STLC3080 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC3080' PDF : 23 Pages View PDF
STLC3080
When a fault is detected the line current is limited
in order to avoid any damage on the device itself
and also on the external transistor.
MISCELLANEOUS
- Thermal overload: the integrated thermal pro-
tection is activated when Tj reaches 150°C typ.;
the Slic is forced in Power-down mode, DET
and AL are set Low. The RELR relay driver is
turned off while it is still possible to control
REL0 and REL1 through R0 and R1 inputs.
- One low cost external transistor allows to re-
duce the power dissipated in the SLIC itself al-
lowing the use of extreme small size package
(TQFP44). The external transistor size/package
can be selected depending on the max. power
requested by the particular application.
- The SLIC supports loop start lines and gives
the possibility to set loop current indicator
threshold by means of one external resistor.
EXTERNAL COMPONENTS LIST
To set the SLIC into operation the following pa-
rameters have to be defined:
- The DC feeding resistance ”Rfeed” defined as
the resistance of the traditional feeding sys-
tem (most common Rfeed values are: 400,
800, 1000 ohm).
- The AC SLIC impedance at line terminals ”Zs”
to which the return loss measurements is re-
ferred. It can be real (typ. 600 ohm) or com-
plex.
- The equivalent AC impedance of the line ”Zl”
used for evaluation of the trans-hybrid loss
performance (2/4wire conversion). It can be a
complex impedance.
- The value of the two protection resistors Rp in
series with the line termination.
- The reverse polarity transition time defined as
”∆VTR/∆T”.
- The constant current limit value ”Ilim”.
- Rth: sets the OFF/Hook DETection threshold
Once, the above parameters are defined, it is
possible to calculate all the external components
using the following table.
EXTERNAL COMPONENTS
Name
CVCC
CVB
RREF (*)
CSVR
Function
Positive Supply Filter
Battery Supply Filter
Internal current reference
programming resistor
Battery ripple rejection capacitance
CRT
Ring Trip capacitance
Formula
IREF=
1.16
RREF
CSVR =
2π
⋅
fp
1
⋅ 1.3MΩ
see Appendix D
RDC
CAC
RS
ZAC
ZA
ZB
CCOMP
RR
RS1
RS2
RT
QEXT
RPT1
RPR1
DC sinthesized resistance
programming resistor
AC/DC splitter capacitance
Protection resistor image
2 wire AC impedance
SLIC impedance balancing network
Line impedance balancing network
AC feedback compensation
capacitance
Feeding resistance for Ring Injection
Sensing resistor for Ring Trip
Sensing resistor for Ring Trip
Feeding resistance for Ring Injection
External transistor
Line series resistor
Line series resistor
RDC = 5[Rfeed -2Rp]
RDC ≥ 1kΩ
CAC =
2π
⋅
1
fsp
⋅
RDC
RS = 25 ⋅ 2Rp
ZAC = 25[Zs - 2Rp]
ZA = 25 ⋅ Zs
ZB = 25 ⋅ Zl
CCOMP
=
2π
⋅
2
fo[100
⋅
Rp]
≥400Ω
1000 ⋅ RR
1000 ⋅ RR
≥0Ω
(1)
≥20Ω
≥20Ω
Typical Value
100nF ±20%
100nF ±20% 100V
30.1kΩ ± 1%
100nF ±10% 100V
@ fp = 1.22Hz
470nF ±20% 6V
@ 25Hz
1.5kΩ ±1%
10µF ±20% 15V
@ fsp = 10Hz
2.5kΩ ±1%
12.5kΩ ±1%
15kΩ ±1%
15kΩ ±1%
220pF ±20%
@ fo = 250kHz
600Ω 2W
600kΩ ±1%
600kΩ ±1%
0Ω
BD140
20Ω 1/4W ±1%
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