KBMF01SC6资料

®KBMF

EMI FILTER AND LINE TERMINATIONFOR PS/2 MOUSE OR KEYBOARD PORTS

IPAD™

MAIN APPLICATIONS

EMI Filter and line termination for mouse and key-board ports on:

■■■■

Desktop computersNotebooksWorkstationsServers

SOT23-6L(Plastic)Table 1: Order Code

Part Number

KBMF01SC6Figure 1: Functional Diagram+VccRsRpFEATURES

■Integrated low pass filters for Data and Clock lines

■Integrated ESD protection■Integrated pull-up resistors■Small package size

■Breakdown voltage: VBR = 6V min.DESCRIPTION

On the implementation of computer systems, theradiated and conducted EMI should be kept withinthe required levels as stated by the FCCregulations. In addition to the requirements ofEMC compatibility, the computing devices arerequired to tolerate ESD events and remainoperational without user intervention.

The KBMF implements a low pass filter to limit EMIlevels and provide ESD protection which exceedsIEC 61000-4-2 level 4 standard. The device alsoimplements the pull up resistors needed to biasthe data and clock lines. The package is theSOT23-6L which is ideal for situations whereboard space is at a premium.BENEFITS

■■■

MarkingKM1Dat InCCDat OutGnd+VccRsRp+VccClk InCCClk OutRsCode 01Tolerance39Ω±10%Rp4.7kΩ±10%C120pF±20%EMI / RFI noise suppression

ESD protection exceeding IEC61000-4-2 level 4High flexibility in the design of high density boards

COMPLIES WITH THE FOLLOWING ESD STANDARDS:

IEC 61000-4-2 (R = 330Ω C = 150pF)Level 4±15 kV (air discharge)

±8 kV (contact discharge)

MIL STD 883C, Method 3015-6Class 3C = 100pF R = 1500Ω

3 positive strikes and

3 negative strikes (F = 1 Hz)

TM: IPAD is a trademark of STMicroelectronics.

October 2004REV. 21/8

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KBMF

Table 2: Absolute Maximum Ratings (Tamb = 25°C)

SymbolVPPTjTstgTLTopPr

Parameter

ESD discharge R = 330W C = 150pF contact dischargeESD discharge - MIL STD 883 - Method 3015-6Junction temperatureStorage temperature range

Lead solder temperature (10 second duration)Operating temperature RangePower rating per resistor

Value±12±25150- 55 to +150

2600 to 70100

UnitkV°C°C°C°CmW

Table 3: Electrical Characteristics (Tamb = 25°C)

SymbolIRVBRVF

Parameters

Diode leakage currentDiode breakdown voltageDiode forward voltage drop

Test conditionsVRM = 5.0VIR = 1mAIF = 50mA

6

0.9

Min

Typ

Max10

UnitµAVV

TECHNICAL INFORMATION1. EMI FILTERING

The KBMFxxSC6 ensure a filtering protection against ElectroMagnetic and RadioFrequency Interferencesthanks to its low-pass filter structure. This filter is characterized by the following parameters :

- cut-off frequency- Insertion loss

- high frequency rejectionFigure2: Measurements configuration

Figure 3: KBMF attenuation curve

Insertion loss (dB)0-10RF IN50ΩTG OUTTEST BOARDKM1Vg50Ω-20-30-40110F (MHz)10010002/8

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2. ESD PROTECTION

The KBMFxxSC6 is particularly optimized to perform ESD protection. ESD protection is based on the useof device which clamps at:

Voutput = VBR + Rd.IPP

This protection function is splitted in 2 stages. As shown in figure 4, the ESD strikes are clamped by thefirst 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 Voutput level.Figure4: ESD clamping behaviorRgS1RdRsVinputVoutputS2RdVPPRloadDeviceto beprotectedVBRVBRESD SurgeKBMFxxSC6To have a good approximation of the remaining voltages at both Vinput and Voutput stages, we give thetypical dynamical resistance value Rd. By taking into account these following hypothesis : Rt>Rd, Rg>Rdand Rload>Rd, it gives these formulas:

Rg⋅VBR+Rd⋅Vg

Vinput=-----------------------------------------------------RgRs⋅VBR+Rd⋅Vinput

Voutput=----------------------------------------------------------------Rt

The results of the calculation done for VPP=8kV, Rg=330Ω (IEC 61000-4-2 standard), VBR=7V (typ.) andRd = 1Ω (typ.) give:

Vinput = 31.2 VVoutput = 7.8 V

This confirms the very low remaining voltage across the device to be protected. It is also important to notethat in this approximation the parasitic inductance effect was not taken into account. This could be fewtenths of volts during few ns at the input side. This parasitic effect is not present at the output side due thelow current involved after the resistance RS.

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

- Voutput clamping voltage very close to VBR (positive strike) and -VF (negative strike)

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Figure 5: Measurement conditionsESDSURGE16kVAirDischargeTEST BOARDKM1VinVoutFigure 6: Remaining voltage at both stages S1 (Vinput) and S2 (Voutput) during ESD surge

Negative surgePlease 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 bydV/dt. Thanks to its structure, the KBMF01SC6 provides a high immunity to latch-up phenomena bysmoothing very fast edges.

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4. CROSSTALK BEHAVIORFigure 7: Crosstalk phenomena

RG1Line 1VG1RG2Line 2RL1α1VG1+β12VG2VG2RL2α2VG2+β21VG1DRIVERSRECEIVERSThe 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 crosstalkmeasurements for monolithic device to guarantee negligeable crosstalk between the lines. In the exampleabove the expected signal on load RL2 is α2VG2, in fact the real voltage at this point has got an extra valueβ21VG1. This part of the VG1 signal represents the effect of the crosstalk phenomenon of the line 1 on theline 2. This phenomenon has to be taken into account when the drivers impose fast digital data or highfrequency analog signals in the disturbing line. The perturbed line will be more affected if it works with lowvoltage signal or high load impedance (few kΩ).Figure 8: Analog Crosstalk measurementsconfigurationFigure9:TypicalAnalogCrosstalk meas-urementcrosstalk (dB)0-2050ΩTG OUTTEST BOARDKM1RF IN-4050Ω-60-80-100-120110F (MHz)1001,000VgFigure 8 gives the measurement circuit for the analog crosstalk application. In figure 9, the curve showsthe effect of the Data line on the CLK line. In usual frequency range of analog signals (up to 100MHz) theeffect on disturbed line is less than -37dB.

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Figure 10: Digital crosstalk measurementsconfigurationFigure11:Digital crosstalk measurements

+5V74HC04Line 1SquarePulseGenerator5KHz+5VVG1Line 2+5V74HC04KBMF01SC6b21VG1Figure 10 shows the measurement circuit used to quantify the crosstalk effect in a classical digital appli-cation.

Figure 11 shows that in such a condition signal from 0 to 5V and rise time of few ns, the impact on theother line is less than 50mV peak to peak (below the logic high threshold voltage). The measurementsperformed with falling edges gives the results within the same range.5. APPLICATION EXAMPLE

Figure 12: Implementation of KBMFxxSC6 in a typical application

VccPS/2 ConnectorPS/2 KeyboardPS/2 MouseKDATKCLKKBMF01SC6Super I/OMDATMCLKKBMF01SC6The 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

DIMENSIONSREF.

A2AMillimetersMin.Typ.Max.0.10Min.00.9000.900.350.092.801.50

0.952.600.103.000.1020.600.00410°1.450.0351.300.0350.500.0140.200.0043.050.1101.750.059

InchesTyp.Max.0.0570.0040.0510.020.0080.1200.069

0.0370.1180.02410°A

DA1A2bCDEeHLθA1LbHθEceeFigure 14: SOT23-6L Foot print dimensions(in millimeters)

0.60Table 4: Mechanical Specifications

Lead platingLead plating thickness

Tin-lead5µm min.25µm max.Sn / Pb

(70% to 90%Sn)10µm maxMolded epoxyUL94V-0

1.203.502.300.951.10Lead materialLead coplanarityBody materialFlammability

Table 5: Ordering InformationOrdering codeKBMF01SC6

Table 6: Revision History

DateFeb-200328-Oct-2004

Revision1D2

Last update.

SOT23-6L package dimensions change for reference “D” from 3.0 millimeters (0.118 inches) to 3.05 millimeters (0.120 inches).

Description of Changes

MarkingKM1

PackageSOT23-6L

Weight16.7 mg

Base qty3000

Delivery modeTape & reel

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Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequencesof 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 grantedby implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subjectto change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are notauthorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners

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