Technical information
Figure 8.
USBUFxxW6
Remaining voltage at both stages S1 (Vinput) and S2 (Voutput) during
ESD surge
Vin
Vin
Vout
Vout
Positive surge
Negative surge
Please note that the USBUFxxW6 is not only acting for positive ESD surges but also for
negative ones. For these kinds of disturbances it clamps close to ground voltage as
shown in
(negative surge.
2.4
Latch-up phenomena
The early ageing and destruction of IC’s is often due to latch-up phenomenon which is
mainly induced by dV/dt. Thanks to its structure, the USBUFxxW6 provides a high immunity
to latch-up phenomenon by smoothing very fast edges.
2.5
Crosstalk behavior
Figure 9.
Crosstalk phenomenon.
R
G1
Line 1
V
G1
R
G2
Line 2
R
L1
α
1
V
G1
+
β
1 2
V
G2
V
G2
R
L2
α
2
V
G2
+
β
2 1
V
G1
DRIVERS
RECEIVERS
The crosstalk phenomenon is due to the coupling between 2 lines. The coupling factor (β
12
or
β
21
) increases when the gap across lines decreases, particularly in silicon dice. In the
example above the expected signal on load R
L2
is
α
2
V
G2
, in fact the real voltage at this point
has got an extra value
β
21
V
G1
. This part of the V
G1
signal represents the 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 kΩ).
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