PBL 386 30/1
DC characteristics
A
A
B
C
B
C
D
D
[mA]
E
G
F
F
H
J
VTR [V]
|VBat| - VOHVirt - RFeed · (ILProg + 4·10-3)
A:
IL (@ VTR = 0V) = ILProg +
E:
F:
G:
H:
J:
IL ≈ 6 mA
60 · 103
Apparent battery VBat(@ IL = 0) =|VBat| - VOHvirt - RFeed · 4·10-3)
RfeedG = 2 · 25 Ω
B:
C:
RfeedB = 2 · 30 kΩ
103
RLC
ILConst(typ)= ILProg
=
- 4·10-3
VTROpen = |VBat| - VOH
VTR = |VBat| - VOHvirt - RFeed · (ILProg + 4·10-3)
Virtual battery VBatVirt (@ IL = 4 mA) = |VBat| - VOHVirt
RSG + 2 · 104
D:
RFeed =
200
Figure 12. Battery feed characteristics (without the protection resistors on the line).
Analog Temperature Guard
calculated according to
500
Loop Monitoring Functions
The widely varying environmental
The loop current and ring trip detector
RLD
=
ILTh
conditions in which SLICs operate may
report their status through a common out-
lead to the chip temperature limitations
put, DET. The detector to be connected to
The current detector is internally filtered
and is not influenced by the ac signal at the
two wire side.
being exceeded. The PBL 386 30/1 SLIC
DET is selected via the two bit wide control
reduce the dc line current when the chip
interfaceC1andC2.Pleaserefertosection
ControlInputsforadescriptionofthecontrol
interface.
temperaturereachesapproximately145°C
and increases it again automatically when
the temperature drops. Accordingly trans-
Ring Trip Detector
mission is not lost under high ambient
Ring trip detection is accomplished by
connecting an external network to a
comparator in the SLIC with inputs DT and
DR. The ringing source can be balanced or
unbalanced superimposed on VB or GND.
The unbalanced ringing source may be
applied to either the ring lead or the tip lead
with return via the other wire. A ring relay
drivenbytheSLICringrelaydriverconnects
the ringing source to tip and ring.
Loop Current Detector
temperature conditions.
The loop current detector is indicating
The detector output, DET, is forced to a
that the telephone is off hook and that
logic low level when the temperature guard
current is flowing in the loop by putting the
is active.
output DET to a logical low level when
selected.The loop current threshold value,
I
LTh, at which the loop current detector
changesstateisprogrammablebyselecting
the value of resistor RLD. RLD connects
between pin PLD and ground and is
4-206
ERICSSON [ ERICSSON ]
