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Part: EMIF
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EMIF02-600FU7
10-BIT WIDE EMI FILTER INCUDING ESD PROTECTION
Application Specific Discretes A.S.D.T M
MAIN APPLICATIONS
Where EMI filtering in ESD sensitive equipment is required : C omputers and printers C ommunication systems M obile phones M CU Boards
DESCRIPTION
T he EMIF02-600FU7 is a highly integrated array designed to suppress EMI / RFI noise in all systems s ubjected to electromagnetic interferences. Additionally, this filter includes an ESD protection c ircuitry w hich prevents the protected device from destruction when s ubjected to ESD surges up to 15 kV. The EM IF02-600FU7 provides best efficiency when using s eparated inputs and outputs, in the so-called 4-points s tructure.
SSOP24
FUNCTIONAL DIAGRAM
BENEFITS
10-bit EMI bi-directional low-pass-filter Enhanced ESD protection for the protected device, optim ized by the four point structure H igh flexibility in the design of high density boards
. . . 10 C E L L S . . .
COMPLIES WITH THE FOLLOWING STANDARDS :
IEC 1000-4-2 15kV 8 kV (air discharge) (contact discharge)
ESD response to IEC1000-4-2 (15 kV air discharge)
Filtering response (with 50 l ine)
TM : A SD is trademark of S TMicroelectronics.
September 1998 - Ed: 2A
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EMIF02-600FU7
ABSOLUTE MAXIMUM RATINGS (Tamb = 25 °C) Symbol VPP Tj T op Tstg TL Parameter and test conditions ESD discharge IEC1000-4-2, air discharge ESD discharge IEC1000-4-2, contact discharge Junction temperature Operating temperature range Storage temperature range Lead solder temperature (10 second duration) Value 16 9 150 -40 to + 85 -55 to +150 260 Unit kV °C °C °C °C
ELECTRICAL CHARACTERISTICS (Tamb = 25 °C) Symbol VBR IRM VRM VC L Rd IPP RI/O Parameter Breakdown voltage Leakage current @ VRM Stand-off voltage Clamping voltage Dynamic impedance Peak pulse current Serial resistance between Input and Output
Symbol VBR IR M RI/O Rd IR = 1 mA VRM = 3V
Test conditions
Min. 6
Typ. 7
Max. 8 1
Unit V µA
Serial resistance between Input and Output Ipp = 10 A, t p = 2.5 µs (see note 1)
480
600 0.55
720
Note 1 : to calculate the ESD r esidual voltage, please refer to the paragraph "ESD PROTECT ION" on pages 4 & 5
Fig.1 : Relative variation of leakage current versus reverse voltage(Typical values)
IR[VR] / IR[VR=3V] 20.0 10.0 5.0
2.0 1.0 VR (V) 0.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5
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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 - Insertion loss - High frequency rejection
Fig A1 : EMIF02-600FU7 frequency response curve.
Figure A1 gives these parameters, in particular the signal rejection at the GSM frequency is about -20dBm at 900MHz, while the attenuation for FM broadcast range (around 100MHz) is better than -32dBm
Fig A2 : Measurement conditions
SPECTRUM ANALYSER
TG OUTPUT RF INPUT
50
EMIF02
Vg
TEST BOARD
Vin
Vout
50
EMIF02
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EMIF02-600FU7
ESD PROTECTION
In addition to its filtering function, the EMIF02-600FU7 is particularly optimized to perform ESD protection. ESD protection is based on voltage clamping w hich can be calculated by :
VCL = VB R + Rd.IPP
This protection function is splitted in 2 stages. As shown in figure A3, the ESD strikes are clamped by the first stage S1 and then its remaining overvoltage is applied to the second stage through the resistor R. Such a configuration makes the output voltage Vout very low.
Fig A3 : ESD clamping behavior
Rg R
ESD Surge
Rd Vg Vin Vbr
Rd Vout Vbr Rload
S1 EMIF02-600FU7
S2 Device to be protected
To have a good approximation of the remaining voltages at both Vin and Vout stages, we provide the typical dynamical resistance value Rd. By taking into account these following hypothesis : R>>Rd, RG>> Rd and Rload>>Rd, it gives these formulas:
Vin =
Rg.Vbr+Rd.Vg Rg
Vout =
R.Vbr+Rd.Vin R
The results of the calculation done for VG=8kV, RG= 330 (IEC1000-4-2 standard) and VBR=7V (typ.) give:
Vin = 20.33 V 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 the parasitic inductance effect was not taken into account. This could be few tenths of volts during few ns at the Vin side. This parasitic effect is not present at the Vout 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 ESD protection : - no influence of the parasitic inductances on Vout stage - Vout clamping voltage very close to VBR
Fig A4 : Measurement conditions
LOW-PASS FILTER
Vin
Vout
GND
GND
GND
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EMIF02-600FU7
Fig A5 : Remaining voltage at both stages S1 (Vin) and S2 (Vout) during ESD surge
a) Positive surge
b) Negative surge
Please note that the EMIF02-600FU7 is not only acting for positive ESD surges but also for negative ones. For these kind of disturbances it clamps close to ground voltage as shown in Fig. A5b. NOTE: DYNAMIC RESISTANCE MEASUREMENT As the value of the dynamic resistance r emains stable for a surge duration lower than 20µs, the 2.5µs rectangular surge is well adapted. In addition both rise and fall times are optimized to avoid any parasitic phenomenon during the measurement of Rd.
Fig A6 : Rd measurement current wave
I
IPP
t 2 µs 2.5 µs 2.5µs duration measurement w ave
CROSSTALK BEHAVIOR 1- Crosstalk phenomena Fig A7 : Crosstalk pheno mena
RG1 line 1 VG1 VG2
VG1 RG2 line 2
RL1
VG2
RL2
VG2
VG1
DRIVERS
RECEIVERS
The crosstalk phenomena are due to the coupling between 2 lines. The coupling factor ( 12 or 21 ) increases when the gap across lines decreases, particularly in silicon dice. In the example above the expected signal on load RL2 is 2VG2, in fact the real voltage at this point has got an extra value 21VG1. This part of the VG1 signal represents the effect of the crosstalk phenomenon of the line 1 on the line 2. This phenomenon has to be taken into account when the 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 k) . The following chapters give the value of both digital and analog crosstalk. 5/9
Others parts begin by em
EM-1 EM-2 EM-3 EM-4 EM-5 EM-6 EM-7
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