Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

[BP] Eye On Return Loss

Richard and Adam

unfortunately with my flight delayed I won't make it to your 
presentation.  But I have the following comments.

    o. The original BP return loss spec came from OIF and started from 
XFP work.  When you specify
    return loss of 8 - 16.6 LOG10(f/7.5) is measured at the package 
balls in to the device including
    any wirebond, ESD, etc.  So you should not add additional ESD cap to 
this model.  In XFP we created
    a compliance package by using 4 sections of RLC.  The only drawback 
of this type of model which is
    similar to what you have created is that at high frequency does not 
behave like a well design package as
    the return loss goes going zero.

    o. I have looked at your cap like and Ind like package model with 
0.415 pf differentially for ESD cap
    please see attach, just ignore the mask line called Spec on these 
graph.  As these graphs show the proposed
    package model will add significant penalty to the channel due to 
their resonances:
       - The Ind Like has about 10 dB loss at 10.5 GHz
       - The Cap Like has about 5 dB at 7.5 GHz

Here is suggestions:
     create multi-section RLC compliance package/ESD
     or start with more realistic package model then add ESD cap

Thanks,
Ali

GIF image

GIF image

begin:vcard
fn:Ali Ghiasi
n:Ghiasi;Ali
org:Broadcom
adr;dom:;;3151 Zanker Road;San Jose;CA;95134
email;internet:aghiasi@broadcom.com
title:Chief Architect
tel;work:(408)922-7423
tel;cell:(949)290-8103
url:http://www.broadcom.com
version:2.1
end:vcard