STLC3080 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC3080' PDF : 23 Pages View PDF
Figure b. STLC3080 DC Characteristic in
Active Mode.
I
ILIM [20÷50mA]
RFEED =
RDC
5
+2RP
RFEED = 2RP
VBAT
V
VBAT -7.8V
Resistive Region is programmable by means of
external resistor RDC, limiting current can be se-
lected by RLIM resistor.
Concerning AC characteristic the STLC3080 allows
to set 2W termination impedance by means of one
external scaled impedance that may be complex.
Two to four wire conversion is provided by an exter-
nal network. Such network can be avoided in case
of application with COMBOII, in this case the two to
four wire conversion is implemented inside the
COMBOII by means of the programmable Hybal fil-
ter.
When in ACTIVE mode it is also possible to per-
form battery reversal in soft mode (with program-
mable transition time) without affecting the AC sig-
nal transmission.
Ringing
When Ringing mode is selected the STLC3080
activates the ring relay injecting the ringing signal
on the line. As the ring trip is detected the logic in-
dicator DET is set low and the ringing is automat-
ically disconnected without waiting for the card
controller command (auto ring trip).
DET remains latched Low untill the operative
mode is modified.
If required , the ringing relay drive signal RELR
can be synchronised to a clock applied to
CKRING input.
This clock is derived from the ringing signal with
proper time delay, according to the activation/de-
activation time of the relay.
RELR is activated on the low level of CKRING
clock. The duty cycle of CKRING can be modified
in order to activate the RELR when required:
CKRING low must last 1µs minimum.
If the synchronisation is not required, CKRING in-
put must be steadily kept Low.
All the STLC3080 relay drivers are open drain
with the source connected to the RGND pin. Each
relay drivers integrates a protection structure that
allows to avoid external kick - back diodes, using
both 5V or 12V relays.
The ring trip circuit and its behaviour is described
in Appendix D.
STLC3080
Ground Start.
This mode is selected when the SLIC is adopted
in a system using the Ground Start feature. In this
mode the TIP termination is set in High Imped-
ance (100kΩ) while the RING one is active and
fixed at Vbat +4.8V. In the case of connection of
RING termination to GND the sinked current is
limited to 30mA. When RING is connected to
GND both Off-Hook and Ground-Key detectors
become active. Power dissipation in this mode
with a -48V battery voltage is 100mW
High Impedance Feeding.
As Stand-By, this mode is set in On-Hook condi-
tion, with further reduced power consumption.
Higher power efficiency turns back a lower immu-
nity of the Off-Hook detector to line common
mode currents.
The DC feeding shows a constant current charac-
teristic (Ilim = 17mA) followed by a resistive range
with an equivalent series resistance RFEED =
1600Ω + 2Rp.
Thermal protection circuit is still active, preventing
the junction temperature, in case of fault condi-
tion, to exceed 150°C
In High Impedance Feeding most of the circuit is
switched off, only the circuit, dedicated to Off-
Hook detection, is powered. This allows to reduce
the total power consumption in On-hook to 30mW
(typical).
The Off-Hook detection threshold is not program-
mable but defined at a fixed IDETHI = 8mA(max.)
Figure c. STLC3080 DC Characteristic in High
Impedance Feeding
I
17mA
RFEED = 1600Ω +2RP
D98TL373
V
VBAT -0.8V
5/23
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