LCP22
Protection IC for ringing SLICs
Datasheet
−
production data
Description
The LCP22 has been developed to protect SLICs
operating on both negative and positive battery
supplies, as well as high voltage SLICs. It
provides crowbar mode protection for both TIP
and RING lines. The surge suppression is
assumed for each wire by two thyristor structures,
one dedicated to positive surges the second one
for negative surges. Both positive and negative
threshold levels are programmable by two gates.
LCP22 can be used to help equipment to meet
various standards such as UL1950, IEC 60950 /
CSAC22.2, UL1459 and TIA-968-A. LCP22
pinout and clearance is compatible with UL60950.
A Trisil
™
meets UL94 V0.
The LCP22 associated with Epcos PTC model
B59173C1130A151 is compliant with
ITU TK20/K21 (4 kV lightning and AC power fault
tests).
Figure 1. Functional diagram
Line (TIP or RING)
Features
•
Protection IC recommended for ringing SLICs
•
Wide firing voltage range: -120 V to +120 V
•
Low gate triggering current: I
G
= 5 mA max
•
Peak pulse current: I
PP
= 50 A (10/1000 µs)
•
Holding current: I
H
= 150 mA min.
Applications
•
Dual battery supply voltage SLICs
•
Central office (CO)
•
Private branch exchange (PBX)
•
Digital loop carrier (DLC)
•
Digital subscriber line access multiplexer
(DSLAM)
•
Fiber in the loop (FITL)
•
Wireless local loop (WLL)
•
Hybrid fiber coax (HFC)
•
ISDN terminal adapter
•
Cable modem
Gn
Gp
GND
Line (RING or TIP)
Figure 2. Pin-out configuration
G
n
NC
G
p
NC
Line (TIP or RING)
GND
GND
Line (RING or TIP)
TM: Trisil is a trademark of STMicroelectronics
October 2014
This is information on a product in full production.
Doc ID025775 Rev 3
1/10
www.st.com
Characteristics
LCP22
1
Characteristics
Table 1. Compliant with the following standards
Peak surge
voltage (V)
2500
1000
5000
1500
6000
4000
1500
8000
15000
4000
4000
1500
800
1000
Required
Voltage
peak
waveform
current (A)
2/10 µs
10/1000 µs
2/10 µs
2/10 µs
500
100
500
100
150
100
37.5
Current
waveform
2/10 µs
10/1000 µs
2/10 µs
2/10 µs
Minimum
series resistor
Rs to meet
standard (
Ω
)
12
10
24
0
35
10
0
0
0
14
0
20
15
0
Standard
GR-1089 Core First level
GR-1089 Core Second level
GR-1089 Core Intra-building
ITU-T-K20/K21
10/700 µs
5/310 µs
ITU-T-K20 (IEC61000-4-2)
IEC61000-4-5
TIA-968-A (formerly FCC part 68) type A
TIA-968-A (formerly FCC part 68) type B
1/60 ns
10/700 µs
1.2/50 µs
10/160 µs
10/560 µs
9/720 µs
ESD contact discharge
ESD air discharge
100
100
200
100
25
5/310 µs
8/20 µs
10/160 µs
10/560 µs
5/320 µs
Table 2. Absolute maximum ratings (T
amb
= 25 °C)
Symbol
Parameter
10/1000 µs
5/310 µs
2/10µs
t
p
= 0.2 s
t
p
= 1 s
t
p
= 15 min.
Value
50
80
150
11
7.5
3
-120 to 0
0 to +120
-55 to +125
-55 to +150
260
Unit
I
PP
Peak pulse current
A
I
TSM
Non repetitive surge peak on-state current (F = 50 Hz)
I
TSM
value specified for each line
I
TSM
value can be applied on both lines at the same time
(GND capability is twice the line I
TSM
)
Negative battery voltage range
Positive battery voltage range
Operating junction temperature range
Storage temperature range
Lead solder temperature (10 s duration)
A
V
Gn
V
Gp
T
j
T
stg
T
L
V
°C
°C
°C
2/10
Doc ID025775 Rev 3
LCP22
Figure 3. Pulse waveform
% I
PP
100
Characteristics
50
0
t
r
t
p
t
Table 3. Thermal resistance
Symbol
R
th(j-a)
Junction to ambient
Parameter
Value
150
Unit
°C/W
Table 4. Parameters related to the negative suppressor
Symbol
I
Gn
I
H-
V
DGL-
V
GnT
Parameter
Negative gate trigger current
Holding current (see
Figure 4)
Test conditions
V
Gn/GND
= -60 V
Measured at 50 Hz
V
Gn
= -60 V
R
s
= 25
Ω
R
s
= 25
Ω
150
Min.
Max. Unit
5
mA
mA
V
Gn/GND
= -60 V
Dynamic switching voltage Gn / TIP or
10/700 µs 2 kV
RING
(1)
1.2/50 µs 2 kV
G
n
to TIP voltage
I
Gn
= 20 mA
I
PP
= 30 A
I
PP
= 30 A
0.7
8
12
1.7
V
V
1. The V
DGL
value is the difference between the peak line voltage during the surge and the programmed gate voltage.
Table 5. Parameters related to the positive suppressor
Symbol
I
Gp
V
DGL+
V
GpR
Parameter
Positive gate trigger current
Test conditions
V
Gp/GND
= 60 V, measured at 50 Hz
R
s
= 25
Ω
R
s
= 25
Ω
Min. Max. Unit
5
mA
V
Gp/GND
= 60 V
Dynamic switching voltage Gp / TIP or
10/700 µs 2 kV
RING
(1)
1.2/50 µs
2 kV
G
P
to RING voltage
I
Gp
= -20 mA
I
PP
= 30 A
I
PP
= 30 A
1
8
20
2
V
V
1. The V
DGL
value is the difference between the peak line voltage during the surge and the programmed gate voltage.
Table 6. Parameters related to TIP or RING / GND
Symbol
I
R
C
Parameter
Reverse leakage current
Capacitance TIP or RING / GND
Test conditions
V
TIP or RING
= +120 V
V
TIP or RING
= -120 V
V
Gp/TIP or RING
= +1 V
V
Gn/TIP or RING
= -1 V
Min.
Max.
5
5
60
Unit
µA
pF
V
R
= -3 V, F =1 MHz, V
Gp
= 60 V, V
Gn
= -60 V
Doc ID025775 Rev 3
3/10
10
Characteristics
Table 7. Recommended gate capacitance
Symbol
C
n
, C
p
Component
Gate decoupling capacitance
Min.
100
Typ.
220
Max.
LCP22
Unit
nF
Figure 4. Relative variation of holding current versus junction temperature
IH[Tj] / IH[Tj=25 °C]
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40
-20
0
20
40
60
80
100
120
T (°C)
Figure 5. Maximum non repetitive surge peak on state current versus overload
duration
20
18
16
14
12
10
8
6
4
2
0
0.01
0.1
1
10
100
ITSM (A)
F = 50 Hz
Tj initial = 25 °C
t(s)
1000
Figure 6. Capacitance versus reverse applied voltage (typical values) with V
Gn
= -90 V
and V
Gp
= +90 V
C (pF)
70
line +
60
50
40
30
20
10
0
20
40
Vline (V)
60
80
100
line -
4/10
Doc ID025775 Rev 3
LCP22
Technical information
2
Technical information
Figure 7. LCP22 concept behavior
Rs
L1
IGn
T1
Gn
Th1
TIP
T2
Th2
Gp
V Tip
IGp
GND
-Vbat
Cn
+Vb
Cp
Rs
L2
RING
GND
V Ring
Figure 7
shows the classical protection circuit using the LCP22 crowbar concept. This
topology has been developed to protect two-battery voltage SLICs. It allows both positive
and negative firing thresholds to be programmed. The LCP22 has two gates (Gn and Gp).
Gn is biased to negative battery voltage -Vbat, while Gp is biased to the positive battery
voltage +Vb.
When a negative surge occurs on one wire (L1 for example), a current IGn flows through the
base of the transistor T1 and then injects a current in the gate of the thyristor Th1 which
turns-on. All the surge current flows through the ground. After the surge, when the current
flowing through Th1 becomes less negative than the negative holding current I
H-
, Th1
switches off. This holding current I
H-
is temperature dependent as per
Figure 4
When a positive surge occurs on one wire (L1 for example), a current IGp flows through the
base of the transistor T2 and then injects a current in the gate of the thyristor Th2 which
fires. All the surge current flows through the ground. After the surge, when the current
flowing through Th2 becomes less positive than the positive holding current I
H+
, Th2
switches off. This holding current I
H+
, typically 20 mA at 25 °C, is temperature dependent
and the same
Figure 4
also applies.
The capacitors Cn and Cp are used to speed up the crowbar structure firing during the fast
rise or fall edges. This allows minimization of the dynamic breakover voltage at the SLIC TIP
and RING inputs during fast surges. Please note that these capacitors are generally
available around the SLIC. To be efficient they have to be as close as possible to the LCP22
gate pins (Gn and Gp) and to the reference ground track (or plan). The optimized value for
Cn and Cp is 220 nF.
The series resistors Rs shown in
Figure 7
represent the fuse resistors or the PTCs which
are needed to withstand the power contact or the power induction tests imposed by the
country standards. Taking this factor into account, the actual lightning surge current flowing
through the LCP22 is equal to:
I surge = Vsurge / (Rg + Rs)
With
V surge = peak surge voltage imposed by the standard.
Rg = series resistor of the surge generator
Rs = series resistor of the line card (e.g. PTC)
Doc ID025775 Rev 3
5/10
10
单片机
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
