[SI-LIST] Re: RE：How can we get the resonance frequency and Q between
- From: steve weir <weirsi@xxxxxxxxxx>
- To: luping liu <liewluping@xxxxxxxxxxxx>
- Date: Sun, 02 Dec 2012 17:42:01 -0800
High ESR capacitors may or may not help depending on what the
interconnect between those capacitors and the capacitance in the package
is. In one strategic mistake, a major chip manufacturer traded Vss
signal returns for Vdd_io pads. They overlooked that this practice made
controlling resonance around the transition from the PCB PDN to the
in-package PDN very difficult.
If you don't know what the package looks like, measure it, or send it
out for measurement to a capable facility such as Tom Dagostino's
Teraspeed Labs.
Steve
On 12/2/2012 5:24 AM, luping liu wrote:
> Hi Steve:
>
> Thanks,I just want to get a clean power, the questions comes from a ASIC
> vendors reference design which suggest us to use high ESR 100nF/0402 decouple
> capacitors,I wonder if this chip has some trouble in control the anti
> resonance between the package and the board,that means taming just the PCB
> may be in trouble.
>
> Regards,
> LIU Luping
>
>> Msg: #3 in digest
>> Date: Thu, 29 Nov 2012 07:33:16 -0800
>> From: steve weir <weirsi@xxxxxxxxxx>
>> Subject: [SI-LIST] Re: How can we get the resonance
>> frequency and Q between
>>
>> Measure S21 from a vantage point at two sides of the chip
>> power
>> connections. Depending on what else is on that rail
>> you may have to
>> perform multiple measurements in multiple locations in order
>> to isolate
>> what is due to that chip. There are various techniques to
>> derive
>> estimates of what is under the chip's hood by making
>> multiple
>> measurements. You may find some of them are on
>> Istvan's site. If you
>> are just trying to deliver clean power to the chip, finding
>> and taming
>> the PCB => package cap / die cap resonance s/b good
>> enough. If you are
>> trying to reverse engineer a chip, then you have more work
>> to do.
>>
>> Steve.
>> On 11/29/2012 6:54 AM, luping liu wrote:
>>> Dear Experts:
>>>
>>> If we have a board with
>> a "blackbox" chip,which means we know nothing about the
>> package and the die details, how can we get the
>> anti-resonance frequency and Q between the package and the
>> board ? The measurement we can do is the Z11 looking from
>> the PCB (with the BGA chip mounted or a bare board with
>> decouple capacitor) with a two port VNA test.Is it possible
>> to get the Cpackage and Cdie?
>>> Thanks and Regards,
>>>
>>> LIU Luping
>>>
>> ------------------------------------------------------------------
>>> 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 forum is accessible at:
>>>
>> http://tech.groups.yahoo.com/group/si-list
>>> 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
>>>
>>>
>>>
>>
>> --
>> Steve Weir
>> IPBLOX, LLC
>> 150 N. Center St. #211
>> Reno, NV 89501
>> www.ipblox.com
>>
>> (775) 299-4236 Business
>> (866) 675-4630 Toll-free
>> (707) 780-1951 Fax
>>
>> All contents Copyright (c)2012 IPBLOX, LLC. All Rights
>> Reserved.
>> This e-mail may contain confidential material.
>> If you are not the intended recipient, please destroy all
>> records
>> and notify the sender.
>>
>>
>> ------------------------------
>>
>
--
Steve Weir
IPBLOX, LLC
150 N. Center St. #211
Reno, NV 89501
www.ipblox.com
(775) 299-4236 Business
(866) 675-4630 Toll-free
(707) 780-1951 Fax
All contents Copyright (c)2012 IPBLOX, LLC. All Rights Reserved.
This e-mail may contain confidential material.
If you are not the intended recipient, please destroy all records
and notify the sender.
------------------------------------------------------------------
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
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:
