WhereEMIfilteringin ESDsensitive equipment is required :
Computers and printers
Communication systems
Mobile phones
MCU Boards
DESCRIPTION
The EMIF02-600FU7 isa highlyintegrated array designed
to suppress EMI / RFI noise in all systems subjected to
electromagnetic interferences.
Additionally, this filter includes an ESD protectioncircuitry
whichprevents theprotected devicefrom destructionwhen
subjected to ESD surges up to 15 kV. The
EMIF02-600FU7 provides best efficiency when using
separated inputs and outputs, in the so-called 4-points
structure.
Breakdownvoltage
Leakagecurrent @ V
Stand-offvoltage
Clampingvoltage
RM
RdDynamicimpedance
I
PP
Peak pulsecurrent
kV
R
I/O
Serialresistancebetween Input
and Output
SymbolTestconditionsMin.Typ.Max.Unit
V
BR
I
RM
R
I/O
R
d
Note 1 : to calculatethe ESDresidual voltage, please refer to the paragraph ”ESDPROTECTION” on pages4 & 5
IR=1mA678V
VRM=3V1µA
Serialresistancebetween Inputand Output480600720Ω
Ipp=10A,tp=2.5µs (see note1)0.55Ω
Fig.1: Relativevariationof leakagecurrentversus
reversevoltage(Typicalvalues)
IR[VR] / IR[VR=3V]
20.0
10.0
5.0
2.0
1.0
0.5
2.53.03.54.04.55.05.5
2/9
VR (V)
Page 3
EMIF02-600FU7
TECHNICAL INFORMATION
FREQUENCY BEHAVIOR
The EMIF02-600FU7 is firstly designed as an EMI/RFI filter. This low-pass filter is characterized by the following
parameters:
- Cut-off frequency
- Insertionloss
- High frequency rejection
FigA1: EMIF02- 600F U 7frequencyresponsecurve.
Figure A1gives these parameters, in particularthe signal rejection at theGSM frequency is about -20dBm at 900MHz,
while theattenuation for FM broadcast range(around 100MHz) is better than -32dBm
FigA2 : Measurementconditions
SPECTRUM
VoutVin
ANALYSER
50
Ω
TG OUTPUT
TEST BOARD
EMIF02
RF INPUT
Vg
50
Ω
EMIF02
3/9
Page 4
EMIF02-600FU7
ESDPROTECTION
In additionto its filtering function, the EMIF02-600FU7 is particularly optimized to perform ESD protection.
ESD protection is based onvoltage clampingwhich can be calculated by :
VCL=VBR+Rd.I
PP
This protection function is splittedin 2stages. Asshown infigure A3,the ESDstrikes areclamped by the first stageS1 and
then its remainingovervoltage is applied to the secondstage through the resistorR. Sucha configurationmakes the output
voltage V
very low.
out
FigA3 : ESDclamping behavior
Rg
ESD
Surge
Vg
Vin
Rd
Vbr
S1
To have a good approximation of the remaining voltages at both Vin and Vout stages, we provide the typical dynamical
resistance value Rd. By takinginto accountthese following hypothesis : R>>Rd, R
formulas:
Vin
=
Vout
R
EMIF02-600FU7
Rg.Vbr+Rd.Vg
Rg
R.Vbr+Rd.Vin
=
R
S2
Rd
Vbr
Vout
Device to be protected
>>Rd and Rload>>Rd, it gives these
G
Rload
The results of the calculation done forVG=8kV, RG=330Ω(IEC1000-4-2 standard) and VBR=7V (typ.)give:
Vin = 20.33V
Vout = 7.01 V
This confirms the very low remaining voltage across the device to be protected. It is also important to note that in this
approximation theparasitic inductance effect was not takeninto account. This could be few tenthsof volts during few ns at
the Vin side.This parasitic effect is notpresent at theVout side due the low current involved after the resistance R.
The measurements shown here after illustrate very clearly (Fig. A5a) the high efficiency of the ESDprotection :
- no influence of the parasitic inductanceson Vout stage
Please note that the EMIF02-600FU7 is not only acting for positive ESD surgesbut also for negative ones. For these kind
of disturbancesit clamps close to ground voltageas shown in Fig. A5b.
NOTE: DYNAMIC RESISTANCE MEASUREMENT
As thevalue ofthe dynamic resistance remainsstable for a
surge durationlower than 20µs,the 2.5µsrectangularsurge
is well adapted. In addition both rise and fall times are
optimized to avoid any parasitic phenomenon during the
measurement of Rd.
CROSSTALK BEHAVIOR
1- Crosstalkphenomena
FigA7 : Crosstalkphenomena
R
G1
V
G1
V
G2
R
G2
line 1
line 2
FigA6 : Rd measurementcurrentwave
I
I
PP
2 µs
2.5 µs
2.5µs duration measurement wave
R
L1
R
L2
α
V
G2
β
α
V
β
G1
V
G2
V
G1
tt
DRIVERSRECEIVERS
The crosstalk phenomena are due to the coupling between 2 lines. The coupling factor ( β12or β21) increases when the
gap across lines decreases, particularlyin silicondice. In the exampleabove the expected signal on load R
fact the real voltage at this point has got an extra valueβ21V
. This part of the VG1signal represents the effect of the
G1
isα2VG2,in
L2
crosstalk phenomenon of the line 1 on the line 2. This phenomenonhas to be taken into account whenthe drivers impose
fast digital data or high frequency analog signals in the disturbing line. The perturbed line will be more affected if it works
with low voltage signal or high load impedance (few kΩ). The following chapters give the value of both digital and analog
crosstalk.
Figure A8shows themeasurement circuit used toquantifythe crosstalk effect in a classicaldigital application.
Figure A9shows that in sucha conditionsignal from 0 to 5V and risetime of10 ns, the impact on thedisturbed line isless
than20mV peaktopeak. No datadisturbance was notedon the concernedline. Thesame results were obtained withfalling
edges.
Figure A10 gives themeasurement circuit for the analog application. In figure A11, the curveshows the effectof cell 1/24
on cell 2/23, no difference was foundwith othercouples of adjacentcells. In usual frequency range of analog signals (up to
100MHz) the effect on disturbed line is lessthan -32 dBm.
6/9
-70
-80
110100
F(MHz)
Page 7
PSPICEMODEL
FigA12: PSpicemodelofoneEMIF02-600F U 7cell
EMIF02-600FU7
5nH5nH
InputOutput
Dzin
1
Ω
FigureA12 shows thePSpice model of one cell ofthe EMIF02-600FU7.In thismodel, theclampingdiodes (Dzin andDzout)
are definedby the following PSpice parameters :
RS = 0.55
Cjo =100p
M = 0.3333
VJ = 0.6
BV =7
IBV = 1u
This model isavailable for frequencysimulation and for ambient temperature of 27°C.
The comparison betweenthe PSpicesimulation andthe measured frequency responseis given in figáA13. Thisshows that
the PSpice model is very close to the product behavior.
Informationfurnishedis believed to beaccurate andreliable. However, STMicroelectronics assumes no responsibility for theconsequences of
use of such informationnor for any infringementof patentsor otherrights of third parties which may resultfrom its use.No licenseis granted by
implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to
change without notice. This publicationsupersedes and replaces all informationpreviously supplied.
STMicroelectronics products are not authorized for use as criticalcomponents in life support devices or systems withoutexpress writtenapproval of STMicroelectronics.
The ST logois a registeredtrademark of STMicroelectronics
1998 STMicroelectronics - Printed inItaly - All rights reserved.
STMicroelectronics GROUP OF COMPANIES
Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco -
The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A.
http://www.st.com
9/9
Loading...
+ hidden pages
You need points to download manuals.
1 point = 1 manual.
You can buy points or you can get point for every manual you upload.