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EMIStream 12 check items

By Travis Peters,2014-05-27 15:08
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EMIStream 12 check items

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     EMI Rule Check

     1.1 Check the issues caused by return path 1. Traces crossing over power and ground planes 2. Discontinuity of return current path 1.2 Check the issues caused by signal 3. Trace length 4. Number of via 5. Traces near plane edge 6. Estimation of radiated electric field 7. SG traces 8. Filters on a trace connected to a connector 9. Differential Pair 1.3 Check the issues caused by Power 10. Distance between grounding vias of SG traces 11. Grounding vias along to ground-plane edge 12. Decoupling capacitor placement

     2

     EMI 12

     1.

     RETURN PATH) 1.1. vcc planes) 1.2. GND

     EMI

     (CHECK THE ISSUES CAUSED BY (Trace crossing over power and ground

     (discontinuity of return current path)

     2.

     2.1. 2.2. 2.3. 2.4. 2.5. 2.6. 2.7.

     EMI

     (CHECK THE ISSUES CAUSED BY SIGNAL)

     (Trace lenth) (Number of via) (Trace near plane edge) (Estimation of radiated electric field) (SG Trace) (Filters on a trace connected to a connector) (Differential Pair)

     3.

     3.1. 3.2. 3.3.

     EMI

     (CHECK THE ISSUES CAUSED BY POWER)

     (Distance between grounding vias of SG traces) (Grounding vias along to ground-plane edge) (Decoupling capacitor placement)

     3

     PCB Design Flow Up To Now

     Problem causes at Evaluation Stage

     No care No care about Art about Art Work Work PCB Pattern Design A handful of A handful of technical people technical people work for EMC work for EMC Prototype Evaluation

     Limited countermeasures after completion of Design/prototype

     Design

     Schematic Design

     Layout Design

     Manufacture Of PCB

     Packaging

     Estimation

     System Verification

     Mass Production

     Problem causes

     Reiteration Turn back as Problem causes Long TAT

     4

     Improvement of PCB Design Flow

     Execute fundamental counter measures and Solve all problems at

    schematic/layout stage

     Design PCB Pattern Design Prototype Evaluation

     Schematic Design

     Layout Design

     Manufacture Of PCB

     Packaging

     Estimation

     System Verification

     Mass Production

     Floor Planning

     Solve the problem at design step

     All steps can be proceed smoothly

     Complete Design without any reiteration

     5

     (1) Trace length Long wires -> increases current Loop area

     Excess total Length of wires per net

     6

     (2) Numbers of Via-holes Vias cause excitation point of resonance,

    disorder of signal wave

     Exceed number of Via per net

     7

     (3)Traces near plane edges Wires at the edge of Board -> disorder

    range of the Discontinuities of return current path GND Plane

     Wires exists at the edge of plane

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     (4) Traces crossing over GV planes Trace crossing over power and

    ground plane -> discontinuity of return path

     Trace cross over GV planes

     Signal layer Ground plane Power plane Signal layer

     Via

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     (5)Discontinuities of return current path

     Discontinuities of return current path -> Increase current loop area

     SG Trace

     SG pattern leads to Discontinuities

     Slit

     of return current path Discontinuities return current path occurs by across the slit SG Trace Via

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     (6) SG trace check No SG Pattern -> unable to reinforce return current path SG trace

     No SG trace

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     (7)Estimation of radiated electric field

     Differential-mode radiation is calculated using simple equivalent circuit.

     Rout

     Rdump Z0, length I(f)

     Rpkg

     V(f)

     Z(f)

     Rterm

     Cin

     12

     Estimate volume of radiation electric field of common mode based on differential mode

     Large radiation (DM: Large CM: Large)

     Medium radiation (DM: Large CM: Medium) Small radiation (DM: Small CM:Medium) Total radiation =Differential mode radiation + Common mode radiation

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     (8)Distance between grounding vias of SG traces

     Inadequate grounding via interval -> No fulfill SG Pattern function.

     SG Pattern

     Interval of grounding vias is too long.

     There is no via at the end

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     (9) Grounding vias along ground plane edge

     No Via on circumference of the plane -> Decrease Performance of return current path No Via at the corner of the plane

     Exceed distance between Vias Signal GND Plane

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     (10) Filters on a trace connected to a connector Incomplete filters -> noise occur at connectors Connector

     Over distance to the filter Filter

     No filters

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     (11) Differential pair check Differential pair suppose to be low EMI, causes many occasion of EMI

     Check for differential length, parallel, altered Impedance of wires

    -> Available for verification of critical pair wire design

     NetA+ NetA-

     GND

     (b1)Exceed Max (b2)Between Min/Max

     17

     (c)

     (12) Decoupling Capacitor Incomplete Decoupling Capacitor ->

    Excitation Point on Plane

     Decoupling Capacitor

     Over distance to Capacitor

     Too short distance to plane No Decoupling Capacitor

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     Power plane resonance analysis Power plane

     4 10

     Ground plane

     104

     Parasitic resistance/Inductance of Capacitor + Parasitic

    resistance/Inductance of traces/vias

     19

     Interface to Layout CAD systems

     Zuken Cadence Mentor Graphics Visula Allegro

     CR5000/BD

     CR5000/PWS CR3000/PWS

     BoardStation

     PADS Layout

     Protel Orcad

     ASCII OUT

     ExpeditionPCB

     ASCII IN

     Flex I/F

     Backannotation

     BD ASCII

     Design File

     PADS Layout ASCII

     EMIStream BD Interface

     EMIStream PADS Layout Interface

     20

     Solution of EMIStream

     Easy to use.

     Don??t need parameter (Including NEC know how)

     High Speed checking.

     Checking time is 60 seconds average. You can check anytime and no

    stress builds up!!

     Decrease Turn around time.

     Must take measures EMI at design process.

     Decrease EMI engineer??s job

     Many EMI problems are able to be solved at design stage.

     Best match.

     Mentor? HyperLynx(SI) and EMIStream (EMI). provide true solution of measures for noise.

     21

     Thanks

     We hope it will be your best partner and tool.

     http://www.emistream.com

     2004.9.6

     2004 NEC Informatec Systems, Ltd. All rights reserved. EMIStream is trademark of PADS Japan, Ltd. All others are properties of their holders.

     PADS Japan Co., Ltd 3-1-2 Yoyogi Shibuya Tokyo Japan 151-0053 Tel:+81 3 5304 5751 FAX:+81 3 5304 5752 mailto emistream@padsjapan.co.jp

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