L3000NSO 데이터 시트보기 (PDF) - STMicroelectronics
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L3000NSO
STMicroelectronics
L3000NSO Datasheet PDF : 32 Pages
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L3000N - L3092
Table 1.
Pin 13 of L3092
+3
(C1)
0
Pin 11 of L3000N
–3
+3
Stand-by
Not Used
Not Used
Pin 12 of L3092 Pin 12 of L3000N (C2)
0
Conversation
B.B
Ringing
–3
Not Used
Not Used
Not Used
c) Ringing (RING)
d) Boost Battery (BB),(see Appendix B).
The fifth status, Power down (PD), is set by the
output pin PDO of the L3092 that disconnect the
Bias Resistor, RH, of L3000N from ground.
The main difference between Stand-by and
Power down is that in SBY the power consump-
tion on the voltage battery VB– (– 48V) is reduced
but the L3000N DC Feeding and monitoring cir-
cuits are still active, in PD the power consumption
on VB- is reduced to zero, and the L3000N is
completely switched off.
SLIC OPERATING MODES
Through the L3092 Digital Interface it is possible to
select six different SLIC OPERATING MODES :
1) Conversation or Active Mode (CVS)
2) Stand - By Mode (SBY)
3) Power - Down Mode (PD)
4) Automatic Stand - By Mode (ASBY)
5) Test Mode (TS)
6) Ringing Mode (RNG)
1) CONVERSATION (CVS) OR ACTIVE MODE
This operating mode is set by the control proces-
sor when the Off hook condition has been recog-
nized,
As far as the DC Characteristic is concerned two
different feeding conditions are present :
a) Current limiting region : the DC impedance of
the SLIC is very high (> 20KΩ) and therefore the
system works like a current generator. By the
L3092 Digital Interface it is possible to selects the
value of the limiting current.:
60mA, 40mA or 25mA.
b) A standard resistive feeding mode : the charac-
teristic is equal to a battery voltage (VB-) minus
5V, in series with a resistor, whose value is set by
external components (see external component list
of L3092).
Switching between the two regions is automatic
without discontinuity, and depends on the loop re-
sistance. The SLIC AC characteristics are guar-
anteed in both regions.
Fig. 1 shows the DC characteristic in conversa-
tion mode.
Fig. 2 shows the line current versus loop resis-
tance for two different battery values and RFS =
200Ω.
The allowed maximum loop resistance depends
on the values of the battery voltage (VB), on the
RFS and on the value of the longitudinal current
(IGDK). With a battery voltage of 48V, RFS = 200Ω
and IGDK = 0mA, the maximum loop resistance is
over 3000Ω and with IGDK = 20mA is about
2000Ω (see Application Note on maximum loop
resistance for L3000N/L3092 SLIC KIT).
In conversation mode the AC impedance at the
line terminals is synthetized by the external com-
ponents ZAC and RP, according to the following
formula :
ZML
=
ZAC
25
+
2
⋅
RP
Depending the characteristic of the ZAC network,
ZML can be either a pure resistance or a complex
impedance. This allows for ST SLIC to meet dif-
ferent standards as far as the return loss is con-
cerned. The capacitor CCOMP guarantees stabil-
ity to the system.
The two to four wire conversion is achieved by
means of a circuit that can be represented as a
Wheatstone bridge, the branches of which being:
1) The line impedance (Zline).
2) The SLIC impedance at line terminals (ZML).
3) The balancing network ZA connected between
RX input and ZB pin of L3092.
4) The network ZB between ZB pin and ground
that shall copy the line impedance.
It is important to underline that ZA and ZB are not
equal to ZML and to Zline. They both must be
multiplied by a factor in the range of 10 to 25, al-
lowing use of smaller capacitors.
In case the L3000N/L3092 kit is used with a second
generation programmable COMBO (EG
TS5070FN) which is able to perform the two to four
wire conversion, the two impedances ZA and ZB
can be removed and the ZB pin connected to GND.
The -6dB Tx gain of the L3000N/L3092 SLIC kit in
fact allows to keep the echo signal always within
the COMBO Hybrid Balance Filter dynamic range.
In conversation mode, the L3000N dissipates
about 250mW for its own operation. The dissipa-
tion related to the current supplied to the line shall
be added, in order to get the total dissipation.
7/32
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