Upload
tecnalia-research-innovation
View
1.777
Download
18
Embed Size (px)
Citation preview
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
Filter topologies – LC-Filter
Filter topologies – LC-Filter
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
• Compare simulated vs. measured
• 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
• Compare simulated vs. 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)
PCB mounted EMC ferrites
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
PCB mounted EMC ferrites
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
- Data/Signal line filtering
EMC Phenomena
– Radiated Emission
– Radiated Immunity
– Conducted Emissions
– Conducted Immunity
– 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
Retro fit EMC ferrites
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
Retro fit EMC ferrites
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
- Data/Signal line filtering
EMC Phenomena
– Radiated Emission
– Radiated Immunity
– Conducted Emissions
– Discontinuous Conducted Emissions
– Conducted Immunity
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
What do I need to know to be able to select one?
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
- AC power line (4 to 40Vac rms) protection
- DC power line (5.5 to 56Vdc) protection
WE-VD
Application
- AC power line (14 to 1000Vac rms) protection
- 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
What do I need to know to be able to select one?
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
– Radiated Immunity
Effective frequency range
– 30MHz to 18GHz
EMI Shielding material
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
EMI Shielding material
Earthing cable connectors
Earthing nylon clips
Earthing belts
WE-FAS EMI
WE-FAS RFID
WE-FSFS
WE-SECF
WE-SHC
EMI Shielding material
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)
EMI Shielding material
Surface resistance
EMI Shielding material
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