stlc3040 STMicroelectronics, stlc3040 Datasheet - Page 6

• Manufacturer Part Number: stlc3040
• Description: Subscriber Line Interface Codec Filter, Cofislic
• Manufacturer: STMicroelectronics

STLC3040
In receive the maximum programmable gain is
0dB.
Gain step resolution in both sides (Rx and Tx) de-
pends on the value of the gains. See table below
to gain/step accuracy.
Table 2.
Tx: Xmax = 3dB; Rx: Xmax = 0dB
The Voice Signal Processing is shown in Block
diagram in Fig.3.
In the RX direction, after being decoded, the voice
sample passes through a set of interpolator and
correction filters. The signal is finally oversampled
to a high-rate of 256kHz before being summed to
the feed-back impedance synthesis signal.
Analog circuits performs Off-Hook sense and al-
lows On-Hook Signaling.
The longitudinal line current provided by the HV
(L3000N, L3000S, STLC3170) is sensed at pin IL;
Ground Key signalling is activated when the ab-
solute longitudinal current on IL pin exceeds
threshold. A low pass filter and programmable
persistance filter (register CR3) elaborates the
detection.
The Vbim pin receives from the HV (L3000N,
L3000S, STLC3170) an information on the actual
battery voltage (Vbim = Vbat/40), this voltage is
then compared with the line voltage and one bit is
set in the upstream data flow if Vline < (V
This allows the system to be tailored for different
line requirements.
Line and circuit-test functions are discussed in
detail in the appendix.
The HV (L3000N, L3000S, STLC3170) is driven
by the STLC3040 through two ternary pins C1
and C2 (pin 9 & 10 of STLC3040) that define the
operating state of the HV (L3000N, L3000S,
STLC3170) (Table 3).
C1 and C2 are set according to the content of the
bytes received by STLC3040 at DD pin (pin 5) of
the GCI Interface. C1 pin is internally tied to a
current-sensing circuit. It senses an extra current
that the HV (L3000N, L3000S, STLC3170) issues
when in thermal overload conditions.
6/49
Xmax - 6dB (1/128)
Xmax - 12dB (1/64)
Xmax - 18dB (1/32)
Xmax - 24dB (1/16)
Xmax - 30dB (1/8)
Xmax - 36dB (1/4)
Xmax - 42dB (1/2)
Tx & Rx Gain
Step accuracy
0.070dB
0.14dB
0.27dB
0.56dB
1.16dB
2.5dB
6.0dB
OL
/2).
Table 3:
PDO = 50 A
PDO = 0 A
(*) V
Through PDO pin (pin 28) the STLC3040 forces
the HV (L3000N, L3000S, STLC3170) in Power
Denial if the current at this pin is 0. When the
STLC3040 sinks 50 A the HV (L3000N, L3000S,
STLC3170) will be turned on. In Power Denial,
TIP and RING wires are disconnected from the
HV (L3000N, L3000S, STLC3170) driver (Power
Denial). Table 3 related to PDO = 0 A is valid
only for STLC3170.
VL1, VL2 pins sense, the Off-Hook when HV
(L3000N, L3000S, STLC3170) is in power denial,
allowing very low power consumption in On-Hook
condition.
Other important features, which usually require
external circuitry, like Test Tones, Ringing, Meter-
ing Impulse Injection are programmable via soft-
ware. Ring signals can be programmed both in
Amplitude and Frequency via CR9 register.
The Metering Pulse Injection Level can be set by
the CR10 register. Ring-Trip detection is per-
formed by a dedicated internal circuitry.
4.3 Slic Kit Operating Modes
STLC3040/HV (L3000N, L3000S, STLC3170) kit
can work in three main modes:
Each mode is selected by Command-Indicate
(C/I) and Monitor GCI channels. Line State
changes are signalled through either upstream
C/I or SR register. During the switching between
any two modes the indication is frozen for
10msec in addition to the programmed persis-
pin 10
(C2)
(C2)
pin
10
- POWER DOWN
- ACTIVE
- RING
hv
, V
(*)V
(*)V
(*)V
mv
(*)V
(*)V
(*)V
, V
mv
hv
lv
lv
mv
hv
lv
see digital interface electrical characteristics.
Ext. Indication Ext. Indication
Ext. Indication
Ext. Indication
CONV.NP
CONV.RP
(*)V
ST-BY
(*)V
hv
hv
pin 9 (C1)
Indication
Indication
TIP OPEN RING OPEN
pin 9 (C1)
(*)V
BB.NP
BB.RP
(*)V
Ext.
Ext.
mv
mv
(HV Internal
disconnect)
Loop Open
Indication
Indication
Resistors
RING NP
RING RP
(*)Vlv
(*)Vlv
Ext.
Ext.