USBLC6-2

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3. HOW TO ENSURE A GOOD ESD PROTECTION

While the USBLC6-2 provides a high immunity to ESD surge, an efficient protection depends on the layout

phenomena (see figure 6).

It’s often harder to connect the power supply near to the USBLC6-2 unlike the ground thanks to the ground

plane that allows a short connection.

To ensure the same efficiency for positive surges when the connections can’t be short enough, we

from these kinds of overvoltage disturbances (see figure 7).

The add of this capacitance will allow a better protection by providing during surge a constant voltage.

The figures 8, 9 and 10 show the improvement of the ESD protection according to the recommendations

described above.

IMPORTANT:

A main precaution to take is to put the protection device closer to the disturbance source (generally the

connector).

Note: The measurements have been done with the USBLC6-2 in open circuit.

Figure 7: ESD behavior: optimized layout and

add of a capacitance of 100nF

Figure

8:

ESD

behavior:

measurements

conditions (with coupling capacitance)

Figure

9:

Remaining

voltage

after

the

USBLC6-2 during positive ESD surge

Figure

10:

Remaining

voltage

after

the

USBLC6-2 during negative ESD surge

REF1=GND

VI/O

ESD

SURGE

I/O

REF2=+

C=100nF

Lw

V+

V

CL

CC

F

V+

=

surge >0

surge <0

VV

CL

F

-

- =

t

V+

CL

POSITIVE

SURGE

t

V-

CL

NEGATIVE

SURGE

+5V

C=100nF

TEST BOARD

ESD

SURGE

Vin

Vout

Vin

Vout