smp100lc STMicroelectronics, smp100lc Datasheet - Page 5

• Manufacturer Part Number: smp100lc
• Description: Trisiltm For Telecom Equipment Protection
• Manufacturer: STMicroelectronics

SMP100LC
2
Figure 7.
100
10
1
1E-3
Z
th(j-a)
/R
1E-2
th(j-a)
Application information
In wireline applications, analog or digital, both central office and subscriber sides have to be
protected. This function is assumed by a combined series / parallel protection stage.
Figure 9.
In such a stage, parallel function is assumed by one or several Trisil, and is used to protect
against short duration surge (lightning). During this kind of surges the Trisil limits the voltage
across the device to be protected at its break over value and then fires. The fuse assumes
the series function, and is used to protect the module against long duration or very high
current mains disturbances (50/60Hz). It acts by safe circuit opening. Lightning surge and
mains disturbance surges are defined by standards like GR1089, FCC part 68, ITU-T K20.
Figure 10. Typical circuits
Variation of thermal impedance
junction to ambient versus pulse
duration (PCB - FR4, S
recommended pad layout)
1E-1
t (s)
p
Examples of protection stages for line cards
1E+0
Fuse TCP 1.25A
Typical circuit for subscriber side
Line
1E+1
Ex. Analog line card
Cu
= 35µm,
1E+2
SMP100LC-xxx
5E+2
T1
T2
Ring
relay
Figure 8.
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
C [V ] / C [V =2V]
1
Ring L
Tip L
Gnd
R
Fuse TCP 1.25A
Fuse TCP 1.25A
Typical circuit for central office side
Line
2
Ex. xDSL line card or terminal
Relative variation of junction
capacitance versus reverse voltage
applied (typical values)
R
5
10
V (V)
R
Application information
20
SMP100LC-xxx
SMP100LC-xxx
Tip S
Gnd
Ring S
50
100
V
T = 25°C
F =1MHz
RMS
j
= 1V
300
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