PBL 386 30/2
DC characteristics
A
A
B
C
B
C
D
D
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
Apparent battery VBat(@ IL = 0) =|VBat| - VOHvirt - RFeed · 4·10-3)
feedG = 2 · 25 Ω
60 · 103
B:
C:
RfeedB = 2 · 30 kΩ
R
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
lated according to
500
Loop Monitoring Functions
The widely varying environmental condi-
The loop current and ring trip detector
RLD
=
ILTh
tions in which SLICs operate may lead to
report their status through a common out-
the chip temperature limitations being ex-
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.
ceeded. The PBL 386 30/2 SLIC reduce
DET is selected via the two bit wide control
the dc line current when the chip tempera-
interface C1 and C2. Please refer to sec-
tion Control Inputs for a description of the
control interface.
ture reaches approximately 145°C and in-
creases it again automatically when the
temperature drops. Accordingly transmis-
Ring Trip Detector
sion is not lost under high ambient tem-
Ring trip detection is accomplished by con-
necting an external network to a compara-
tor in the SLIC with inputs DT and DR. The
ringing source can be balanced or unbal-
anced 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 driven
by the SLIC ring relay driver connects the
ringing source to tip and ring.
Loop Current Detector
perature 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
changes state is programmable by select-
ing the value of resistor RLD. RLD connects
between pin PLD and ground and is calcu-
14
ERICSSON [ ERICSSON ]
