ST AN1783 APPLICATION NOTE 数据手册

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HOW TO MAKE FIRE-WIRE COMMUNICATION PORT SAFE?
October 2003-Ed:1P.MERCERON
Video-media equipment growth has lead manufacturers to use fast transmission buses in order to share in-formation quickly and easily.
In many cases,video equipment use Fire-Wire link (IEEE1394)which brings the following features:n Up to 63devices can be plugged on the bus n 400Mb/s data transmission rate n Hot plugging
n Power through the cable n Plug-and-play n Low cost cabling
n
Low implementation cost
As a matter of fact,this race for fast transmission and small compact video machines (cameras,mobiles,video equipment)has brought more and more integrated and sensitive electronic devices at the same time.As a result,on one hand,protection devices have been required to make the system more robust regarding ESD while,on the other hand,line adaptation have been implemented to prevent fast signal distortion due to high data rate transmission across non ideal elements.Fig.1:ST1394-01SC6internal diagram.
ST1394-01SC6is one of those devices that com-bine both ESD protection and line termination at a time in one chip especially designed for Fire-Wire transmission.
Its ±4kV ESD IEC61000-4-2compliance and small package (1.5x2.8mm)makes it very conve-nient for IEEE1394link.
The following internal diagram gives an idea of its characteristics.
We can notice on figure 1the following points:n ESD protection is performed with clamping diodes located at each line side.
n RC elements realize line termination at each data lines
n
Moreover,intrinsic clamping diode capacitors offers RF rejection for GSM bandwidth.
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voltage at ST1394-01SC6input terminations when -4kV is V1
voltage at ST1394-01SC6terminations when +4kV show the remaining over voltage at the ST1394-01SC6output efficient protection against ±4kV ESD strike.
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frequency behavior is monitored and typical
one ST1394-01SC6device manages two considered.This phenomenon could be explained undesirable coupling elements like parasitic Cross-talk analysis consists in checking the impact communication.The test set-up schematic
VNA Port 1Rg
15:Cross-talk set-up.
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This is not all,by the way the VNA:it needs to be calibrated before the measurements are performed.This imposes the use of a special calibration board previously set-up the analyzer and provides it the test PCB characteristics.Those latter would be subtracted to the final measurements.
Typical calibration board developed for the ST1394-01SC6frequency response board measurement given in figure18.
Once"Full two port"calibration is performed on equipment,the ST1394-01SC6frequency response analysis can be done.。