emc. wurth electronics (uk) ltd

Wurth Electronics (UK) Ltd

1

EMC Seminar 2015

Speaker

Glen Wallis

Senior Field Application Engineer

Agenda

- What is EMC?

- Magnetic and Material Basics

- Transmission Modes & Filter Topologies

- Component Solutions

- Design Guides

2

What is EMC?

EMC Standards and tests are seen by customers as

HUGE PROBLEMS

Economical point of view:

Cost

Pre-design Prototype Production Time

EMC Effect

• dependent on when EMC conformity is considered in a design phase

EMC, what frequency range does it cover?

6

Magnetic and Material Basics

EMC – Electromagnetic Wave

Mai 10 AR 9

Electromagnetic Wave

EMC – Electromagnetic Wave

1 cycle = 0o to 360o

360o

Frequency (F) = 1 / Period

= 1 / 20uS

= 50 kHz

Wavelength (λ) = Speed of Light (m/s) / Frequency

= 3x108 / 50x103

= 6000 metres

20us

0S

Period (S) = 0 seconds to 20uS

0o

Electric field

Magnetic field

The magnetic field

Each electric powered wire generates

an electro magnetic field Field model

current I

Magnetic field H

12

Right Hand Rule

13

The magnetic field - Field model

Magnetic Fields – The magnetic field

NORTH

S OUTH

Magnetic field H

Current I

15

The magnetic field – Field Model

R

ImAH

2)/(

R

INmAH

2)/(

l

INmAH

)/(

Straight wire

Toroidal

l

R

R

solenoid

I = Current

N = Number of turns

R = Radius

L= Length

H (A/m) = Field strength (A/m)

16

The magnetic field

R

ImAH

2)/(

R

INmAH

2)/(

Straight wire

Toroidal R

R

The magnetic field strength is depending from:

• Geometries

• No. of turns

• Current

17

But NOT MATERIAL

e.g I = 5A, R = 0.2, N =10

=5 / 2 x 3.14 x 0.2

=3.978 A/m

=10 x 5 / 2 x 3.14 x 0.2

=39.78 A/m

The magnetic field

averageR

IHHH

221 1B 2B?

Current I

averageR

1H2H

averageR

The magnetic field

What is permeability?

• un ordered (random position)

• soft magnetic

• ordered

• hard magnetic

Ferrite material Permanent magnet

Relative permeability

• describe the capacity of concentration of the magnetic flux in the material.

• it is a energy factor to magnetize the material

Typical permeability µr : • Iron power :

• Nickel Zinc :

• Manganese Zinc :

50 ~ 150

40 ~ 1500

300 ~ 20000

19

-50 50 150 250

1000

T / °C

500 540

670

770 +15 %

-20 %

- The magnetization depends from the temperature

T therm. movement Alignment Alignment of elementary magnets

Ferromagnetic change to Paramagnetic

Point reached at

µr = ? 1

-40°C 23°C 85°C

Curie-temperature

Temperature influnce

µr

Permeability – Core material parameter 20

Permeability – complex permeability

=1 turn

Core material-Parameter

XL(NiZn) R(NiZn)

Z

X L__22

Z RR

X L

Z

Replacement circuit

21

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0,01 0,1 1 10 100 1000

Core material – Inductors (Storage)

f/MHz

XL(NiZn) XL(MnZn) XL(Fe)

Impe

danc

e

22

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0,01 0,1 1 10 100 1000

Core material – Choke (Filter)

f/MHz

R (NiZn) R (MnZn) R (Fe)

Impe

danc

e

23

Core Losses

Electro Magnetic energy cannot disappear, it will be just transformed into

other energy form energy conservation law

e.g. electrical energy transformed into thermal energy

the core losses from ferrite transform the noise energy into heat

Transmission Modes

&

Filter Topologies

Transmission modes

Live (Positive)

Earth (Ground)

Recognize the transmission mode:

Differential Mode

signals on a

line(s) with a return path

Common Mode

noise on all lines

propagating in the

same direction with

respect to earth

Neutral (Return)

Cs

EMC - Coupling

Primary procedure

…to aim at source a low noise

Secondary procedure

… eliminate the noise thru interrupting the coupling way

Tertiary procedure

… increase the noise immunity at load

Noise source Load

Coupling way

Capacitive coupling

• Effects are dominant when the dimensions are 10% below the wave length (l < /10)

-> Why 1/10 ?

-> Reduction ? - Increase the distance

- harmonics

Field model Network model

EMC - Coupling

Inductive coupling

Reduction? - Increase the distance

• Antenna principle –> each piece of wire is a antenna

fc

• Effects are dominant when the PCB traces are ca. 25% from the noise wave length (l < /4)

Field model Network model

EMC - Coupling

Coupling - Wavelengths

Frequency

(MHz)

Wavelength

(m)

H field

1/4 wavelength

(m)

E field

1/10 wavelength

(m)

30 10 2.5 1

100 3 0.75 0.3

500 0.6 0.15 0.06

1000 0.3 0.075 0.03

2500 0.12 0.03 0.012

3000 0.1 0.025 0.01

6000 0.05 0.0125 0.005

Recognizing the coupling mode

common mode noise ?

differential mode noise ?

Common mode or differential mode?

Take a Snap Ferrite and fix it on the cable

(both lines e.g. VCC and GND)

if noise is reduced or

noise immunity increase

you have Common Mode Interference

If not

you have Differential Mode Interference

e.g. Common mode

choke

e.g. chip bead ferrite

• Impedance BA

BFA

ZZ

ZZZA

log20

• System attenuation

BABA

A

FZZZZZ

2010

)(dBin

)(in

Insertion loss – Mathematical Definition

Load Source

ZA ZF

ZB U1 U0 U2

Coupling way

33

Insertion loss – recommended filter topology

Pay attention to:

SRF of used

components

small C = higher SRF

Choose ferrite bead or

inductors L which

= build no resonance with C

= broadband filter

Source Impedance Load Impedance

low

low low

high

high

high

high or

unknow

n

low or

unknow

n

low or

unknow

n

C

L C C

L

L

C

L

high or

unknow

n

Filter design

How to?:

defined filter using 2 components

at least 1 component must be frequency dependant

Matching the working frequency for the signal

Matching the cut of frequency for the noise

Filter input Z 1

Z 2U E U A

Filter output

Conclusion: Filter are frequency dependant voltage divider

35

Low pass filter

…are most popular used filter for EMI

U E U A

L

C

1U E U A

LPF 1. rank

LPF 2. rank

C

1

R

f ZC

f ZL

f ZC

36

-40

-35

-30

-25

-20

-15

-10

-5

0

1 10 100 1000

Frequenz [MHz]

Filter topologies – L-Filter

• L-Filter

Zmax= 3000 Ω @ 80 MHz

• WE-CBF 742 792 093

AF = -29 dB @ 80 MHz

Simulated Measured

• instead of inductor use

SMD-Ferrite

-90

-81

-72

-63

-54

-45

-36

-27

-18

-9

0

1 10 100 1000

Frequenz [MHz]

Filter topologies – Parallel-C-Filter

• Parallel-C-Filter

• Resonant freq.

Filter topologies – LC-Filter

• LC-Filter

WE-CBF 742 792 093

C=100nF

-90

-81

-72

-63

-54

-45

-36

-27

-18

-9

0

1 10 100 1000

Frequenz [MHz]

Simulated Measured

• Compare simulated vs. measured

Design-Tip: avoid over current (load dump)

Uin

e.g. 12V DC

SMD/Ferrite

+

Umax

U(t)

Imax

I(t)

2 3 4 5

2 3 4 5



Uin

e.g. 12V DC

SMD/Ferrite

+

Design-Tip: avoid over load of bead ferrite!

• Safety for SMD-Ferrite against low dump current

• Not an PI-Filter

Capacity C1 is just for stabilizing

Filter topologies – PI-Filter


• π-Filter

WE-CBF 742 792 093

C1=1nF

C2=100nF

-90

-81

-72

-63

-54

-45

-36

-27

-18

-9

0

1 10 100 1000

Frequenz [MHz]

Simulated Measured

Filter topologies – T-Filter

• T-Filter

C=100nF

L1=742 792 040

L2=742 792 093

-90

-81

-72

-63

-54

-45

-36

-27

-18

-9

0

1 10 100 1000

Frequenz [MHz]

Simulated Measured


Common Mode Filter – Signal theories

Transmitter/

Source

Receiver/

Load differential

common

Data lines

Noise mode:

• Common mode noise

• Differential mode noise

D-

D+

e.g.: USB

44

It is a Bi-directional filter

• From device to outside environment

• From outside environment to inside

device

Conclusion:

Common Mode Filter – How it works

Intended Signal - Differential mode

Interference Signal (noise) – Common Mode

• “almost” no affect the signal - Differential mode

• high attenuation to the interference signal (noise) – Common Mode

Source Load Signal path

Common mode

VCC

GND

D-

D+

e.g.: USB Filtering

WE-CNSW Type 0805

Common Mode Filter – Signal theories

Filter with two inductors

Filter input Filter output

Filter with CMC

Filter input Filter output

• Signal not affected

• Noise attenuated even close to the signal frequency

Common mode choke - advantages

USB1.0

IC

USB1.0

IC

Spektrum

-80

-70

-60

-50

-40

-30

-20

-10

0

0 500 1000 1500 2000 2500 3000

Frequenz in MHz

Leis

tun

g in

dB

m

D+

D-

D+

D-

filtered un filtered Tx signal

RF-Generator

Common Mode Choke Common Mode Choke

Data source

Common mode choke – application USB

32 Ohm

0.7 Ohm

Increase Z Fail rate: 3.4% Fail rate: 2.55%

Fail rate: 0% Fail rate: 2.05%

@ 12 MHz CM

DM

41 Ohm

0.7 Ohm @ 12 MHz

CM

DM

363 Ohm

1 Ohm @ 12 MHz

CM

DM

77 Ohm

1 Ohm @ 12 MHz

CM

DM

Common Mode Choke

D+

D-

D+

D-

Increase Z

Common mode choke - construction

SMD-Ferrite – application USB

Fail rate: 0‰

Fail rate: 4.4% Fail rate: 7.5%

35 Ohm @ 12 MHz

DM

110 Ohm @ 12 MHz

DM

Using an WE-CBF instead of CMC

2 x SMD-Ferrit

D+

D-

D+

D-

Increase Z

Component Solutions

How to resolve EMI using EMC counter measures

52

PCB mounted EMC ferrites

Ideal time is to design these series of components in at the product

design stage

Why?

The benefits are as follows:

1. Small package size, thus footprint.

2. Saving valuable PCB space

3. Allows for positioning close to the EMI source or point of filtering

PCB mounted EMC ferrites- Key points

Applications

- DC power line filtering

- Low voltage AC power line filtering

- Data/Signal line filtering

EMC Phenomena

– Radiated Emission

– Radiated Immunity

– Conducted Emissions

– Conducted Immunity

– Electro Static Discharge (ESD)

– Electric Fast Transients (EFT)


Majority are Differential mode filters

– WE-CBF

– WE-CBF HF

– WE-MPSB

– WE-PBF

– WE-PF

– WE-SUKW

– WE-UKW

– WE-WAFB

Maximum operating voltage

- 80Vdc

- 42Vac


WE-CBF (Chip Bead Ferrites)

Three types in the series

High Speed Wide Band High Current

WE-CBF vs WE-CBF HF

Both are 0603 package size, Z = 1k Ω @ 100MHz

WE-CBF WE-CBF HF

WE-CBF HF has greater than 3 times the impedance at 1GHz

CBF DETAILS/READING DATASHEETS

WE-CBF WE-CBF HF

Retro fit EMC ferrites - Key points

Applications

- AC power line filtering

- DC power line filtering


EMC Phenomena





– Electric Fast Transients (EFT)

Retro fit EMC ferrites

These components are design to be fitted to cables or cable harnesses

These are all Split ferrites. Design for quick application to the cable

* Use a unique ‘key’ system that reduced

unauthorised removal of the ferrite

Snap ferrite sleeve

Snap ferrite ring

WE-NCF

Split EMI ferrite ring

Split EMI flat ferrite

STAR-BUENO *

STAR-FIX *

STAR-LFS *

STAR-TEC *

STAR-GAP *

STAR-RING *

STAR-FLAT *

Only manufacturer to offer this key system


Mai 10 AR 61

STAR – xxx series

FIX - LFS TEC / RING /FIX GAP

12 1

10

23 100

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1 10 100 1000

f/MHz

Retro fit EMC ferrites – Number of turns

MnZn NiZn

2 turns


These ferrites are defined as solid core

WE-SFA

WE-FLAT

WE-FAP

WE-FLAT (Flexible PCB)

WE-TOF

WE-AFB

WE-AFB LFS

WE-SAFB

Mutli-Aperture ferrite

Used largely to replace the split ferrites used during

EMC testing

Have to be applied to the cable/cable harness prior to

any connectors are crimped to the ends of the cables

These components are design to be fitted to cables and cable harnesses

Where do we place the ferrite ?

Design:

As close as possible to the

source of the noise

Ideally 20mm to 50mm from the

point of cable connectivity

Recognizing the coupling mode

common mode noise ?

differential mode noise ?

How can we find out what interference we have?

Common mode or differential mode?

Take a Snap Ferrite and fix it on the cable

(both lines e.g. VCC and GND)

if noise is reduced or

noise immunity increase

you have Common Mode Interference

If not

you have Differential Mode Interference

e.g. Common mode

choke

e.g. chip bead ferrite

• Impedance

BA

BFA

ZZ

ZZZA

log20• System attenuation

BABA

A

FZZZZZ

2010

)(dBin

)(in

Insertion loss - Definition

Load Source

ZA ZF

ZB U1 U0 U2

Coupling way

>90

1

10

System Impedances

1

50 - 90

10

System Impedances

The problem

Example, Radiated Emission plot

Mai 10 AR 71

Quick Solution

Impedance of ferrite (Ω)

Att

en

ua

tio

n (

dB

)

1. 1.Require 20dB of

attenuation at 125 MHz

2. Know that it is a power

cable

3. Power port has 10 Ω

impedance

180

• Result is a minimum

impedance of 180Ω

The result

Example with Ferrite fitted Example, Radiated Emission plot

Filter Chokes

WE-CPU Plate

Current compensated common mode chokes -

Key points

Applications – Power line

- AC power line (110 to 250Vac rms) filtering

- DC power (<250V) line filtering

Applications – Signal/Data line

- Low voltage (<42V) AC power line filtering

- DC power (<80V) line filtering


EMC Phenomena




– Discontinuous Conducted Emissions


Common mode choke - construction

bifilar sectional

Data/Signal lines Common mode chokes

Rated at 80Vdc or 42Vac (except WE-CNSW 50Vdc)

WE-CNSW – 0603, 0805 & 1206 sizes. Bifilar wound

WE-SLM - Bifilar wound

WE-SL1 – Sectional wound

WE-SL2 - Bifilar wound & Sectional wound (denoted with a S)

WE-SL3 - Either 2 or 3 wire. Bifilar or Trifilar wound

WE-SL5 - Maximum current 2.5A Bifilar wound & Sectional wound

(denoted with a S)

WE-SL5HC - Maximum current 5A Sectional wound

WE-SL – Either 2 or 4 wire. Bifilar or Quadfilar wound

P/N:

EP-CBF-0805 SMD Ferrite 0805

EP-CBF-1206 SMD Ferrite 1206

EP-STROKO WE-SLxy… Series SMD common mode chokes

VPE 12 pcs. Price £20 inclusive P&P

Application demo boards

Common mode chokes – Power lines

Rated at 250Vac rms @ 50/60Hz, maximum current is 35A

Also possible to pass high current DC through them

WE-CMB

WE-CMB HC

WE-CMB NiZn*

WE-LF

WE-LF SMD

WE-FC Mini

WE-FC

WE-TFC

Used for low frequency suppression in the frequency range of 150KHz to 30MHz.

* 30MHz to 300MHz due to NiZn core

Common mode chokes – line card

Insertion loss (common mode) WE-CMB XS: MnZn <=> NiZn

0

10

20

30

40

50

60

70

0,1 1 10 100 1000

frequency [MHz]

att

en

uati

on

[d

B]

14 µH

30 µH

47 µH

100 µH

1 mH

5 mH

10 mH

20 mH

39 mH

CMB NiZn CMB MnZn

Nano Crystalline – WE-CMBNC

80

Internal structure

81

WE-CMB Impedance vs Temperature

82

1

10

100

1000

10000

100 1000 10000 100000

Imp

ed

an

ce (

Oh

m)

f (kHz)

CMB @ -40

CMB @ 80

CMB @ 120

CMB @ 150

CMB @ 180

2014-02-24 / IMA

WE-CMBNC Impedance vs Temperature

83

1

10

100

1000

10000

100 1000 10000 100000

Imp

ed

an

ce (

Oh

m)

f (kHz)

CMBNC @ -40

CMBNC @ 80

CMBNC @ 120

CMBNC @ 150

CMBNC @ 180

2014-02-24 / IMA

Cost saving?

Insertion loss (common mode) WE-CMB XS: MnZn <=> NiZn

0

10

20

30

40

50

60

70

0,1 1 10 100 1000

frequency [MHz]

att

en

uati

on

[d

B]

14 µH

30 µH

47 µH

100 µH

1 mH

5 mH

10 mH

20 mH

39 mH

CMB NiZn CMB MnZn

CMB NC

Circuit Protection – Key points

Applications

- AC power line (14 to 1000Vac rms) protection

- DC power line (18 to 1465Vdc) protection

- Signal/Data line protection

EMC Phenomena

– Electro Static Discharge (ESD)

– Electrical Fast Transients (EFT)

– High Energy Surges (HES)

The EMC phenomena can be defined as a transient event, a phenomena that's presence is not constant

These products are for protection against over

voltages

Why do we need circuit protection?

Mai 10 AR 86

Circuit Protection

What is an over voltage?

Typically 500V to 15kV

AC voltage 230V ± 10%

Over voltage > 260V

Circuit Protection

The following components are

WE-TVS Standard Series

WE-TVS High Speed Series

WE-TVS Super speed Series

WE-VE

WE-VE ULC

WE-VEA

WE-VEA ULC

WE-VS

WE-VD

Circuit Protection – ESD/EFT

TVS Diodes – Transient Voltage Suppressors

WE-TVS Standard Series

Application = USB 1.1 (12Mbps)

WE-TVS High Speed Series

Application = USB 2.0 (480Mbps)

WE-TVS Super speed Series

Application = USB 3.0 (4.8Gbps)

These devices can be used to protect the DC power and also the signal lines

in one package

Waveshape - ESD

ESD

Maximum rise time = 1ns

Duration = approx 40ns

Maximum pk I (8kV) = 30A

Mai 10 AR 90

Waveshape - EFT

FTB/EFT

Rise time 5nS

Duration 50ns

Mai 10 AR 91

Circuit Protection - TVS

What do I need to know to be able to select one?

USB – 2 Port solution (ESD/EFT solution)

Mai 10 AR 93

USB – 2 Port solution (ESD/EFT-EMI solution)

Mai 10 AR 94

LAN ESD/EFT-solution

Mai 10 AR 95

Circuit Protection - ESD

The WE-VE series of components are suited for the ultra fast voltage pulses

caused by Electro Static Discharge

The following components are

WE-VE

WE-VE ULC (Ultra Low capacitance)

WE-VEA

WE-VEA ULC (Ultra Low capacitance)

These devices are applied to the DC power and also signal/data lines

Circuit Protection - ESD


Layout design

Mai 10 AR 98

Mai 10 AR 99

USB 2.0 filter dongle

P/N 829999 BAG

Mai 10 AR 100

WE-USBH Connector with Integrated EMI & ESD function

Full Speed – 480MHz

P/N 8492121

Mai 10 AR 101

WE-USBH Connector with Integrated EMI & ESD function

Circuit Protection - HES

Surge protection devices

WE-VS

Application


- DC power line (5.5 to 56Vdc) protection

WE-VD

Application


- DC power line (18 to 1465Vdc) protection

What size of varistor to select?

Vrms or Vdc

Peak I (A)

Wmax (J)

Pdiss (W)

It is necessary to calculate (estimate) the maximum

surge current that could flow through the varistor

Parameters to consider:

Operating Voltage

Maximum withstand surge current

Maximum energy absorption

Maximum Power dissipation

Surge Test - Waveforms

Mai 10 AR 104

Test waveforms as specifed by the test method EN 61000-4-5:2006:

Open Circuit

Rise Time : 1.2 µs

Duration : 50 µs

Short Circuit

Rise Time : 8 µs

Duration : 20 µs

Varistor Characteristics – V I Curve

+U

+I

VVar VC VM

IL

IVar

Ic

IMax

Max. Operating Voltage

Clamping Voltage

Leakage Current

0,1mA or 1mA

Current @ Clamping Voltage

U-I Graph for SMD-Varistor 825 42 350

0

1

2

3

4

5

6

7

30 40 50 60 70

Voltage [V]

Cu

rren

t [m

A]

max. Current

Varistor Breakdown Voltage

EUT

Common Mode Z = 12Ω

E

Power lines

L1

L2

L3

Signal lines

Differential Mode Z = 2Ω

Signal lines Z = 42Ω

Surge Test - Application

Calculation of the current: Ic

According to Ohms Law

Surge Voltage (kV)

Z (Ohms)

Supply Voltage (Vpk)

Surge Clamping

Ic

Impedance of the generator according to the type of port (Power or Signal) I load

I load is negligible =>

Method 2

Second Method ( estimation)

Vclamp ~ 2*V breakdown

7mm Disk Varistor VRMS 275 V

V breakdown : 430V

14mm Disk Varistor VRMS 275 V

V breakdown : 430V

Method 2

Calculation of the Energy Absorption

• The energy in Joules (Watt per second) is

given by the following formula:

W (J) = K * V (V) * I (A) * t (s)

Surge Clamping

I Max • It can be difficult to make an exact

calculation of the energy.

• We can make an approximation, in

considering rectangular wave.

• V = Vclamp (just calculated before)

• I = Ic ( just calculated)

• T = 20µS ( time duration of the surge current)

W (J) = Vclamp(V) • Ic (A) • 20µ(s)

50µs

20µs

T(s)

Surge Voltage

Surge Current

Calculation of the Power dissipation

Method 2

FAE Dez. 2011

Circuit Protection - MOV


Derating curve according to the number of applied pulses

Num

ber

of surg

es

Example: Surge spaced 30 seconds.

Time (s)

Tem

pera

ture

(C

)

Layout of varistor for surge protection

Safety standards disapprove for varistors to Earth

Also the product likely to fail the Hi-pot, earth leakage test

If using fuses they must be suitable rated against

surges.

i.e Anti-Surge (T)

FAE Dez. 2011

UL 1449 3rd Edition

The WE-VD are typically designed into a product to protect against an

overvoltage situation that could potential damage the product

It therefore makes the WE-VD are “safety critical component”

Underwriters Laboratory Inc. (UL) is a US based testing and Certification

organisation

UL 1449 3rd Edition is a safety standard for circuit protection devices

Has four classes listed

Type 1 – Protection of the mains distribution network

Type 2 – Protection of permanent connected devices the mains

distribution network

Type 3 - Protection of non permanent connected devices the mains

distribution network

Type 4 – Discrete components

WE-VD are approved for Type 2, 3 & 4

EMI Shielding material

The products can be constructed of two classes of

material when it comes to RF:

1. Metallic – Aluminium, Steel, Brass, Copper

Natural shielding material

2. Non Metallic – Plastic, Nylon, Polystyrene, PVC.

RF transparent materials

EMI Shielding material – Key points

Applications

Shielding of non metallic enclosures

Bonding of metallic enclosures

Absorbing (Attenuating)

EMC Phenomena

– Radiated Emissions


Effective frequency range

– 30MHz to 18GHz


WE-LT- RF gasket

WE-LTS – Stamped gasket

WE-LS – Conductive foam

WE-ST – Conductive weave

WE-CF – Copper tape.

Largest user of copper tape are the

EMC Labs

WE-TS – Textile tape


Earthing cable connectors

Earthing nylon clips

Earthing belts

WE-FAS EMI

WE-FAS RFID

WE-FSFS

WE-SECF

WE-SHC


RF Gasket, WE-LT and WE-GS can

be used in the following

configurations to establish a good

bond

To enable good electrical

conductivity, gasket must make

direct metal work to metal work

contact

Any painted surface will act as an

insulator (high resistance to RF)


Surface resistance


WE-FAS EMI

WE-LS

Ethernet EMI solution

Ethernet EMI solution: WE-RJ45 HPLE

Leakage inductance shielded vs. unshielded

Radiation by inductor

WE - PD2 unshielded

10µH, 2MHz clock, 1A

Radiation by inductor

WE – PD shielded

10µH, 2MHz clock, 1A

19dBm

improvement

• consider start of winding

Inductors are two poles only

but start of winding is important

use effect of self shielding of the winding

connection switch node

“EMI hot side”

Self sheilding

Design Guides

Catalogue

EMC Components

Power Magnetics

Signal & Communications

Additional technical drawing data supplied (inc. tolerances)

Also addition of QR codes

Trilogy of Magnetics

Now published as 4th edition

Three sections:-

Magnetic basics

Components

Application notes

Filtering

DC/DC PSU design

Design Tools

LT Spice Simulator

WE Component Selector

Inductor Selector

WE-Flex transformer designer

RF inductor Selector

Chip Bead Ferrite Selector

Lab rack/design kits

THANK YOU

&

Any Questions

emc. wurth electronics (uk) ltd

Services