STLC3080 STMicroelectronics, STLC3080 Datasheet - Page 7

• Manufacturer Part Number: STLC3080
• Description: IC INTERFACE LINE SUBSCRB 44TQFP
• Manufacturer: STMicroelectronics

Specifications of STLC3080

• Function: Subscriber Line Interface Concept (SLIC)
• Number Of Circuits: 1
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 5.5mA
• Power (watts): 1.1W
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-LQFP
• Includes: Automatic Activation Mode, BORSCHT Functions, Ring Trip Detection, Slave Mode
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

- High Impedance Feeding :
entered after a Power-On Reset or 1XX word, this
status is set during steady On/Hook condition;
most of the circuitry is idle and only a low power
Off-Hook detection circuit is kept alive.
Direct Polarity only is assumed , independently of
the selected one.
To minimise the power consumption the Off-Hook de-
tection circuit has low common mode current rejection.
- Stand by
Notice that in Stand-By state the Off-Hook detec-
tor is sensitive only to the transversal component
of the line current with high immunity to common
mode disturbances; this performance implies an
increasing in power consumption: for that reason
Stand-By is not used as a quiescent state.
- Active state gets operative for conversation af-
ter
Stand-By state, set after any Off-Hook detected in
High Impedance Feeding.
If the Off-Hook condition is confirmed in Stand By,
Active mode is set ; if not (in case of spurious de-
tection), false activation is prevented, and High
Impedance Feeding is resumed.
In order to have the device falling back in HI-feed-
ing mode after the line is back in on-hook condi-
tion. It is necessary to select as input state the ac-
tive direct polarity mode (default).
During Active state On/Off-Hook status will af-
fect in real time DET signalling bit.
In order to allow Pulse-Mode Dialling, once Ac-
tive state is set, it cannot be changed by fast On-
Hook , but it is turned back to High Impedance
Feeding
longer than 128 x CKRING period.
Automatic activation (and deactivation) is based
on an internal state-machine which is clocked by
a free running internal oscillator.
A detailed description is reported in the Appendix A.
DUAL BATTERY CONFIGURATION
STLC3080 is also meant for low power consump-
tion systems using Dual Battery solution. It is suf-
ficient to connect the collector of the external tran-
sistor, through a diode, to the reduced battery
(see Fig. 2 for single battery solution and Fig. 3
for dual battery solution). The activation of the
batteries is automatic, only depending on the DC
load at the RING and TIP terminals; no controllers
action is required.
PROTECTION CIRCUIT
- Suggested protection circuit is based on pro-
grammable Trisils (like LCP1511/2) as shown
in Fig.2 and Fig. 3, and the surge current is
limited by the resistors RPT2 and RPR2, which
are PTC types , protecting the device against
an Off-Hook validity check performed in
only if an On-Hook condition
lasts
- Additionally, STLC3080 is provided with the
When the current injected into PCD exceeds a
threshold of 320 A (+/- 30%) , DET and GDK/AL
are set Low signalling a fault condition. No
change on the SLIC mode is performed.
Voltage threshold is defined by proper value of
the series resistors (see Fig.1)
Figure 1.
This circuit gives the possibility to protect the de-
vice against power crosses through a relay in-
stead of PTCs; once the fault condition is de-
tected
disconnecting the Slic from the line terminals.
METERING PULSE INJECTION
STLC3080 provides external pins and compo-
nents for Metering Pulse injection. TTXIN pin is
the input for the 12kHz or 16kHz Metering Pulse
injection. This pin also provides a DC constant
current source that is injected into the external
RDA resistor (typ. 10k
200 ) connected between TTXIN pin and AGND.
The voltage drop across TIP and RING line ampli-
fiers and, consequentally the AC swing available.
When Metering Pulse injection is not used and
voltage drop is not required, TTXIN must be
shorted to AGND and RTTX, RDA and CTTX ex-
ternal components must be removed. The TTX
cancellation is obtained through an external
RTTX and CTTX network connected between
TTXIN and CAC pins.
Fault detection
The device provides current sense on TIP and
RING wires that allow to detect longitudinal DC
current (I
higher than a threshold (see detectors table in-
side electrical characteristics) a fault indication is
provided on DET and GDK pin (both outputs be-
come low). The fault indication is active till the
fault cause persists. With this circuit the following
fault condition can be detected.
TIP
TIP
RING to VB1
RING to GND
RING to TIP to VB1
RING
TIP
both lightning and power-cross.
PCD input to directly monitor overvoltages ap-
plied to the line wires.
to VB1
to GND
R
R
the
LL
PCD
). When this I
controller
VCC
to obtain 2.2Vrms on
LL
drives
current becomes
Ith
STLC3080
this
D98TL385
DET
GDK/AL
CSOUT
relay
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