DALC208SC6 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'DALC208SC6' PDF : 10 Pages View PDF
DALC208
3
Crosstalk behavior
3.1
Crosstalk phenomena
Figure 13. Crosstalk phenomena
RG1
Line 1
VG1
RG2
Line 2
VG2
Crosstalk behavior
RL1
α1VG1 + β12VG2
RL2
α 2VG2 + β21VG1
DRIVERS
RECEIVERS
The crosstalk phenomenon is 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 in Figure 13 the expected signal on load RL2 is α2VG2, in fact the real voltage at this
point has got an extra value β21VG1. This part of the VG1 signal represents the effect of the
crosstalk phenomenon of line 1 on 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 disturbed line will be more affected if it works with low voltage signal or high load
impedance (few kΩ). The following sections give the value of both digital and analog
crosstalk.
3.2
Digital crosstalk
Figure 14. Digital crosstalk measurements
+5V
+5V
74HC04
Line 1
+5V
100nF
74HC04
Square
+5V
Pulse
Generator
5KHz
VG1
Line 2
β21 VG1
DALC208SC6
Figure 15. Digital crosstalk results
Figure 14 shows the measurement circuit used to quantify the crosstalk effect in a classical
digital application. Figure 15 shows that in such a condition: signal from 0 V to 5 V 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.
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