SGS Thomson Microelectronics STLC3080 Datasheet



SUBSCRIBER LINE INTERFACE CIRCUIT

MONOCHIP SLIC SUITABLE FOR PUBLIC
APPLICATIONS

IMPLEMENTES ALL KEY FEATURES OF
THE BORSHTFUNCTION

DUALCONTROL MODE CONFIGURATION:
SLAVE MODE OR AUTOMATIC ACTIVATION
MODE.

SOFT BATTERY REVERSAL WITH PRO­GRAMMABLETRANSITION TIME

ON HOOKTRANSMISSION
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
SURFACEMOUNT PACKAGE
THREE RELAY DRIVERS FOR RING AND

TESTING

BLOCK DIAGRAM

STLC3080

PRELIMINARY DATA

TQFP44 (10 x 10)

ORDERING NUMBER: STLC3080

-40 TO +85°COPERATINGRANGE

DESCRIPTION

The STLC3080 is a SLIC device suitable for a
wide range of applications: public (CO), transmis­sion (DLC) and private (PABX). The SLIC pro­vides the standard battery feeding with full pro­grammability of theDC characteristic.In particular
two external resistors allow to set the limiting cur­rent value (up to 50mA) and the value of the re­sistive feeding when not in constant current re­gion.

REL1

RELRREL0

MODE

D0
D1
D2
R0
R1

DET

GDK/AL

CSIN

CSOUT

CKRING

RES

TTXIN

ZB
TX

RX

ZAC1

LOGIC

INTERFACE

&

DECODER

AC

PROCESSOR

RSZAC IREF V

RGND

LINE STATUS

COMMANDS

REFERENCE

BIAS SWITCHING

CAC AGND CREV CSVR

RT1 RT2CRT

SUPERVISION

&

V

CC

DD

PCD

ILT

ILL

AC+

DC

AC

DC

December 1999

This is preliminary information on a new product now indevelopment or undergoing evaluation.

LINE

INTERFACE

+

DC

PROCESSOR

VBAT BASE RDC

TIP
RING

BGND
VREG
ILTF

RLIM
RTH

D98TL305B

1/23

STLC3080

PIN CONNECTION

CSOUT

CSIN

D0
D1
D2
R0

R1
RES
VDD
VCC
CRT

BGND

RING

TIP

PCD

MODE

CKRING

DET

GDK/AL

44 43 42 41 3940 38 37 36 35 34

1
2
3
4
5
6
7
8
9

10

RELR

RGND

VBAT

171118 19 20 21 22

TX

ZB

RS

12 13 14 15 16

REL1

REL0

VREG

ZAC

BASE

ZAC1

CSVR

33
32
31
30
29
28
27
26
25
24
23

RX

CREV
IREF
RLIM
RTH
AGND
RT1
RT2
ILTF
RDC
CAC
TTXIN

D98TL306A

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V
V
I

BAT

CC
DD

REL

Battery voltage -80 + VCCto +0.4

-80 + V

REL

to + 0.4
Positive supply voltage -0.4 to +7 V
Control Interface Supply Voltage -0.4 to +7 V
Current into relay drivers 80 mA

A/R/BGND AGND respect BGND respect RGND -2 to +2 V

OPERATINGRANGE

Symbol Parameter Value Unit

T

opT

V

CC

V

DD

V

BAT

Operating temperature range -40 to +85 °C
Positive supply voltage 4.75 to 5.25 V
Control Interface Supply Voltage 3 to 5.25 V
Battery voltage

if VREL > V

CC

-73 to -15

-78+ V

REL

to -15

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

V
V

V
V

Symbol Parameter Value Unit

R

th j-amb

Thermal resistance Junction to Ambient Typ. 60 °C/W

2/23

STLC3080

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 inputbit 0. (*)
4 D1 Control Interface inputbit 1. (*)
5 D2 Control Interface inputbit 2. (*)
6 R0 Relay driver 0 command. Active High. (*)
7 R1 Relay driver 1 command. Active High. (*)
8 RES Reset Input; active low.
9V

10 V

DD
CC

11 CRT Ring-Triptime 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

17 TX 4 wires outputstage (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 inputstage (Receiving Port). A 100K externalresistor must be connected to AGND to

23 TTXIN Metering SignalInput (AC) andLine Voltage DropProgramming(DC). If notusedmustbe connectd

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 TransversalLine 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 ofthe external transistor. Connected to the base.
36 VREG Regulated voltage. Provides the negative supply to the power line drivers. It is connectedto the

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 InterfaceControl 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 15µA sink toAGND pull-down.

Control interface Power Supply. VDD= 3.3V orVDD=VCC.
Positive Power Supply (+5V).

Negative Battery Supply.

bias the input stage.

toAGND.

emitter of the external transistor.

3/23

STLC3080

CONTROLINTERFACE
Slave mode (MODE=Low).

INPUTS

R0 R1 D0 D1 D2

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

X
X

0
1
0
1
0
1
0
1

OPERATING MODE

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)

A parallel interface allow to control the operation
of STLC3080through a control bus:

- D0 D1 D2 latched input bits definingtheSlic
operationmode

- R0 R1 latched input bits (activeHigh) drive the
testrelays.

- DET and GDK/AL , tri-state outputs, signal the
statusofthe loop:On/Off-Hookand Ground-Key.

PinGDK/AL goeslow also whenthe device
thermal protectionis activatedor a linefault(Tip to
Ring,Tip and/orRingto Groundor VBAT)is
detected(flowing current≥7.5mA).

-CSIN: chipselect for input bits, active Low,
strobesthe data present on the control bus into
theinternal latch.

- CSOUT: chipselect for outputbits; activeLow,
whenhigh DET and GDK/AL goes tri-state.

D0 D1 D2 R0 R1 CSIN and CSOUT inputsare
provided with a 15µA pull-down current to prevent
uncontrolled conditions in case the control bus
goes floating.

According to theabove table, 8 operating modes
can be set:

1) Power-Down.

2) Stand-By.

3) ActiveN.P.

4) ActiveR.P.

5) Ringing(with SLIC Active N.P.).

6) Ringing(with SLIC Active R.P.).

7) Groundstart.

8) HighImpedanceFeeding.

Power-Down

It’s an idle state characterised by a very low
power consumption; any functionalityis disabled;
only relays Rel0 and Rel1 can be driven by
proper settingof bitsR0 and R1.

It can be set during out of service periods just to

OUTPUTS

DET

(Active Low)

disable

off/hk
off/hk

off/hk
ring/trip
ring/trip

off/hk

off/hk

def by D0-D2
def by D0-D2

GDK/AL

(Active Low)

disable
gnd-key
gnd-key
gnd-key

disable

disable
gnd-key

disable

def by D0-D2
def by D0-D2

reducethe power consumption.
It is worth noticing that two other conditions can

set the Slic in idle state but with somedifferences
as reportedin 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 reducethe current consumption, AC feedback
loop is disabled and only DET and GDK/AL de­tectorsare active.

DC current is limited at 16mA (not programma­ble); feedingcharacteristicshown in fig.a.

The voltage drop in on-hook conditionis 7.8V.

Figurea: STLC3080 DC Characteristicin

Stand-ByMode.

I

16mA

R

=2R

D98TL307

FEED

V

BAT

-7.8V

P

V

Active

Mode selected to allow voice signal transmission.
When in ACTIVE mode the voltage drop in on­hook condition is 7.8Vin orderto allowproper on­hook transmission(Fig. b).

4/23

STLC3080

Figure b. STLC3080DC Characteristicin

ActiveMode.

I

I

[20÷50mA]

LIM

R

R

=2R

FEED

FEED

V

P

BAT

=

-7.8V

R

DC

+2R

P

5

V

BAT

V

Resistive Region is programmable by means of
external resistor R
lected by R

LIM

, limiting current can be se-

DC

resistor.

Concerning AC characteristic the STLC3080 allows
to set 2W terminationimpedance by meansof one
external scaled impedance that may be complex.
Two to four wire conversion isprovidedby an exter­nal network.Such network can be avoidedin case
of applicationwith COMBOII,in this casethe two to
four wire conversion is implemented inside the
COMBOII by means of the programmableHybal fil­ter.
When in ACTIVE mode it is also possible to per­form battery reversal in soft mode (with program­mable transition time) without affectingthe AC sig­naltransmission.

Ringing

When Ringing mode is selected the STLC3080
activates the ring relay injectingthe ringing signal
on the line. As the ring trip is detectedthe logic in­dicator DET is set low and the ringing is automat­ically disconnected without waiting for the card
controllercommand (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
CKRINGinput.

This clock is derived from the ringing signal with
proper time delay, according to the activation/de­activationtime of the relay.

RELR is activated on the low level of CKRING
clock. The duty cycleof CKRING can be modified
in order to activate the RELR when required:
CKRINGlow must last 1µs minimum.

If the synchronisation is not required, CKRING in­put must be steadily kept Low.

All the STLC3080 relay drivers are open drain
with the source connectedto theRGND pin. Each
relay drivers integrates a protection structure that
allows to avoid external kick - back diodes,using
both 5Vor 12V relays.

The ring trip circuit and its behaviour is described
in AppendixD.

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 Imped­ance (100kΩ) 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 -48Vbattery voltage is 100mW

High Impedance Feeding.

As Stand-By, this mode is set in On-Hook condi­tion, with furtherreducedpower consumption.

Higher power efficiency turns back a lower immu­nity of the Off-Hook detector to line common
modecurrents.

The DC feeding shows a constant current charac­teristic (I
with an equivalent series resistance R

= 17mA) followed by a resistive range

lim

FEED

1600Ω+ 2Rp.
Thermal protection circuit is still active, preventing
the junction temperature, in case of fault condi­tion, to exceed150°C

In High Impedance Feeding most of the circuit is
switched off, only the circuit, dedicated to Off­Hook detection, is powered. This allows to reduce
the total power consumptionin On-hookto 30mW
(typical).
The Off-Hook detection threshold is not program­mablebut defined at a fixed IDET

= 8mA(max.)

HI

Figurec. STLC3080 DC Characteristicin High

ImpedanceFeeding

I

17mA

D98TL373

R

FEED

= 1600Ω +2R

V

BAT

P

-0.8V

=

V

5/23

STLC3080

CONTROLINTERFACE
Automatic activation mode (MODE=High).

Inputs Operating Mode

R0 R1 D0 D1 D2

X X 0 0 0 1 Power Down disable disable
X X 0 0 1 1 Ringing Ring-Trip disable
X X 0 1 0 1 On-Hook Transmission

X X 0 1 1 1 On-Hook Transmission
X X 1 0 0 1 Active Direct Polarity
X X 1 0 1 1 Active Direct Polarity
X X 1 1 0 1 Active Reverse Polarity Off_Hook
X X 1 1 1 1 Active Direct Polarity

0/1 X X X X 1 R0 = 0/1: Rel0 = off/on (1) (1)

X 0/1 X X X 1 R1 = 0/1: Rel1 = off/on (1) (1)
XXXXX0Power Down; Rel0/1= off disable disable

DET: On/OffHook Signalling; togetherwith GDK/AL it is set Low also in case of Thermal Alarm or Ground-Key.
GDK/AL : Thermal Alarm or Ground-Key Signalling
(1) : DET and GDK/AL signallingfunction is relatedto D0,D1,D2 and it doesn’t depend on R0 and R1 setting.

RES DET GDK/AL

As in Slave mode the control is performed
through a parallel bus, with independent chip se­lects, CSIN and CSOUT, for inputs and outputs.

In Automatic Activation, once Active mode is se­lected the device automatically selects the proper
operating mode (Active,Stand By or H.I. feeding)
depending on the loop status in order to optimise
the power consumption.

In order to guaranteethe proper behaviour of the
internal state machine the ”CKRING” signal must
be always applied,this signalin fact is used to gen­eratethe ”WTIME” delay(see Appendix)necessary
to properlyperformautomaticstatechange.

Power-Down

It’s an idle state characterised by a very low
power consumption; any functionalityis disabled;
only relays Rel0 and Rel1 can be driven by
proper settingof bitsR0 and R1.

It can be set during out of service periods just to
reduce the power consumption.

(Mode = High)

Off-Hook

Reverse Polarity

Off_Hook

Direct Polarity

Off_Hook

(default)

Off_Hook

(default)

Off_Hook

(default)

As a Ring-Trip is detected the logic indicator DET
is set Low and the ringing relay is automatically
switched-off without waiting for the card control­ler command(auto ring-trip).

DET remains latched Low until the operative
modeis modified.
Ringingrelay drive signal RELR must 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 /
deactivationtime 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:
CKRINGlow must last 1µs minimum.
All the relay drivers are open-drain with the
sourceconnectedto RGNDpin.
Each relay driver integrates a protectionstructure
to avoid external kick-back diodes using both 5V
or 12V relays.

The ring trip circuit and its behaviouris described
in AppendixD.

Outputs

Fault
Fault
Fault
Fault
Fault
Fault

It is worth noticing that two other conditions can
set theSlic 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

On-HookTransmission.

Sets the Slic for conversation even thoughthe line
is in On-Hook; it is required for On/Hooktransmis­sion purposes; Active mode cannot supporta con­versationwhenthe lineis in On-Hookasit automat­ically turns in High ImpedanceFeeding.

Active.

Ringing

When Ringing mode is selected the STLC3080
activatesthe ringing relay injecting the ringing sig­nal on the line.

6/23

The relevant feature of this setting is that when
Active Mode (D0D1D2=1XX) is set by the exter­nal control , internally, the device is ableto select
between three operative states according to the
statusof the line:

Fault
Fault
Fault
Fault
Fault
Fault

STLC3080

- High Impedance Feeding :
entered aftera Power-On Resetor 1XX word, this

statusis setduringsteadyOn/Hookcondition;
most of the circuitry is idle and only a low power

Off-Hookdetection circuit iskept alive.
Direct Polarity only is assumed , independentlyof

the selectedone.
To minimisethepowerconsumptiontheOff-Hookde-

tectioncircuithaslowcommonmodecurrentrejection.

-Standby
Notice that in Stand-Bystate theOff-Hook detec-

tor is sensitive only to the transversal component
of the line current with high immunity to common
mode disturbances; this performance implies an
increasing in power consumption: for that reason
Stand-Byis notused as a quiescent state.

- Active state gets operative for conversation af­ter an Off-Hook validity check performed in
Stand-Bystate, set after any Off-Hook detected in
High ImpedanceFeeding.

If the Off-Hook condition is confirmedin StandBy,
Active mode is set ; if not (in case of spuriousde­tection), false activation is prevented, and High
ImpedanceFeeding is resumed.

In order to havethe device falling back in HI-feed­ing mode after the line is back in on-hook condi­tion. It is necessaryto selectas input state the ac­tive direct polarity mode (default).

During Active state On/Off-Hook status will af­fect in real time DET signalling bit.

In order to allow Pulse-Mode Dialling, once Ac­tive state is set, it cannot be changed by fast On­Hook , but it is turned back to High Impedance
Feeding only if an On-Hook condition lasts
longer than 128 x CKRING period.

Automatic activation (and deactivation) is based
on an internal state-machine which is clocked by
a freerunninginternal oscillator.
A detaileddescriptionis reportedin the AppendixA.

DUAL BATTERY CONFIGURATION

STLC3080 is also meant for low power consump­tion systems using Dual Battery solution. It is suf­ficient to connectthe collector of the external tran­sistor, through a diode, to the reduced battery
(see Fig. 2 for single battery solution and Fig. 3
for dual battery solution). The activation of the
batteries is automatic, only depending on the DC
load at the RING and TIP terminals; no controllers
action is required.

PROTECTIONCIRCUIT

- Suggested protection circuit is based on pro­grammable Trisils (like LCP1511/2) as shown
in Fig.2 and Fig. 3, and the surge current is
limited by the resistors RPT2 and RPR2, which
are PTC types , protecting the device against

both lightningand power-cross.

- Additionally, STLC3080 is provided with the
PCD input to directly monitor overvoltages ap­plied to the line wires.

When the current injected into PCD exceeds a
threshold of 320µA (+/- 30%) , DET and GDK/AL
are set Low signalling a fault condition. No
change on theSLIC mode is performed.

Voltage threshold is defined by proper value of
the series resistors (see Fig.1)

This circuit gives the possibility to protect the de­vice against power crosses through a relay in­stead of PTCs; once the fault condition is de­tected the controller drives this relay
disconnectingthe Slic from the line terminals.

METERINGPULSE INJECTION
Figure1.

TIP

RING

VCC

R

PCD

R

Ith

DET

GDK/AL

CSOUT

D98TL385

STLC3080 provides external pins and compo­nents for Metering Pulse injection. TTXIN pin is
the input for the 12kHz or 16kHz Metering Pulse
injection. This pin also provides a DC constant
current source that is injected into the external
RDA resistor (typ. 10kΩ to obtain 2.2Vrms on
200Ω) connected between TTXIN pin and AGND.
The voltage drop across TIP and RING line ampli­fiers and, consequentallythe AC swing available.

When Metering Pulse injection is not used and
voltage drop is not required, TTXIN must be
shorted to AGND and RTTX, RDA and CTTX ex­ternal components must be removed. The TTX
cancellation is obtained through an external
RTTX and CTTX network connected between
TTXIN and CAC pins.

Fault detection

The device provides current sense on TIP and
RING wires that allow to detect longitudinal DC
current (I

). When this ILLcurrent becomes

LL

higher than a threshold (see detectors table in­side electrical characteristics) a fault indication is
provided on DET and GDK pin (both outputs be­come low). The fault indication is active till the
fault cause persists. With this circuit the following
fault condition can be detected.

TIP to VB1
TIP to GND
RINGto VB1
RINGto GND
RINGto TIP to VB1

7/23