CLP200M Datasheet, PDF (7/21 Pages) STMicroelectronics – OVERVOLTAGE AND OVERCURRENT PROTECTION FOR TELECOM LINE

Fig. 7a and 7b : Switching-on current versus
RSENSE.
ISWON (mA)
500
300
-20°C 25°C 75°C
200
100
3
5
7
9 11 13
Rsense (Ω)
Iswon @ 25°C (mA)
500
Iswon min
negative
Iswon max
negative
Iswon min
posi tive
Iswon min
positive
300
200
CLP200M
2.5 . Failure Status
The CLP200M has an internal feature that allows
the user to get a Failure Status (FS) indication.
When the CLP200M is short-circuiting the line to
GND, a signal can be managed through pin 1. This
signal can be used to turn a LED on in order to pro-
vide a surge indication. It may also be used with a
logic circuitry to count the number of disturbances
appearing on the lines.
Fig. 8 : Failure Status circuit and diagnostic.
FAILURE
STATUS
Rse nse
1
CLP200M
1k
+12V
Rse nse
100
3
5
7
Rsense (Ω)
9 11
The choice of the switching-on current is function
of the R_SENSE resistors.
In normal operating condition, only the negative
current of the signal is of interest.This current (typi-
cally below -150 mA) should not activate the pro-
tection device CLP200M. Therefore the level of
activation is to be chosen just above this limit (typi-
cally -200 mA). This level is adjusted through
RSENSE.
Figures 7a and 7b enable the designers to choose
the right RSENSE value.
If a surge exceeding the maximum ratings of the
CLP200M occurs on the line, the device will fail in
a short-circuit state.
Fig. 9 : Operationlimits and destructionzone of the
CLP200M.
Ipp (A)
1000
100
10
0.01
0.1
1
10
t (ms)
EXAMPLE :
The choice of R_SENSE = 4 Ω ensures a negative
triggering of -220 mA min and -320 mA max. In this
case, the positive triggering will be 180mA min and
280 mA max.
The figure 9 shows two different curves :
The lower one indicates the maximum guaranted
working limits of the CLP200M.
The upper curve shows the limit above which the
CLP200M is completely destructed . In this case,
the Fail Diagnostic pin is on.
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