PBL38620-2 Datasheet, PDF (14/16 Pages) Ericsson – Subscriber Line Interface Circuit

PBL 386 20/2
K_R
+12 V /+5V
RING
TIP
VB2
VB
D_BB
D_VB
D_VB2
C _VB2
C_VB
R_F2
C_GG
R_P2
OVP
VB
R_F1
R_P1
E _RG
R₁
R_RT
R₂
C₁
C_HP
C_RC
C_TC
R_SG
C_LP
C₂
PBL 386 20/2
PTG
VTX
RRLY
AGND
HP
RSN
NC
NC
RINGX
REF
BGND
PLC
TIPX
POV
VBAT
PLD
VBAT2
VCC
PSG
NC
NC
DET
LP
C1
PLCC 28-PIN
DT _PACKAGE
C2
DR
C3
C _TX
R_T
R_R
R_REF
R _LC
R_OV
R_LD
VCC
R _TX
R_RX
R_B
R _FB
--
0
++
0
CODEC/
Filter
PBL 386 20/2
C _VCC
VCC
R₃ R₄
SLIC No. 2 etc.
SYSTEM CONTROL
INTERFACE
RESISTORS (Values according to IEC E96 series):
R
SG
=0Ω
1% 1/10 W
R_LD
= 49.9 kΩ 1% 1/10 W
R_OV
= User programmable
R_LC
= 38.3 kΩ 1% 1/10 W
R_REF = 49.9 kΩ 1% 1/10 W
R_R
= 64.9 kΩ 1% 1/10 W
R_T
= 105 kΩ 1% 1/10 W
R_TX
= 24.9 kΩ 1% 1/10 W
R_B
= 22.1 kΩ 1% 1/10 W
R
RX
= 52.3 kΩ 1% 1/10 W
R_FB
Depending on CODEC/filter
R₁
= 604 kΩ 1% 1/10 W
R₂
= 604 kΩ 1% 1/10 W
R₃
= 249 kΩ 1% 1/10 W
R₄
= 280 kΩ 1% 1/10 W
R_RT
= 330 Ω
5% 2 W
R_P1,
R
P2
≥ 10 Ω
1% 1/10 W (Note 1)
R_F1, R_F2 = Line resistor, 40 Ω 1%
CAPACITORS (Values according to IEC E96 series):
C
VB
C_VB2
C_VCC
C_TC
C_RC
C
HP
C_LP
C_TX
C_GG
C
1
C₂
DIODES:
= 100 nF
= 150 nF
= 100 nF
= 2.2 nF
= 2.2 nF
= 47 nF
= 150 nF
= 100 nF
= 220 nF
= 330 nF
= 330 nF
100 V 10%
100 V 10%
10 V 10%
100 V 10%
100 V 10%
100 V 10%
100 V 10%
10 V 10%
100 V 10%
63 V 10%
63 V 10%
D_VB
D_VB2
D_BB
= 1N4448
= 1N4448
= 1N4448
OVP:
Secondary protection (e. g. Power Innovations
TISPPBL2). The ground terminals of the secondary
protection should be connected to the common
ground on the Printed Board Assembly with a track
as short and wide as possible, preferable a
groundplane.
Note:
1) R_P1 and R_P2 may be omitted if D_VB is in place.
Figure 12. single-channel subscriber line interface with PBL 386 20/2 and combination CODEC/filter.
Overvoltage Protection
The PBL 386 20/2 SLIC must be protected
against overvoltages on the telephone line
caused by lightning, ac power contact and
induction. Refer to Maximum Ratings, TIPX
and RINGX terminals, for maximum
allowable continuous and transient currents
that may be applied to the SLIC.
Secondary Protection
The circuit shown in figure 12 utilizes series
resistors together with a programmable
overvoltage protector (e.g Power
Innovations TISPPBL2), serving as a
secondary protection.
The TISPPBL2 is a dual forward-conduc-
ting buffered p-gate overvoltage protector.
The protector gate references the protection
(clamping) voltage to negative supply
voltage (i.e the battery voltage,V_B ).
As the protection voltage will track the
negative supply voltage the overvoltage
stress on the SLIC is minimized.
Positive overvoltages are clamped to gro-
und by a diode. Negative overvoltages are
initially clamped close to the SLIC negative
supply rail voltage and the protector will
crowbar into a low voltage on-state
condition, by firing an internal thyristor.
A gate decoupling capacitor, C_GG, is needed
to carry enough charge to supply a high
enough current to quickly turn on the
thyristor in the protector. C_GG shall be placed
close to the overvoltage protection device.
Without the capacitor even the low
inductance in the track to the V_Bat supply will
limit the current and delay the activation of
the thyristor clamp.
The fuse resistors R_F serve the dual
purposes of being non- destructive energy
dissipators, when transients are clamped
and of being fuses, when the line is exposed
to a power cross.
If a PTC is choosen for R_F , note that it is
important to always use PTC´s in series
with resistors not sensitive to temperature,
as the PTC will act as a capacitance for fast
transients and therefore will not protect the
SLIC.
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