[SI-LIST] Re: Mixed digital/RF board with switching power supplies
- From: Boris Traa <boris.traa@xxxxxxxxxxx>
- To: matusov@xxxxxxxxxxxx
- Date: Fri, 6 Jul 2007 17:59:07 +0200
Dear Mikhail
Are the circuits that are interfered implemented as differential
circuits?
Kind regards
Boris Traa
System design engineer EMC
It's the currents that make circuits work or fail.
Philips Applied Technologies/EM&C Competence Center
Room 1.024
High Tech Campus 26
5656AE Eindhoven, The Netherlands
Tel: ++ 31 40 27 43766
Fax: ++ 31 40 27 42224
E-mail: boris.traa@xxxxxxxxxxxx Seri: nlv09273@nlwayhp
"Mikhail Matusov" <matusov@xxxxxxxxxxxx>
Sent by:
si-list-bounce@xxxxxxxxxxxxx
06-07-2007 16:27
Please respond to
matusov@xxxxxxxxxxxx
To
<si-list@xxxxxxxxxxxxx>
cc
Subject
[SI-LIST] Mixed digital/RF board with switching power supplies
Classification
Dear experts,
I have designed a mixed digital/RF board, which performs rather well, but
we
want it to perform even better in the next revision. The problem we are
having is spurious components in the RF chain caused by the high harmonics
of the DC/DC switching regulators. The regulators run at about 1.2 MHz and
the band of our interest is roughly 50 to 90 MHz, although obviously,
since
it is a sampling system, much higher harmonics can be aliased into the
band
of interest... The absolute level of the offending components is -94 dBm
and
below, so it is in microvolts, which probably makes it more of an EMI sort
of problem than a SI one. I believe, based on some experiments we did,
that
the problem is caused by the switching currents travelling in the ground
planes. The board is quite dense and there is no easy way to divide it
into
an analog and digital sections... I was wondering if someone here has any
experience in resolving this sort of problems? Also, what would be the
best
book to pick up on the subject? I looked at a few EMI/PCB design books on
Amazon, but couldn't make my choice as their "look inside" feature is very
limiting and wouldn't let me see the chapters I wanted... The books I am
considering are Introduction to Electromagnetic Compatibility by Paul
Clayton, Noise Reduction Techniques in Electronic Systems by Henry Ott,
EMC
& and the Printed Circuit Board by Mark Montrose...
Thanks,
=======================
Mikhail Matusov
Senior Hardware Design Engineer
Square Peg Communications
Tel.: +1 (613) 271-0044 ext.231
Fax: +1 (613) 271-3007
http://www.squarepeg.ca
------------------------------------------------------------------
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
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
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
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
