AN2064 데이터 시트보기 (PDF) - STMicroelectronics
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AN2064 Datasheet PDF : 14 Pages
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AN2064 - APPLICATION NOTE
The table 1 gives the main lightning standards.
Table 1: Main line card lightning surge standards
Country
Worldwide
Worldwide
Worldwide
Germany
Germany
USA
USA
France
Standard
ITU-T K20
IEC-61000-4-5
IEC-61000-4-5
VDE0433
VDE0878
GR-1089 Core (Telcordia)
GR-1089 Core (Telcordia)
I3124
Surge voltage
1500V
1000/4000V
1000/4000V
2000V
2000V
2500V
1000V
1000V
Waveform
10/700µs
10/700µs
1.2/50µs
10/700µs
1.2/50µs
2/10µs
10/1000µs
0.5/700µs
Current
37.5A
25/100A
25/100A
50A
50A
500A
100A
25A
Main worldwide standards for 50/60Hz overvoltage disturbances can be defined by two parameters: the
applied RMS voltage, between 60V and 1000V, and the test duration, between 0.2s and 15min.
From this section we can conclude that the TRISIL current capability must be adapted according to the
specific country (for example, a waveform surge of 100A for 10/1000µs for the US). As TRISIL are
dedicated to manage high currents for short duration surges (in the range of hundreds of ms) the 50/60Hz
disturbances test requirements show the need of a complementary protection stage, implemented with
series protection devices like fuses or positive temperature coefficient resistors (PTC).
2. Protection circuit
In the protection circuit we find particularities linked to the characteristics already mentioned in the TRISIL
selection section and also linked to the CO line interface. Generally the subscriber line interface circuit
(SLIC) is directly connected to the line without any isolation stage when operating in analog mode, while
in digital applications isolation is achieved using a transformer. Please note that, at the CO side,
protection is split into two areas - the primary protection stage located in the MDF and the secondary
protection directly soldered on the subscriber line card.
Figure 3: Analog line card protection circuit
PTC or Fuse
Tip
Subscriber line card
Relay
Rs1
TRISIL 1
TRISIL 2
-V bat
Rs2
SLIC
Ring
PTC or Fuse
TRISIL 1
TRISIL 2
Rs1
Rs2
Ring generator
Secondary protection, first stage Fuse or PTC and TRISIL 1, second stage TRISIL 2
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