STLC3080
SUBSCRIBER LINE INTERFACE CIRCUIT
PRELIMINARY DATA
MONOCHIP SLIC SUITABLE FOR PUBLIC
APPLICATIONS
IMPLEMENTES ALL KEY FEATURES OF
THE BORSHT FUNCTION
DUAL CONTROL MODE CONFIGURATION:
SLAVE MODE OR AUTOMATIC ACTIVATION
MODE.
SOFT BATTERY REVERSAL WITH PRO-
GRAMMABLE TRANSITION TIME
ON HOOK TRANSMISSION
LOOP START/GROUND START FEATURE
WITH PROGR. THRESHOLD
LOW POWER DISSIPATION IN ALL OPER-
ATING MODES
AUTOMATIC DUAL BATTERY OPERATION
INTEGRATED RING TRIP DETECTION WITH
AUTOMATIC
AND
SYNCRONISED
RING
DISCONNECTION
METERING PULSE INJECTION
SURFACE MOUNT PACKAGE
THREE RELAY DRIVERS FOR RING AND
TESTING
-40 TO +85
C OPERATING RANGE
DESCRIPTION
The STLC3080 is a SLIC device suitable for a
wide range of applications: public (CO), transmis-
sion (DLC) and private (PABX). The SLIC pro-
vides the standard battery feeding with full pro-
grammability of the DC characteristic. In particular
two external resistors allow to set the limiting cur-
rent value (up to 50mA) and the value of the re-
sistive feeding when not in constant current re-
gion.
This is preliminary information on a new product now in development or undergoing evaluation.
December 1999
BGND
VREG
ILTF
D0
D1
D2
R0
R1
REL1
RS
ZAC
IREF
V
CC
RING
D98TL305B
DET
GDK/AL
CSIN
CAC
AGND CREV CSVR
RELR
REL0
LOGIC
INTERFACE
&
DECODER
SUPERVISION
COMMANDS
LINE STATUS
ILT
LINE
INTERFACE
ILL
TIP
RT1 RT2
CRT
REFERENCE
&
BIAS SWITCHING
DC
PROCESSOR
+
AC+
DC
AC
DC
RLIM
RTH
ZB
TX
V
DD
VBAT
BASE
RDC
AC
PROCESSOR
RGND
RX
ZAC1
CSOUT
TTXIN
PCD
RES
MODE
CKRING
BLOCK DIAGRAM
TQFP44 (10 x 10)
ORDERING NUMBER: STLC3080
1/23
CSOUT
REL1
CSVR
TTXIN
D98TL306A
1
2
3
5
6
4
7
8
9
10
17
11
18 19 20 21 22
44 43 42 41
39
40
38 37 36 35 34
28
27
26
24
23
25
33
32
31
29
30
12 13 14 15 16
CSIN
D0
D1
D2
R0
R1
RES
VDD
VCC
CRT
REL0
RELR
RGND
VBAT
TX
ZB
RS
ZAC
ZAC1
RX
CAC
RDC
ILTF
RT2
RT1
AGND
RTH
RLIM
IREF
CREV
BASE
VREG
BGND
RING
TIP
PCD
MODE
CKRING
DET
GDK/AL
PIN CONNECTION
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
BAT
Battery voltage
-80 + V
CC
to +0.4
-80 + V
REL
to + 0.4
V
V
V
CC
Positive supply voltage
-0.4 to +7
V
V
DD
Control Interface Supply Voltage
-0.4 to +7
V
I
REL
Current into relay drivers
80
mA
A/R/BGND
AGND respect BGND respect RGND
-2 to +2
V
OPERATING RANGE
Symbol
Parameter
Value
Unit
T
opT
Operating temperature range
-40 to +85
C
V
CC
Positive supply voltage
4.75 to 5.25
V
V
DD
Control Interface Supply Voltage
3 to 5.25
V
V
BAT
Battery voltage
if VREL > V
CC
-73 to -15
-78 + V
REL
to -15
V
V
A/R/BGND
AGND respect BGND respect RGND
-0.3 to +0.3
V
PD (70)
Max. power dissipation @ Tamb = 70
C
1.1
W
PD(85)
Max. power dissipation @ Tamb = 85
C
0.9
W
THERMAL DATA
Symbol
Parameter
Value
Unit
R
th j-amb
Thermal resistance Junction to Ambient
Typ.
60
C/W
STLC3080
2/23
PIN DESCRIPTION
Pins
Name
Description
1
CSOUT
Chip-Select for output control bits DET and GDK . Active Low. (*)
2
CSIN
Chip-Select for input control bits latches D0 D1 D2 R0 R1 . Active Low. (*)
3
D0
Control Interface input bit 0. (*)
4
D1
Control Interface input bit 1. (*)
5
D2
Control Interface input bit 2. (*)
6
R0
Relay driver 0 command. Active High. (*)
7
R1
Relay driver 1 command. Active High. (*)
8
RES
Reset Input; active low.
9
V
DD
Control interface Power Supply. V
DD
= 3.3V or V
DD
= V
CC
.
10
V
CC
Positive Power Supply (+5V).
11
CRT
Ring-Trip time constant capacitor.
12
REL1
Relay 1 driver output.
13
REL0
Relay 0 driver output.
14
RELR
Ringer Relay driver output.
15
RGND
Relay drivers ground.
16
V
BAT
Negative Battery Supply.
17
TX
4 wires output stage (Transmitting Port).
18
ZB
Cancelling input of Balance Network for 2 to 4 wires conversion.
19
RS
Protection resistors image. The image resistor is connected between this node and ZAC.
20
ZAC
AC impedance synthesis.
21
ZAC1
RX buffer output/ AC impedance is connected between this node and ZAC.
22
RX
4 wires input stage (Receiving Port). A 100K external resistor must be connected to AGND to
bias the input stage.
23
TTXIN
Metering Signal Input (AC) and Line Voltage Drop Programming (DC). If not used must be connectd
to AGND.
24
CAC
AC feedback input/ AC-DC split capacitor is connected between this node and ILTF.
25
RDC
DC current feedback input. The RDC resistor is connected between this node and ILTF.
26
ILTF
Transversal Line Current Image.
27
RT2
Input pin to sense ringing current , for Ring-Trip detection.
28
RT1
Input pin to sense ringing current , for Ring-Trip detection.
29
AGND
Analog ground.
30
RTH
Off-Hook threshold programming pin.
31
RLIM
Limiting current programming pin.
32
IREF
Voltage reference output to generate internal reference current.
33
CREV
Reverse polarity transition time programming.
34
CSVR
Battery supply filter capacitor.
35
BASE
Driver of the external transistor. Connected to the base.
36
VREG
Regulated voltage. Provides the negative supply to the power line drivers. It is connected to the
emitter of the external transistor.
37
BGND
Battery ground.
38
RING
B wire termination output. IB is the current sunk into this pin.
39
TIP
A wire termination output. IA is the current sourced from this pin.
40
PCD
Power Cross Detection Input
41
MODE
Interface Control Mode selection.
42
CKRING
Clock at ringing frequency for relay synch and time reference for Automatic activation
43
DET
Off-hook and Ring-Trip detection bit. Tri-State Output/Active Low.
44
GDK/ AL
Ground-Key/Alarm detection bit. Tri-State Output. Active Low.
* Input pins provided with 15
A sink to AGND pull-down.
STLC3080
3/23
A parallel interface allow to control the operation
of STLC3080 through a control bus:
- D0 D1 D2 latched input bits defining the Slic
operation mode
- R0 R1 latched input bits (active High) drive the
test relays.
- DET and GDK/AL , tri-state outputs, signal the
status of the loop: On/Off-Hook and Ground-Key.
Pin GDK/AL goes low also when the device
thermal protection is activated or a line fault (Tip to
Ring, Tip and/or Ring to Ground or VBAT) is
detected(flowing current
7.5mA).
-CSIN: chip select for input bits, active Low,
strobes the data present on the control bus into
the internal latch.
- CSOUT: chip select for output bits ; active Low ,
when high DET and GDK/AL goes tri-state.
D0 D1 D2 R0 R1 CSIN and CSOUT inputs are
provided with a 15
A pull-down current to prevent
uncontrolled conditions in case the control bus
goes floating.
According to the above table, 8 operating modes
can be set:
1) Power-Down.
2) Stand-By.
3) Active N.P.
4) Active R.P.
5) Ringing (with SLIC Active N.P.).
6) Ringing (with SLIC Active R.P.).
7) Ground start.
8) High Impedance Feeding.
Power-Down
It's an idle state characterised by a very low
power consumption; any functionality is disabled;
only
relays Rel0 and Rel1 can be
driven by
proper setting of bits R0 and R1.
It can be set during out of service periods just to
reduce the power consumption.
It is worth noticing that two other conditions can
set the Slic in idle state but with some differences
as reported in the table:
Idle State
Rel0/1 Drive
DET
GDK/AL
Power Down
Enable
Disable
Disable
Reset
Disable
Disable
Disable
Thermal
Alarm
Enable
Low
Low
Stand-By.
Mode selected in On-Hook condition when high
immunity to common mode currents is needed for
the DET bit.
To reduce the current consumption, AC feedback
loop is disabled and only DET and GDK/AL de-
tectors are active.
DC current is limited at 16mA (not programma-
ble); feeding characteristic shown in fig. a.
The voltage drop in on-hook condition is 7.8V.
Active
Mode selected to allow voice signal transmission.
When in ACTIVE mode the voltage drop in on-
hook condition is 7.8V in order to allow proper on-
hook transmission (Fig. b).
CONTROL INTERFACE
Slave mode (MODE=Low).
INPUTS
OPERATING MODE
OUTPUTS
R0
R1
D0
D1
D2
DET
(Active Low)
GDK/AL
(Active Low)
X
X
X
X
X
X
X
X
0/1
X
X
X
X
X
X
X
X
X
X
0/1
0
0
0
0
1
1
1
1
X
X
0
0
1
1
0
0
1
1
X
X
0
1
0
1
0
1
0
1
X
X
Power down
Stand-by
Active N.P.
Active R.P.
Ringing (with SLIC Active N.P.)
Ringing (with SLIC Active R.P.)
Ground start
High Impedance Feeding
Rel 0 (on = 1, off = 0)
Rel 1 (on = 1, off = 0)
disable
off/hk
off/hk
off/hk
ring/trip
ring/trip
off/hk
off/hk
def by D0-D2
def by D0-D2
disable
gnd-key
gnd-key
gnd-key
disable
disable
gnd-key
disable
def by D0-D2
def by D0-D2
16mA
R
FEED
= 2R
P
D98TL307
V
BAT
-7.8V
I
V
Figure a: STLC3080 DC Characteristic in
Stand-By Mode.
STLC3080
4/23
Resistive Region is programmable by means of
external resistor R
DC
, limiting current can be se-
lected by R
LIM
resistor.
Concerning AC characteristic the STLC3080 allows
to set 2W termination impedance by means of one
external scaled impedance that may be complex.
Two to four wire conversion is provided by an exter-
nal network. Such network can be avoided in case
of application with COMBOII, in this case the two to
four wire conversion is implemented inside the
COMBOII by means of the programmable Hybal fil-
ter.
When in ACTIVE mode it is also possible to per-
form battery reversal in soft mode (with program-
mable transition time) without affecting the AC sig-
nal transmission.
Ringing
When Ringing mode is selected the STLC3080
activates the ring relay injecting the ringing signal
on the line. As the ring trip is detected the logic in-
dicator DET is set low and the ringing is automat-
ically disconnected without waiting for the card
controller command (auto ring trip).
DET remains latched Low untill the operative
mode is modified.
If required , the ringing relay drive signal RELR
can be synchronised to a clock applied to
CKRING input.
This clock is derived from the ringing signal with
proper time delay, according to the activation/de-
activation time of the relay.
RELR is activated on the low level of CKRING
clock. The duty cycle of CKRING can be modified
in order to activate the RELR when required:
CKRING low must last 1
s minimum.
If the synchronisation is not required, CKRING in-
put must be steadily kept Low.
All the STLC3080 relay drivers are open drain
with the source connected to the RGND pin. Each
relay drivers integrates a protection structure that
allows to avoid external kick - back diodes, using
both 5V or 12V relays.
The ring trip circuit and its behaviour is described
in Appendix D.
Ground Start.
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 Imped-
ance (100k
) while the RING one is active and
fixed at Vbat +4.8V. In the case of connection of
RING termination to GND the sinked current is
limited to 30mA. When RING is connected to
GND both Off-Hook and Ground-Key detectors
become active. Power dissipation in this mode
with a -48V battery voltage is 100mW
High Impedance Feeding.
As Stand-By, this mode is set in On-Hook condi-
tion, with further reduced power consumption.
Higher power efficiency turns back a lower immu-
nity of the Off-Hook detector to line common
mode currents.
The DC feeding shows a constant current charac-
teristic (I
lim
= 17mA) followed by a resistive range
with an equivalent series resistance R
FEED
=
1600
+ 2Rp.
Thermal protection circuit is still active, preventing
the junction temperature, in case of fault condi-
tion, to exceed 150
C
In High Impedance Feeding most of the circuit is
switched off, only the circuit, dedicated to Off-
Hook detection, is powered. This allows to reduce
the total power consumption in On-hook to 30mW
(typical).
The Off-Hook detection threshold is not program-
mable but defined at a fixed IDET
HI
= 8mA(max.)
I
LIM
[20
50mA]
R
FEED
=
R
DC
5
+2R
P
R
FEED
= 2R
P
V
BAT
V
BAT
-7.8V
I
V
Figure b. STLC3080 DC Characteristic in
Active Mode.
17mA
R
FEED
= 1600
+2R
P
D98TL373
V
BAT
-0.8V
I
V
Figure c. STLC3080 DC Characteristic in High
Impedance Feeding
STLC3080
5/23
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