronics Management
>> GmbH; Sitz der Komplementär-GmbH: Espelkamp; Registergericht der
>> Komplementär-GmbH: Bad Oeynhausen; Register-Nr. der Komplementär-GmbH:
>> HRB 8808; Geschäftsführer: Edgar-Peter Duening, Torsten Ratzmann, Dr.
>> Alexander Rost
>> -----Ursprüngliche Nachricht-----
>>
>> Von: si-list-bounce@xxxxxxxxxxxxx
>> [mailto:si-list-bounce@xxxxxxxxxxxxx] Im Auftrag von Bert Simonovich
>> Gesendet: Freitag, 7. Januar 2011 21:55
>> An: si-list@xxxxxxxxxxxxx
>> Betreff: [SI-LIST] Fiber weave effect modeling
>>
>> Hi all,
>>
>> Recently there were discussions on PCB fiber weave effect. I recently
>> did a study and published a White Paper titled, "Practical Fiber Weave
>> Effect Modeling".
>>
>> Abstract:
>> Fiber weave effect is becoming more of an issue as bit rates continue
>> to sore upwards to 5GB/s and beyond. Due to the non-homogenous nature
>> of printed circuit board laminates, the fiberglass weave pattern
>> causes signals to propagate at different speeds within differential
>> pair traces; causing timing skew and mode conversion at the receiver;
>> leading to reduced bit-error-rate (BER) performance; and increased EMI
>> radiation. The relative dielectric constant (Dk) surrounding a trace
>> ultimately determines its propagation delay. This paper delves into
>> the issue and presents a novel approach to practically establish worst
>> case min/max values for Dk and use them to model this effect using ADS
>> circuit modeling software. A PCIe CEM
>> Rev2 case study is used to practically demonstrate the model and to
>> explore the design space.
>>
>> Here is the link: http://lamsimenterprises.com/White_Papers.html
>>
>> Thanks to Jeff Loyer, Istvan Novak and Gustavo Blando for there help
>> in clarifying some results of their prior published work on the subject.
>>
>> I hope you find it useful.
>>
>> -Bert
>>
>> Lambert (Bert) Simonovich
>> Consultant and Founder
>> LAMSIM Enterprises Inc.
>> Web Site: http://lamsimenterprises.com
>> Blog: http://blog.lamsimenterprises.com/
>>
>>
>>
>>
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