CROSSTALK BEHAVIOR

1- Crosstalk phenomena

The crosstalk phenomena are due to the coupling

between 2 lines. The coupling factor (

β12 or β21)

increases when the gap across lines decreases,

particularly in silicon dice. In the example above

the real voltage at this point has got an extra value

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

Ω). The following chapters give

the value of both digital and analog crosstalk.

2- Digital Crosstalk

Figure A5 shows the measurement circuit used to

quantify the crosstalk effect in a classical digital

application.

Figure A6 shows that in such a condition: signal

from 0V to 5V and a rise time of 5 ns, the impact on

the disturbed line is less than 100mV peak to peak.

No data disturbance was noted on the concerned

line. The same results were obtained with falling

edges.

Note: The measurements have been done in the worst case i.e. on

two adjacent cells (I/O1 & I/O4).

Line 1

Line 2

DRIVERS

RECEIVERS

α

β

+

1

12

α

β

+

2

21

Fig. A4: Crosstalk phenomena.

DALC208SC6

100nF

+5V

Line 1

Line 2

+5V

+5V

74HC04

+5V

Square

Pulse

Generator

5KHz

74HC04

Fig. A5: Digital crosstalk measurements.

Fig. A6: Digital crosstalk results.

DALC208SC6

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