Datasheet KBMF Datasheet (ST)

®
EMI FILTER AND LINE TERMINATION
IPAD™
MAIN APPLICATIONS
EMI Filter and line termination for mouse and key­board ports on:
Desktop computers
Notebooks
Workstations
Servers
FOR PS/2 MOUSE OR KEYBOARD PORTS
KBMF
FEATURES
Integrated low pass filters for Data and Clock
lines
Integrated ESD protection
Integrated pull-up resistors
Small package size
Breakdown voltage: V
= 6V min.
BR
DESCRIPTION
On the implementation of computer systems, the radiated and conducted EMI should be kept within the required levels as stated by the FCC regulations. In addition to the requirements of EMC compatibility, the computing devices are required to tolerate ESD events and remain operational without user intervention. The KBMF implements a low pass filter to limit EMI levels and provide ESD protection which exceeds IEC 61000-4-2 level 4 standard. The device also implements the pull up resistors needed to bias the data and clock lines. The package is the SOT23-6L which is ideal for situations where board space is at a premium.
SOT23-6L
(Plastic)
Table 1: Order Code
Part Number Marking
KBMF01SC6 KM1
Figure 1: Functional Diagram
+Vcc
Dat In
Gnd
Clk In
Rs
CRpC
+Vcc
Rs
CRpC
Rs Rp C
Code 01 39 4.7kΩ 120pF
Tolerance ±10% ±10% ±20%
Dat Out
+Vcc
Clk Out
BENEFITS
EMI / RFI noise suppression
ESD protection exceeding IEC61000-4-2 level 4
High flexibility in the design of high density
boards
TM: IPAD is a trademark of STMicroelectronics.
COMPLIES WITH THE FOLLOWING ESD STANDARDS:
IEC 61000-4-2 (R = 330 C = 150pF)
Level 4 ±15 kV (air discharge)
±8 kV (contact discharge)
MIL STD 883C, Method 3015-6
Class 3 C = 100pF R = 1500
3 positive strikes and 3 negative strikes (F = 1 Hz)
REV. 2
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KBMF
Table 2: Absolute Maximum Ratings (T
amb
= 25°C)
Symbol Parameter Value Unit
V
PP
T
j
T
stg
T
L
T
op
P
r
ESD discharge R = 330W C = 150pF contact discharge ESD discharge - MIL STD 883 - Method 3015-6
Junction temperature 150 °C
Storage temperature range - 55 to +150 °C
Lead solder temperature (10 second duration) 260 °C
Operating temperature Range 0 to 70 °C
Power rating per resistor 100 mW
Table 3: Electrical Characteristics (T
amb
= 25°C)
±12 ±25
kV
Symbol Parameters Test conditions Min Typ Max Unit
I
R
V
BR
V
F
Diode leakage current
Diode breakdown voltage
Diode forward voltage drop
= 5.0V
V
RM
= 1mA
I
R
= 50mA
I
F
10 µA
6V
0.9 V
TECHNICAL INFORMATION
1. EMI FILTERING
The KBMFxxSC6 ensure a filtering protection against ElectroMagnetic and RadioFrequency Interferences thanks to its low-pass filter structure. This filter is characterized by the following parameters :
- cut-off frequency
- Insertion loss
- high frequency rejection
Figure 2: Measurements configuration Figure 3: KBMF attenuation curve
Insertion loss (dB)
0
-10
-20
-30
-40 1 10 100 1000
F (MHz)
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TG OUT
50
Vg
TEST BOARD
KM1
RF IN
50
KBMF
2. ESD PROTECTION
The KBMFxxSC6 is particularly optimized to perform ESD protection. ESD protection is based on the use of device which clamps at:
V
= VBR + Rd.I
output
This protection function is splitted in 2 stages. As shown in figure 4, 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 very low at the V
Figure 4: ESD clamping behavior
PP
output
level.
Rg
V
PP
ESD Surge
To have a good approximation of the remaining voltages at both V
V
Rd
BR
S1
Rs
Vinput
Voutput
KBMFxxSC6
S2
Rd
V
input
BR
and V
Rload
Device
to be
protected
stages, we give the
output
typical dynamical resistance value Rd. By taking into account these following hypothesis : R and R
load>Rd
, it gives these formulas:
V
V
input
output
RgV
=
RsV
=
-----------------------------------------------------------------
BRRdVg
-----------------------------------------------------­R
g
BRRdVinput
R
t
+
+
t>Rd
, Rg>R
d
The results of the calculation done for V R
= 1 (typ.) give:
d
V
input
V
output
= 31.2 V
= 7.8 V
=8kV, Rg=330 (IEC 61000-4-2 standard), VBR=7V (typ.) and
PP
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 input side. This parasitic effect is not present at the output side due the low current involved after the resistance R
.
S
The measurements done here after show very clearly (figure 6) the high efficiency of the ESD protection :
- no influence of the parasitic inductances on output stage
- V
clamping voltage very close to VBR (positive strike) and -VF (negative strike)
output
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KBMF
Figure 5: Measurement conditions
ESD
SURGE
16kV
Air
Discharge
TEST BOARD
KM1
Vin
Vout
Figure 6: Remaining voltage at both stages S1 (V
) and S2 (V
input
) during ESD surge
output
Positive surge Negative surge
Please note that the KBMF01SC6 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 the Negative Surge figure.
3. LATCH-UP PHENOMENA
The early ageing and destruction of IC’s is often due to latch-up phenomena which is mainly induced by dV/dt. Thanks to its structure, the KBMF01SC6 provides a high immunity to latch-up phenomena by smoothing very fast edges.
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4. CROSSTALK BEHAVIOR
Figure 7: Crosstalk phenomena
R
G1
V
G1
R
G2
V
G2
Line 1
Line 2
KBMF
R
L1
R
L2
αβ
αβ
V+ V
1G1 12G2
V+ V
2G2 21G1
DRIVERS
RECEIVERS
The crosstalk phenomena is due to the coupling between 2 lines. The coupling factor ( β12 or β21 ) increases when the gap across lines decreases, this is the reason why we provide crosstalk measurements for monolithic device to guarantee negligeable crosstalk between the lines. In the example above the expected signal on load R
β
. This part of the VG1 signal represents the effect of the crosstalk phenomenon of the line 1 on the
21VG1
is α2VG2, in fact the real voltage at this point has got an extra value
L2
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 kΩ).
Figure 8: Analog Crosstalk measurements configuration
TG OUT
50
Vg
TEST BOARD
KM1
RF IN
50
Figure 9: Typical Analog Crosstalk meas­urement
crosstalk (dB)
0
-20
-40
-60
-80
-100
-120 1 10 100 1,000
F (MHz)
Figure 8 gives the measurement circuit for the analog crosstalk application. In figure 9, the curve shows the effect of the Data line on the CLK line. In usual frequency range of analog signals (up to 100MHz) the effect on disturbed line is less than -37dB.
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KBMF
Figure 10: Digital crosstalk measurements
Figure 11:Digital crosstalk measurements
configuration
+5V +5V
Square Pulse Generator 5KHz
+5V
74HC04
Line 1
V
G1
Line 2
KBMF
01SC6
74HC04
b
V
21
G1
Figure 10 shows the measurement circuit used to quantify the crosstalk effect in a classical digital appli­cation. Figure 11 shows that in such a condition signal from 0 to 5V and rise time of few ns, the impact on the other line is less than 50mV peak to peak (below the logic high threshold voltage). The measurements performed with falling edges gives the results within the same range.
5. APPLICATION EXAMPLE Figure 12: Implementation of KBMFxxSC6 in a typical application
KDAT
KCLK
KBMF
01SC6
Vcc
PS/2 Connector
PS/2 Keyboard
Super I/O
MDAT
KBMF
MCLK
01SC6
PS/2 Mouse
The KBMF01SC6 device could be used on PS/2 mouse or keyboard as indicated by figure 12.
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Figure 13: SOT23-6L Package Mechanical Data
A2
A
D
A1
L
H
θ
c
E
b
ee
KBMF
DIMENSIONS
REF.
A 0.90 1.45 0.035 0.057
A1 0 0.10 0 0.004
A2 0.90 1.30 0.035 0.051
b 0.35 0.50 0.014 0.02
C 0.09 0.20 0.004 0.008
D 2.80 3.05 0.110 0.120
E 1.50 1.75 0.059 0.069
e 0.95 0.037
H 2.60 3.00 0.102 0.118
L 0.10 0.60 0.004 0.024
θ 10° 10°
Millimeters Inches
Min. Typ. Max. Min. Typ. Max.
Figure 14: SOT23-6L Foot print dimensions
Table 4: Mechanical Specifications
(in millimeters)
Lead plating Tin-lead
0.60
5µm min.
25µm max.
Sn / Pb
(70% to 90%Sn)
3.50
2.30
0.95
1.20
1.10
Lead plating thickness
Lead material
Lead coplanarity 10µm max
Body material Molded epoxy
Flammability UL94V-0
Table 5: Ordering Information
Ordering code Marking Package Weight Base qty Delivery mode
KBMF01SC6 KM1 SOT23-6L 16.7 mg 3000 Tape & reel
Table 6: Revision History
Date Revision Description of Changes
Feb-2003 1D Last update.
28-Oct-2004 2 SOT23-6L package dimensions change for reference “D”
from 3.0 millimeters (0.118 inches) to 3.05 millimeters (0.120 inches).
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KBMF
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is 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 publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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All other names are the property of their respective owners
© 2004 STMicroelectronics - All rights reserved
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