l3037 STMicroelectronics, l3037 Datasheet - Page 7

• Manufacturer Part Number: l3037
• Description: Subscriber Line Interface Circuit
• Manufacturer: STMicroelectronics

CONTROL INTERFACE
(*) LIM = 0
TIP OPEN MODE (TO)
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 Impedan-
ce (100Kohm) while the RING termination is acti-
ve and fixed at Vbat + 4.5V. In the case of con-
nection of RING termination to GND the sinked
current is limited to 30mA. When RING is connec-
ted to GND both off-hook and ground-key detec-
tors become active.
Power dissipation in this mode with a -48V battery
voltage is 100mW (including the power dissipa-
tion from +5/-5V supply).
POWER DOWN MODE (PD)
In this mode, both TIP and RING terminations are
open and no current is fed into the line.
The power dissipation is very low.
This mode is usually selected in emergency con-
dition or when the connected line is disabled.
This is also the mode into which the SLIC is auto-
matically forced, in the case of thermal overload
T
RINGING MODE (RNG)
When this mode is selected the ringing signal is
injected on the line via the ext relay activated by
the L3037 relay driver.
When the ringing signal phase is provided at the
RGIN pin, the relay command is also synchroni-
zed with the ringing signal zero crossing.
The TIP and RING termination of the L3037 are
senses the line current which is then integrated
on the CRT capacitor.
TIP pin voltage is fixed at – 2.5V, RING pin volt-
age is fixed at V
rent capability is limited to 100mA.
When off-hook occurs during ringing burst the
voltage on CRT increase above a proper thre-
shold and ring trip is detected.
j
> 150 C typ.
D0
0
1
1
1
1
0
0
0
I
D1
lim
0
1
1
0
0
1
0
1
INPUTS
= 25mA; LIM = H. I. (open)
BAT
GST
0
0
1
0
1
0
1
1
+ 4.5V, TIP, RING buffer cur-
X (*)
X (*)
LIM
X
X
X
X
X
X
POWER DOWN
STANDBY D. P.
STANDBY R. P.
ACTIVE D. P.
ACTIVE R. P.
RING
A. OPEN
RESERVED
I
lim
= 44mA; LIM = 1
OPERATING MODE
I
lim
Once ring trip is detected the ringing signal is
automatically disconnected at the first zero cros-
sing. When the ringing signal phase is not provi-
ded at the RGIN pin the ringing signal is discon-
nected immediately after ring trip detection.
EXTERNAL COMPONENTS LIST
To set the SLIC into operation the following para-
meters have to be defined:
Once, the above parameters are defined, it is
possible to calculate all the external components
using the following table.
The typical values has been obtained supposing:
- Rfeed = 400
- Zs = 600
- Zl = 600
- Rp = 40
- Zlttx = 216 + 120nF @ 12KHz
- Re[Zlttx] = 216
- Im[Zlttx] = -110 @12KHz
- V
= 55mA.
- The DC feeding resistance ”Rfeed” defined as
- The AC SLIC impedance at line terminals ”Zs” to
- The equivalent AC impedance of the line ”Zl”
- The value of the two protection resistors Rp in
- The line impedance at the TTX freq. Zlttx.
- The reverse polarity transition time defined as
the resistance of
system (most common Rfeed values are:
400, 800, 1000 ohm).
which the return loss measurements is referred.
It can be real (typ. 600ohm) or complex.
used for evaluation
performance (2/4wire conversion). It
ally a complex impedance.
series with the line termination.
” V
TR
/ T = 4250[V/s]
TR
/ T”.
RING-TRIP
DISABLE
OFF/HK
OFF/HK
OFF/HK
OFF/HK
OFF/HK
ODET
–
the
of the trans-hybrid loss
OUTPUTS
traditional feeding
DISABLE
DISABLE
GDKEY
GDKEY
GDKEY
GDKEY
GDKEY
OGK
–
L3037
is usu-
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