Re: [PSES] SV: Ferrite bead vs. resistor

[alfred1520list]

I don't know your circumstances but I can understand why in some situations 
adding a resistor help. In many circuits a driver side series termination is 
part of the circuit design to match the driver impedance to the trace impedance 
for source termination. The effect of this is that any reflections are absorbed 
by the driver when it is reflected back and therefore preserve the signal 
integrity at the receiving end. A side effect could be that there is less 
ringing which results in less EMI. You need to look closely at your design to 
under the mechanics of your problem and device a solution.

Alfred

On February 5, 2016 1:00:25 AM PST, Amund Westin  
wrote:
>A resistor will cause a voltage drop, and that could make problems for
>the functionality. Ferrite bead will not make a DC voltage drop.
>
>For higher frequencies (above 100MHz) the bead is more precise
>described (Z, X and R), while the impedance of a resistor is maybe not
>defined.
>
> 
>
>#Amund 
>
> 
>
> 
>
>Fra: Amund Westin [mailto:am...@westin-emission.no] 
>Sendt: 5. februar 2016 09:38
>Til: 'EMC-PSTC@LISTSERV.IEEE.ORG' 
>Emne: Ferrite bead vs. resistor
>
> 
>
>Had some EMI issues, caused by a LVDS line.
>
>By inserting CM chokes, the radiation seemed to lower significant.
>
>Inserting resistors as well (aprox 22 ohm) made it even better. I can’t
>check the eye curve, but 22ohm makes no problem with the EUT operation.
>
> 
>
> 
>
>But, should the series resistor be replaced by ferrite beads instead?
>Will it make any really differences?
>
>The LVDS clock is approx 40MHz and data rate 160Mbps.
>
> 
>
>#Amund
>
> 
>
> 
>
>
>-
>
>This message is from the IEEE Product Safety Engineering Society
>emc-pstc discussion list. To post a message to the list, send your
>e-mail to 
>
>All emc-pstc postings are archived and searchable on the web at:
>http://www.ieee-pses.org/emc-pstc.html
>
>Attachments are not permitted but the IEEE PSES Online Communities site
>at http://product-compliance.oc.ieee.org/ can be used for graphics (in
>well-used formats), large files, etc.
>
>Website:  http://www.ieee-pses.org/
>Instructions:  http://www.ieee-pses.org/list.html (including how to
>unsubscribe)
>List rules: http://www.ieee-pses.org/listrules.html
>
>For help, send mail to the list administrators:
>Scott Douglas 
>Mike Cantwell 
>
>For policy questions, send mail to:
>Jim Bacher:  
>David Heald: 

-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] AU CISPR 22 Class B Interpretation

[Grasso, Charles]

Hello Carl - What does the purchase agreement call for? 

In other words - what are you testing to CISPR22 in the first place?

I suggest you research the medical EMC requirements for devices involved
in ambulances, police cars and so on that will guide you. 


Best Regards
Charles Grasso
Compliance Engineer
Echostar Communications
(w) 303-706-5467
(c) 303-204-2974
(t) 3032042...@vtext.com
(e) charles.gra...@echostar.com
(e2) chasgra...@gmail.com


-Original Message-
From: Carl Newton [mailto:emcl...@gmail.com] 
Sent: Friday, January 29, 2016 10:10 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] AU CISPR 22 Class B Interpretation

Group,

My customer builds vehicular laptop and tablet docking stations intended for 
hard mounted use within emergency vehicles such as police and ambulance, as 
well as work trucks and forklifts.  The vehicular power supply narrowly missed 
CISPR 22 radiated Class B limits.  Then their AU Responsible Party told us they 
called the ACMA and they "insisted" this is a Class B device.  I then sent my 
own request to ACMA and received the reply below.

In my opinion the ACMA individual is clearly biased toward the Class B rating, 
but the fact that he leaves the door open to the Class A rating is enough proof 
for me that he agrees that it is a Class A device.  However, my customer is 
looking for safety in numbers.  The author raises a valid note of caution 
concerning receivers within vehicles, but these systems are already compliant 
with CISPR 25 and are widely used within North America and Europe with no 
interference problems so we're not concerned with that warning.

I would appreciate it if some of you would review this information and provide 
your professional opinion as to whether vehicle mounted ITE qualifies as Class 
A or Class B:

+++

Dear Mr Newton

Clause 4.1 of AS/NZS CISPR 22 (which is identical to CISPR 22, Ed. 6.0
(2008)) includes the following;

Class B ITE is intended primarily for use in the domestic environment and may 
include:

-  Personal computers and auxiliary equipment.

Note: The domestic environment is an environment where the use of broadcast and 
television receivers may be expected within distances of 10 m of the apparatus 
concerned.

Given that the class B limits apply to “personal computers” (which would also 
include “tablets”) it would seem logical that your mounting stations “for 
computers and tablets” (which I would think fall within the definition of 
“auxiliary equipment”) should comply with the same limits as the devices they 
are intended to hold.

I would also think that, because police and ambulance vehicles will probably 
have a broadcast (AM/FM) receiver installed in them this would probably 
constitute a “domestic environment”.  I would also question whether it would be 
prudent to have a device meeting the class A limits installed in a vehicle that 
relies heavily on two-way radiocommunications equipment where said device may 
interfere with the operation of this on-board radiocommunications equipment.

Having said that, clause 4.2 of AS/NZS CISPR 22  includes the following;

Class A ITE is a category of all other ITE which satisfies the class A ITE 
limits but not the class B ITE limits.  Such equipment should not be restricted 
in its sale but the following warning shall be included in the instructions for 
use:

Warning

This is a class A product.  In a domestic environment this product may cause 
radio interference in which case the user may be required to take adequate 
measures.

It is up to you whether you wish to comply with the class A or the class B 
limits however, I would personally err on the side of caution – if an ambulance 
or a police car were unable use its radiocommunications equipment and it turned 
out it was due to interference from your device the legal ramifications could 
be costly.

Regards

XX X
Technical Regulation Development Section
Australian  Communications & Media Authority

++

Thanks group,

Carl



-- 
Using Opera's mail client: http://www.opera.com/mail/

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

-

This m

Re: [PSES] Updated ECHA REACH guidance

[Grasso, Charles]

Hello Lauren,
You asked : A key question --> If an item manufacturer makes a bunch of parts 
to go into an item they sell, but none of the parts are sold as products in 
their own right, are each of the parts a separate simple article?  The current 
state of play on interpreting the ruling is unclear on the answer

My understanding is that Yes each of the parts do constitute a simple article.

My understanding is based on the direction (if you will) that the legislators 
are headed.


Best Regards
Charles Grasso
Compliance Engineer
Echostar Communications
(w) 303-706-5467
(c) 303-204-2974
(t) 3032042...@vtext.com
(e) charles.gra...@echostar.com
(e2) chasgra...@gmail.com

From: Crane, Lauren [mailto:lauren.cr...@kla-tencor.com]
Sent: Thursday, February 04, 2016 11:27 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Updated ECHA REACH guidance

Scott,

This ‘change’ is not an amendment. It is a ruling made by the European Court of 
Justice on a regulation already in force, so technically, but perhaps not 
practically (depending on how enforcement authorities decide to react), it 
applies now, (and *retroactively*, I’ve heard from some commenters) to the day 
the REACH regulation was released.

ECHA guidance nicely claims it is guidance and not legally binding … but the 
practical reality is it is *likely* that authorities won’t begin behaving 
differently until ECHA puts out their big next revision of their “Guidance on 
Substances in Articles” document - which I hope addresses many of the practical 
fine point details.

I completely agree that “it should have a transition period” but I have no idea 
yet whether, in effect, it will get one.


Lauren Crane
KLA-Tencor

From: Scott Xe [mailto:scott...@gmail.com]
Sent: Thursday, February 04, 2016 11:16 AM
To: Crane, Lauren
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Updated ECHA REACH guidance

Hi Lauren,

Does the amendment become effective immediately?  ECHA just amended the 
guidance document after a couple of months.  Does EU need to amend the 
regulation later?

Would it be a big impact on the existing compliance per product.  Probably a 
lot of products become non-conformity due to the change.  It should have a 
transition period for the changes.

Regards,

Scott

On 19 Dec, 2015, at 12:52 am, Crane, Lauren 
mailto:lauren.cr...@kla-tencor.com>> wrote:

I’ve been tracking this for a year or so now and working with a SEMI industry 
working group to follow it. The European Court of Justice did issue their final 
opinion and it does introduce a disruptive understanding of ‘article’. The 
evolving vocab. Is now ‘simple’ articles vs. ‘complex’ articles. The latter 
being assembled from the former. So analysis of computer, when imported, must 
be against each of its constituent simple articles with regard to both REACH 
Article 33 notification criteria and REACH Annex XVII restrictions which set 
limits of concentration per total weight of the simple article.

The devil is now pushed further into the details. What is not clear is what 
constitutes a simple article. Before one had to consider the total item as 
imported. Now one must understand how many ‘parts’ an item has. It is clear 
that the granularity is *not* limited to a products bill of materials (unless 
they nicely interpret into that space, which I wish they would). A simple 
relay, for example, can be argued as being a complex article made up of a case, 
a coil bobbin, a coil, leaf springs, contact buttons etc…..

A key question --> If an item manufacturer makes a bunch of parts to go into an 
item they sell, but none of the parts are sold as products in their own right, 
are each of the parts a separate simple article?  The current state of play on 
interpreting the ruling is unclear on the answer.

ECHA has done a quick revision of their guide on substances in articles to 
remove any overt contradictions with the court ruling, and they have a longer 
term plan to revise the guide to be useful to the new questions raised by it.

The 
ruling

Lauren Crane
KLA-Tencor

From: Dan Roman, N.C.E. [mailto:danp...@verizon.net]
Sent: Friday, December 18, 2015 6:32 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Updated ECHA REACH guidance

I will answer my own question in case anyone else is looking for the same 
thing.  ECHA published version 3 of the guidance document yesterday.  It can be 
found at .  I 
skimmed through it quickly and it was not immediately obvious to me as to 
whether common electronic products like a computer are still treated the s

Re: [PSES] Ferrite bead vs. resistor

[Grasso, Charles]

Hello Amund – If adding a CMC only “seems” to make a difference
then  I suggest you look harder for the cause.

Adding the resistors will lower the signal levels which can reduce
the emissions. So I suggest you measure the eye ASAP.

In general, resistors in signals are better than ferrite beads
for signal quality.

Best Regards
Charles Grasso
Compliance Engineer
Echostar Communications
(w) 303-706-5467
(c) 303-204-2974
(t) 3032042...@vtext.com
(e) charles.gra...@echostar.com
(e2) chasgra...@gmail.com

From: Amund Westin [mailto:am...@westin-emission.no]
Sent: Friday, February 05, 2016 1:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Ferrite bead vs. resistor

Had some EMI issues, caused by a LVDS line.
By inserting CM chokes, the radiation seemed to lower significant.
Inserting resistors as well (aprox 22 ohm) made it even better. I can’t check 
the eye curve, but 22ohm makes no problem with the EUT operation.


But, should the series resistor be replaced by ferrite beads instead? Will it 
make any really differences?
The LVDS clock is approx 40MHz and data rate 160Mbps.

#Amund


-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
mailto:emc-p...@ieee.org>>

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to 
unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas mailto:sdoug...@ieee.org>>
Mike Cantwell mailto:mcantw...@ieee.org>>

For policy questions, send mail to:
Jim Bacher mailto:j.bac...@ieee.org>>
David Heald mailto:dhe...@gmail.com>>

-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] SV: Ferrite bead vs. resistor

[ce-test, qualified testing bv - Gert Gremmen]

In general, if the application can support serial resistance,

a resistor will give you better –reproducible- results.  The inductive part

of a ferrite bead may give resonances, and resistors  are available in much 
wider

ranges. Resistors especially SMD, have good RF properties if used on the proper 
PCB footprint.

Values in general between 22 and 100 ohm.

 

This is my experience with fast Ethernet and TTL level serial connections.

 

I can imagine that laser trimmed resistors have worse characteristics, but

as far as I understand the trimming process that is just in terms of increased 
inductivity

a property that creates less of a problem for this application.

 

The bead’s properties are not always specified completely, most are limited

to a graph of (real and/or imaginary) impedance versus frequency.

 

 

In some cases the inductive impedance is simply to high ( >500) to reduce 
emissions.

 

The source impedance of CM currents is not that of a simple voltage or current 
source,

but a unknown mixture of the 2, and blocking one CM current on one cable will 
increase others.

 

The interference current are principally caused by charging and discharging 
(clock) of semiconductor

internal and external capacitances (0-3 or 0-5V), and each charge discharge 
cycle releases

an amount of energy (0.5 CV2 ) that HAS to be dissipated locally in real 
impedances. Too inductive

beads will not dissipate , and simply reflect the energy. Blocking the currents 
(beads) will rise the

voltage opening other ways out, shorting the voltage (caps) will rise the 
current flowing,

both creating more emissions.

Regards,

Ing. Gert Gremmen



 

From: Amund Westin [mailto:am...@westin-emission.no] 
Sent: Friday 5 February 2016 10:00
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] SV: Ferrite bead vs. resistor

 

A resistor will cause a voltage drop, and that could make problems for the 
functionality. Ferrite bead will not make a DC voltage drop.

For higher frequencies (above 100MHz) the bead is more precise described (Z, X 
and R), while the impedance of a resistor is maybe not defined.

 

#Amund 

 

 

Fra: Amund Westin [mailto:am...@westin-emission.no] 
Sendt: 5. februar 2016 09:38
Til: 'EMC-PSTC@LISTSERV.IEEE.ORG' 
Emne: Ferrite bead vs. resistor

 

Had some EMI issues, caused by a LVDS line.

By inserting CM chokes, the radiation seemed to lower significant.

Inserting resistors as well (aprox 22 ohm) made it even better. I can’t check 
the eye curve, but 22ohm makes no problem with the EUT operation.

 

 

But, should the series resistor be replaced by ferrite beads instead? Will it 
make any really differences?

The LVDS clock is approx 40MHz and data rate 160Mbps.

 

#Amund

 

 

-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 
 
List rules: http://www.ieee-pses.org/listrules.html 

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell  

For policy questions, send mail to:
Jim Bacher 
David Heald  


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

[PSES] SV: Ferrite bead vs. resistor

[Amund Westin]

A resistor will cause a voltage drop, and that could make problems for the 
functionality. Ferrite bead will not make a DC voltage drop.

For higher frequencies (above 100MHz) the bead is more precise described (Z, X 
and R), while the impedance of a resistor is maybe not defined.

 

#Amund 

 

 

Fra: Amund Westin [mailto:am...@westin-emission.no] 
Sendt: 5. februar 2016 09:38
Til: 'EMC-PSTC@LISTSERV.IEEE.ORG' 
Emne: Ferrite bead vs. resistor

 

Had some EMI issues, caused by a LVDS line.

By inserting CM chokes, the radiation seemed to lower significant.

Inserting resistors as well (aprox 22 ohm) made it even better. I can’t check 
the eye curve, but 22ohm makes no problem with the EUT operation.

 

 

But, should the series resistor be replaced by ferrite beads instead? Will it 
make any really differences?

The LVDS clock is approx 40MHz and data rate 160Mbps.

 

#Amund

 

 


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

[PSES] Ferrite bead vs. resistor

[Amund Westin]

Had some EMI issues, caused by a LVDS line.

By inserting CM chokes, the radiation seemed to lower significant.

Inserting resistors as well (aprox 22 ohm) made it even better. I can’t check 
the eye curve, but 22ohm makes no problem with the EUT operation.

 

 

But, should the series resistor be replaced by ferrite beads instead? Will it 
make any really differences?

The LVDS clock is approx 40MHz and data rate 160Mbps.

 

#Amund

 

 


-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: