CLP270M-TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
CLP270M-TR Datasheet PDF : 24 Pages
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CLP270M
Fig. 7a and 7b: Switching-on current versus Rsense.
ISWON (T, Rsense) / ISWON (25°C, 4 Ω)
2
@-20°C @25°C @75°C
1
Iswon @ 25°C (mA)
500
300
Iswon min Iswon max Iswon min Iswon max
negative negative positive positive
200
0.5
0.3
0.2
3
5
7
Rsense (Ω)
9 11 13
100
50
3
5
7
Rsense (Ω)
9 11
The operating point moves to region 5 for positive surges or region 6 for negative surges.
Once the surge current falls below the switching-off current ISWOFF, the CLP270M returns to its initial state
(region 4).
The choice of the switching-on currents is function of the Rsense resistors.
In normal operating condition the current (typically below -100 mA) should not activate the protection
device CLP270M. Therefore the level of activation is to be chosen just above this limit (-200 mA). This level
is adjusted through Rsense.
Figures 7a and 7b enable the designers to choose the right Rsense value.
EXAMPLE :
The choice of Rsense = 4 Ω ensures a negative triggering of -190 mA min and -320 mA max. In this case, the
positive triggering will be 150mA min and 280 mA max.
2.5. Failure Status
The CLP270M has an internal feature that allows the user to get a Failure Status (FS) indication. When the
CLP270M 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 provide a surge indication. It may also be used with a logic circuitry to
Fig. 8: Failure Status circuit and diagnostic.
Fig. 9 : Operation limits and destruction zone of
the CLP270M.
FAILURE
STATUS
Rsense
1
CLP270M
1k
+12V
Rsense
5 000
2 000
1 000
500
200
100
50
20
10
0.01 0.02
0.05 0.1 0.2
0.5
1
2
t (ms)
5
10
count the number of disturbances appearing on the lines.
If a surge exceeding the maximum ratings of the CLP270M occurs on the line, the device will fail in a
short-circuit state.
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