Transcript ESD Generator Modelling

CST STUDIO SUITE™ 2006
EMC - Application and Feature Tutorial
Immunity to ESD on ITE /
Lightning and NEMP
E. Leroux
Cable to the
Oscilloscope
Internal
loop
ESD
simulator
Point
A
Strap
1
Point
B
Slot
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Simulator Body
Immunity to ESD on ITE
equipments.
Metal Wall
Strap
ESD generators, immunity test, ITE
equipments definitions
Induced voltage in a square loop
located inside an enclosure-ESD to VCP
Discharge Coupling
Cable to the
Oscilloscope
Internal
loop
ESD
simulator
Point
A
Strap
Point
B
Slot
Application to another type of
equipment: Discharge on an
Cellular Phone
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Definitions
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ESD Background
Electrostatic Discharge (ESD) is the abrupt release of charge from one object
(often a person) to another. Such a discharge can permanently damage or
otherwise upset the function of sensitive electronic circuits.
Electronic products are tested for ESD immunity to insure their continued
reliable operation if subjected to realistic levels of ESD after being placed in
service. The European Union’s EMC Directive mandates ESD immunity
testing for virtually all electrical and/or electronic products as a condition for
obtaining the CE Mark before shipping to a member state of the European
Union.
Applicable Standards
Generic Immunity Standards, Product Standards and Product Family
Standards require that ESD tests be performed in accordance with specific
Basic EMC Standards: IEC 801-2, IEC 61000-4-2, or EN 61000-4-2.
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ESD measurement setups
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Conception of a ESD generator model
With courtesy of S. Caniggia: ITALTEL,
D. Pommerenke, W. Kai: University of Missouri-Rolla
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ESD generators are widely used for testing the robustness of electronic equipment against human-metal
ESD. ESD can disturb systems by its current and the associated fields.
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To predict the susceptibility of a system, a sufficiently accurate model of the ESD generator (gun) is
needed.
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In this first part a simplified ESD generator model is presented using MWS.
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The current distribution on the generator is not predicted as long as the geometry of the generator and
the ground strap are not part of the model.
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Therefore the problem of simultaneously calculating an ESD generator and a susceptible structure
becomes feasible
In the next slide, ESD generator discharged into a large ground plane In order to
verify the ESD generator model, the discharge into a large ground plane was
simulated. The current injected from the ESD generator into a large metal wall was
measured, and the generator was numerically modeled as in this figure. The
geometry of the ESD generator was optimized for obtaining a good match to the
measurement, while keeping it as simple as possible.
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ESD Generator Modelling
Simulator Body
10 pF
150 pF


Metal Wall
Excitation
Port 25 
Strap
2 pF 
1 
Simulation
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5
4
4
Current [A]
Measurement
3
2
3
1
0
2
0
5
10
15
1KV Discharge current in the standard tip
1
0
6
0
100
Time [ns]
200
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Induced voltage in a square loop located
inside an enclosure
The electromagnetic field due to the ESD
current between the points A and B excites
the enclosure. The square loop placed into
the cavity senses the internal electromagnetic
field and is then used to compare numerical
and experimental values. Same enclosure and
measurements set up as in Graziano Cerri,
Roberto De Leo, Roberto De Rentiis, Valter
Mariani Primiani. “ESD Field Penetration
Through Slots into Shielded Enclosures: A
time Domain Approach”. IEEE Trans. on EMC,
Vol. 39, NO. 4, November 1997.
Cable to the
Oscilloscope
Internal
loop
ESD
simulator
Point A
Slot
Point B
Strap
Voltage [V]
2
Simulation
Measurement
1
0
-1
-2
7
0
5
10
Induced
voltage in the square loop for the first
10 ns
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Time
[ns]
Typical test setup for discharges to the VCP
The proposed model of the ESD generator was tested on the
horizontal coupling plane (HCP) and the vertical coupling plane
(VCP). We study the coupling with a mouse cable, which was added
parallel to the VCP as a susceptible circuit.
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ESD to VCP Discharge Coupling
Using the simplified model of the ESD generator,
the voltage induced on the cable is simulated,
and the results are compared with the results
obtained in David J. Pommerenke, Thomas P.
Van Doren, Wang Kai, ‘ESD Currents and Fields
on the VCP and the HCP Modeled Using Quasistatic Approximations’, IEEE Int. Sym. EMC,
Minneapolis, Minnesota, 2002.
Voltage [V]
2
Measurement
1
0
-1
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Simulation
0
20
40
Time [ns]
60
80
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Conclusions
• Using a UDF as an excitation function and a simplified ESD generator
model, the induced currents and fields, as seen during susceptibility test, can
be modeled using MWS. Within the accuracy bandwidth of the model, the
results agree well with the measurements.
• A higher accuracy is achieved in the model presented relative to enforcing a
current in disregard to the ESD generator geometry and internal components.
Relative to the fully detailed model of the charging and rapid discharging
process, the ability to design ESD generators via numerical techniques is lost.
However, sufficient accuracy to predict susceptibility is maintained creating
much shorter calculation times.
•The same ESD “gun” model idea can be used to test other devices and not
only ITE equipments….other UDF can be used to deal with other EMC tests…
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Discharge on an Cellular Phone
Similar Device
Measurement
Simulation
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3
Current [A]
2
1
2
0
0
2
6
10
14
1
0
0
10
20
30
40
Time [ns]
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Another example of EMC
simulation with MWS
INDUCED CURRENT ON A
RADAR DUE TO
A DIRECT LIGHTNING
STRIKE
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Another example of EMC
simulation with MWS:
Nuclear EM Pulse – NEMP coupling with an antenna
array
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Array of patch antenna above a finite
ground plane exited by the NEMP
(plane wave)
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Input Plane wave signal
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Position of the port located between
one port and the finite ground
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Current at the port, leads to an energy
of 2.8 E-11 Joules
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