SGS Thomson Microelectronics L3037QN, L3037FN Datasheet

SUBSCRIBER LINE INTERFACE CIRCUIT

MONOCHIP SILICON SLIC SUITABLE FOR
PUBLIC/PRIVATEAPPLICATIONS

IMPLEMENTS ALL KEY FEATURES OF THE
BORSCHTFUNCTION

SOFT BATTERY REVERSAL WITH PRO­GRAMMABLETRANSITION TIME(3 to 100ms)

METERING PULSE INJECTION AND FILTER­ING WITH MINIMAL COMPONENTS COUNT
(NO TRIMMING REQUIRED).

PROTECTION RESISTOR MISMATCH COM­PENSATION

ON HOOKTRANSMISSION
LOOP START/GROUNDSTARTFEATURE
IND TEMP. RANGE:

-40°C TO +85°C
LOW POWER DISSIPATION IN ALL OPER-

ATING MODES
INTEGRATED ZERO CROSSING RELAY

DRIVER
INTEGRATED (NOISE-LESS) RING TRIP DE-

TECTION
VERY LOW NO. of STD TOLERANCE EX-

TERNAL COMPONENTS
SELECT PART FOR U.S. APPLICATIONS

(63dB TYP. LONG.BALANCE)
SURFACE MOUNT PACKAGE (PLCC44 or

BLOCK DIAGRAM

L3037

PLCC44 PQFP44(10 x 10)

ORDERING NUMBERS:

L3037FN L3037QN

PQFP44)
INTEGRATEDTHERMAL PROTECTION
PIN TO PIN COMPATIBLEWITH L3035/36

DESCRIPTION

The L3037 subscriber line interfacecircuit is a bi­polar device in 70V technologydeveloped for cen­traloffice/ loop carrierandprivateapplications.

The L3037 is pin to pin and function compatible
with L3035/36. One particular pin (reserved in
L3035/36) is now used for reverse polarity transi­tion time programming.The line polarity transition
is not affecting the AC signal transmission that
can continue also during the line voltage transi­tion.L3037 is available in two different package
options:PLCC44 and PQFP44 (10 x 10mm).

December 1997

This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

1/22

L3037

L3037 PIN FUNCTIONALITY(PLCC44)

No. Name Function

1
2
3
4
5
6
7
8
9

10 to14

15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

32 to 36

37
38
39
40
41
42
43
44

V

CC

I

LTF

RDC

CF
BASE
BGND
VREG

STIP

TIP

VB

RING

SRING

CRT

ODET

RGIN

OGK

GST

D1

D0

LIM
V

SS

REL
CREV
GREL

CAC

RS
ZB
VB

Tx

Rx

Z

AC

TTXIN

RTTX
ACFD
AGND

I

REF

Supply input (+5V)
Analog output (current source)
Analog input (current input)
Analog input (voltage input)
Analog output (voltage source)
Ground input (0V)
Supply input (VREG)
Analog input (voltage input)
Analog output (voltage output)
Supply input (-V

BAT

)
Analog output (voltage output)
Analog input (voltage input)
Analog input/output (voltage input / current output)
Digital output (voltage output with internalpull up)
Analog input (current input)
Digital output (voltage output with internalpull up)
Digital input (voltage input, internal pull down)
Digital input (voltage input)
Digital input (voltage input)
Digital input (voltage input 3 levels: 0, +5, open)
Supply input (-5V)
Digital output (voltage output open drain)
Analog input/output (voltage input/current output)
Ground input (0V)
Analog input (current input)
Analog input/output (current output/voltage input)
Analog input (voltage input)
Supply input (-V

BAT

)
Analog output (voltage output)
Analog input (voltage input)
Analog output (voltage output)
Analog input (voltage input)
Analog output (voltage output)
Analog input (voltage input)
Ground input (0V)
Analog input/output (voltage output/current input)

L3037 FUNCTIONAL DIAGRAM

OGK

ODET

D0

AC

LINE

STATUS

1

TTXIN

2/22

D1

GST

LIM

RX

ZAC

ZB

TX

D94TL136

LOGIC

INTERFACE

&

DECODER

1

-

+

1

2.32

PROCESSOR

ACFD RS CAC RTTX IREF VCC VSS AGND CREV VB CF BASE

CRTRELGREL RGIN

ICRT

ILT

ICRTVREF

SUPERVISION

COMMANDS

REFERENCE

SWITCHING

&

BIAS

0 CROSS
DETECT.

BIAS

ILT

ILL

AC+DC

(IA+IB)/200

(IA-IB)/200

LINE

INTERFACE

PROCESSOR

IREV

AC

DC

(IA+IB)/200

DC

1

-1

REGULATOR

IA

IB

SUPPLY

STIP

TIP

RING

SRING

BGND
VREG
ILTF

RDC

L3037

PIN CONNECTION

(Topview)

PLCC44

VREG

STIP

TIP
N.C.
N.C.
N.C.

RING

SRING

N.C.

CRT

CC

ILTF

IREF

AGND

N.C.

ACFD

REL

CREV

RTTX

GREL

33
32
31
30
29
28
27
26
25
24
23

D94TL129

BGND

BASECFRDC

44 43 42 41 3940 38 37 36 35 34

1

VB

2
3
4
5
6
7
8
9

10

12 13 14 15 16

ODET

RGIN

PQFP44

OGK

V

171118 19 20 21 22

D0

D1

GST

LIM

SS

V

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

V

agnd

V
V

V

I

T

bgnd

REL

dig

T

Battery Voltage -64 to VSS+0.5 V

bat

Positive Supply Voltage (0 to 1ms)

CC

(continuous)

Negative Supply Voltage (0 to 1ms)

SS

(continuous)

-

Agnd Respect Bgnd (continuous) -2 to +2 V

-0.4 to +7

-0.4 to +5.5

-7 to +0.4

-5.5 to +0.4

Ring Relay Supply Voltage 14 V
Digital I/O D0, D1, GST, LIM, ODET, OGK -0.4 to +5.5 V

dig

Digital I/O D0, D1, GST, LIM, ODET, OGK -3 to +3 mA
Maximum Junction Temperature +150 °C

j

Storage Temperature -55 to +150 °C

stg

Hu Humidity 5 to 95 %

Note: In caseof poweron, power failureor hotinsertion withVDD,VSSpresent andV

with Vbat> V
not controlled. This effect can be prevented ensuring that Vbat is always present before V
(e.g. BAT49X or equivalent) between Vbat and V

+0.5V. In this case the power consumption of the device increases and the logic output state including relay driver are

SS

. One diode can be shared between all the SLICs of the same line card.

SS

floatingthe AbsoluteMaximum Ratings can be exceeded

bat

and VSSor connecting one shottky diode

DD

OPERATINGRANGE

TTXIN
ZAC
RX
TX
N.C.
VB
N.C.
N.C.
ZB
RS
CAC

V
V

V
V

Symbol Parameter Value Unit

V

T

agnd

V

V

V
V

V

bgnd

REL

Operating Temperature Range -40 to +85 °C

op

-

Difference between Agnd and Bgnd -2 to +2 V
Positive Supply voltage +4.5 to +5.5 V

CC

Negative Supply Voltage -5.5 to -4.5 V

SS

Battery Voltage -62 to -17 V

bat

Ring Relay Supply Voltage 4 to 13 V

THERMAL DATA

Symbol Parameter PLCC44 PQFP44 Unit

R

th j-amb

Thermal Resistance Junction-ambient Max. 45 75

C/W

°

3/22

L3037

PIN DESCRIPTION

Unless otherwise specified all thediagrams in this datasheet refers to the PLCC44 Pin Connection.

PQFP44

No.

39 1 V
40 2 I
41 3 RDC DC feedback input (the RDC resistor is connected from this node to I
42 4 CF Battery voltage ripple rejection (C

PLCC44

No.

Pin Description

Positive Power Supply (+5V)

CC

Transversal Line Current Image ((IA+IB) / 200)

LTF

capacitor is connectedfrom this node to BGND).

SVR

LTF

)

43 5 BASE Driver for external transistor base
44 6 BGND Battery ground

2 7 VREG Regulated Voltage. Provides negative power supply for the power amplifier.

(connected to emitter of theexternal transistor.)

3 8 STIP Input of A power amplifier (when no compensation of ext. ptc resistor mismatchis

requested it must be shorted to the TIP lead).

4 9 TIP A line termination output (I

1, 28 10 to 14

32 to 36

VB Battery Supply

PLCC44: All pins are internally connected together.

is thecurrent sourcedfrom this pin).

A

PQFP44: It is mandatory to short pin 1 and pin 28 as closed as possible to thedevice.

8 15 RING B line termination output (I

is thecurrent sunkinto this pin).

B

9 16 SRING Input of B power amplifier (when no compensation of ext. ptc resistor mismatchis

requested it must be shorted to the RING lead).
11 17 CRT Ring trip and ground key capacitor
12 18 ODET ON/OFF hook and RING TRIP output (when disable is internally pulled up)
13 19 RGIN Ring input signal. (when openis internally pulled to GND)
14 20 OGK Ground key output (when disable is internally pulled up)
15 21 GST A open command (whenopen is internally pulled down)
16 22 D1 Bit 1
17 23 D0 Bit 0
18 24 LIM Current Limitation Program. (when open is internally forced to 44mA current limitation)
19 25 V

Negative Power Supply (-5V)

SS

20 26 REL Ring relay driver output
21 27 CREV Reverse polarity transition time control. One proper capacitor connected between this

pin and AGND is setting the reverse polarity transition time. If reverse polarity feature

is not used must be open or connected to AGND through a filter capacitor.
22 28 GREL Ground reference for ring relay driver
23 29 C
24 30 R
25 31 Z

AC feedback input (ACDC split capacitor is connected from this node to ILTF)

AC

Protection resistors image(the image resistor is connected from this node to ACFD)

S

Balance network for 2 to 4 wire conversion (the balance impedance ZBisconnecetd

B

from this node to AGND. The Z

impedance is connected from this node to ZAC)

A

30 37 Tx 4 wire outputport (Tx output)
31 38 Rx 4 wire receiving port. (Rx input)
32 39 Z
33 40 TTXIN Metering input port/V

Rx buffer output (the AC impedance is connected from thisnode to ACFD)

AC

programming. If notused should be connected to AGND.

drop

34 41 RTTX Metering cancellationnetwork. If not used should be left open.
35 42 ACFD AC impedance synthesis
37 43 AGND DC andAC signalground
38 44 I

2,5 to 7,

10,26,

–

N.C. Not connected

Voltage Reference Output

REF

27, 29,36

4/22

L3037

DESCRIPTION

(continued)

One special selection with high longitudinal balan­ce performancesallows to meet the UnitedStates
BELLCORE requirements for central office/loop
carrier and privateapplications.

The SLIC integrates loop start, ground start,
ground key on/off-hook,automatic ring-trip as well
as zero crossing ring relaydriver.

Two to four wire conversionis implemented by the
SLIC for application with first generation COMBO.
In caseof applicationwith secondgeneration (pro­grammable) COMBO this function can be imple­mentedoutsidesavingexternalcomponents.

The L3037 offers programmablecurrent limitation
(3 ranges), on hook transmission and low power
in all operating modes, power management is
controlled by a simpleexternallow costtransistor.

Metering pulses are injectedon the line via a sum­mingnodethroughTTXIN pin.
Metering pulse filtering is performed by means of a
simple RC networkwith standardtolerancecompo­nents. In case TTX function is not used this pin
must be connected to AGND. It is also possible to
usethis pin to modifythe DC voltagedropbetween
TIP/RING terminalsand batteryvoltagefor appica­tions where it is important to optimize the battery
voltagesupplyversusthesignalswing.
Effect of protection resistors mismatch are com­pensated by a feedbackloop on thefinal stageal­lowing good long balance performances also with
large toleranceprotection resistors(ex: PTC).

This function allow the L3037 to be fully conform
to BELLCORE power cross and surge test and
meet also the Longitudinal Balance Specification
without using matched PTC resistors.

An integrated thermal protection circuit forces the
L3037 in POWER DOWN (PD) mode when the
junction temperature exceeds 150°C Typ.

The L3037 is specified over -40°C to +85°Cam-
bient temperaturerange.
The L3037 package is a surface mount PLCC44
or PQFP44.

FUNCTIONAL DESCRIPTION

L3037 is designed in 70V bipolar technology and
performs the telephone line interface functionsre­quired in both C.O. and PABXenvironments. The
full range of signal transmission, battery feed,
loop supervisionare performed.

Signal transmission performance is compatible
with European and North American Standards
and with CCITT recommendations.
Ringing, overvoltage and power cross protection
are performed by meansof externalnetworks.

The signal transmission function includes both 2
to 4 wire and 4 to 2 wire conversion.The 2W ter­mination impedance is set by means of an exter­nal impedancewhich may be complex. The 2 to 4

wire conversion is provided by meansof an exter­nal network.

Such a network can be avoided in case of appli­cations with COMBOII, in this case the 2 to4 wire
conversion is implemented inside the COMBOII
by means of the programmableHybal filter.

An additionalinput allows a meteringpulse signal
to be added on the line.

The DC feed resistance is programmable with
one external resistor. Three different values of
current limitation (25, 44, 55mA)can be selected
by softwarethrough the parallel digital interface.

One external transistor reduces the power dissi­pation inside the L3037 in the presence of a short
loop (limiting current region).

An additional supervisory function sets the TIP
lead into high impedance state in order to allow
applicationin ground start configurations.

The different L3037 operating modes are control­led by a 4bit logic interface, two additional detec­tor outputs provide ground key detection and ei­ther hook state or ring tripdetection.

SLIC OPERATINGMODES
Through the L3037 digital interface it is possible

to select 5 differentSLIC operatingmodes:

1) Active Mode (ACT)

2) StandbyMode (SBY)

3) Tip Open Mode (TO)

4) Power Down Mode (PD)

5) Ringing Mode (RNG)
In both ACT and SBY modes it is possible to se-

lect the reversepolarity (see control interface).
Transition from direct to reverse polarity is soft
and the transition time is defined by the external
capacitorCREV.

ACTIVEMODE(ACT)
This operating mode is set by the card controller

whenthe Off-Hookconditionhas beenrecognized.
When this operatingmode is selected the two out-

put buffers (TIP/RING) can sink or source up to
100mA each. In case of Ground key or line termi­nals to GND the outputcurrent is limited to 15mA
fortheTipwireand 30mA for the Ringwire.

As far asthe DC characteristicis concernedthree
differentfeeding conditionsare present:

a) Current limiting region: the DC impedance of
the SLIC is very high( 20Kohm) and therefore the
system works like a current source. Using the
L3037 digital interface it is possible to select the
value of the limiting current:

25mA, 44mA, or 55mA.

When the device is in limiting current region the
negative supply for the output buffer is fixed by

5/22

L3037

the ext. transistor to a proper value higher than
the real negative battery in order to reduce the
power dissipatedby the L3037 itself.

b) Resistive feed region: the characteristic is
equal to a battery voltage (Vbat) in series with a
resistor (typ 400ohm or 800ohm) whose value is
set by one ext.resistor(see ext. componentslist).

c) Constant voltage region: the characteristic is
equal to the battery voltage - 12V in series with
the ext. protectionresistors (typ 80ohm).

This voltage drop between battery and line termi­nals forIl=0 allowson-hooktransmission.

Fig. 1 shows the DC characteristic in active
mode. Fig. 2 shows the line current versus loop
resistance

Figure 1:

DC Characteristicin activemode

Figure 2: Currentvs. Loop Resistance.

Rfeed = 2 x 200ohm,
Lim. currents: 25, 43, 55mA

1) The lineimpedance (Zline)

2) The SLIC impedance at line terminals (Zs)

3) The balancingnetworkZA+RA connected
betweenpin ZAC and ZB of L3037.

4) The networkZB betweenpin ZB and GND
thatshall copy the line impedance.

When L3037 is used with a second generation
combo(eg TS5070FN)which is able to performthe
two to four wire conversion, the two impedances
ZA and ZB can be removed and the ZB pin con­nectedto GND.The -6dB TX gainof the L3037al­lows the echo signal to remain always within the
COMBOIIHybridbalancefilterdynamicrange.

The injection of high frequency metering pulses is
carried out throughthe SLIC. An unbalanced12 or
16KHzsinusoidal signal with shapingis, when ne­cessary,appliedattheTTXINinputof the SLIC.
A fixedtransfer gain is providedforthe metering si­gnal. To avoid saturation in the 4-wire side a can­cellationis providedin the4-wiretransmissionpath.

Cancellation is obtained via an external RC net­workwithout the needfor trimmed components.

When the TTX function is not used TTXIN input
should be connectedto GND. Since this pin is di­rectly connected to a summing node inside the
SLIC any signal applied to the TTXIN is transfer­red to the line witha fixedtransfer gain.
In special applications, this pin can be used to
modify the voltage drop (constant voltage region
of DC characteristic) simply by applying a proper
DC level on the TTXIN pin, allowing optimization
of the battery voltage versus the maximum nee­ded AC signalswing.

In active mode, with a -48V battery voltage, the
L3037 dissipate 150mW for its own operation (in­cluding the power dissipation from +5/-5 supply),
the dissipation related to the current supplied to
the line should be added in order to get the total
dissipation.

In active mode the AC impedance at the line ter­minals is sinthetized by the external components
ZAC and Rp according to the following formula:

Zs= ZAC/50+ 2*Rp

Depending on the characteristic of the ZAC net­work Zscan be either a pure resistance or a com­plex impedance.This allows L3037 to meet diffe­rent standard as far as return loss is concerned.
The capacitor CCOMP guaranteesstability to the
system.

The two to four wire conversion is achieved by
means of a circuit that can be represented as a
Wheastone bridge, the branchesof which are:

6/22

STAND-BYMODE (SBY)
In this mode thebias current of the L3037 is redu-

cedand only somepartof the circuitarecompletely
active. The transversal current supplied to the line
islimited at 14mA.Common modecurrentrejection
is performed and the total current capability of the
output stages (TIP and RING) is limited to 30mA.
Theopencircuitvoltageis |Vbat|-7V.

Both Off/Hook and Ground key detectorsare acti­ve. Signal transmissionis not operating.

In stand-by mode, with a -48V batter y voltage, the
L3037dissipates90mWtyp.(includingthepowerdis­sipationfroma +5/-5Vsupply).
Stand-bymode isusuallyselectedwhen thetelepho ­ne is in on-hook conditi on.It allow sa properoff-hook
detection, even in the presence of high comm on
modecurrents,or with telephone sets sinking a few
milliamperesof line currentin on-hookconditi on.

CONTROLINTERFACE

L3037

INPUTS

D0 D1 GST LIM ODET OGK

POWER DOWN

0
1
1
1
1
0
0
0

(*) LIM = 0 → I

0
1
1
0
0
1
0
1

lim

0
0
1
0
1
0
1
1

= 25mA; LIM = H. I. (open) → I

X
X

X
X (*)
X (*)

X

X

X

STANDBY D. P.
STANDBY R. P.
ACTIVE D. P.
ACTIVE R. P.
RING
A. OPEN
RESERVED

lim

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 terminationis set in High Impedan­ce (100Kohm) while the RING termination is acti-

OPERATING MODE

= 44mA; LIM = 1 → I

DISABLE

OFF/HK
OFF/HK
OFF/HK
OFF/HK

RING-TRIP

OFF/HK

= 55mA.

lim

Once ring trip is detected the ringing signal is
automatically disconnected at the first zero cros­sing. When the ringing signal phase is not provi­ded at the RGIN pin the ringing signal is discon­nectedimmediately after ring trip detection.

OUTPUTS

–

ve and fixed at Vbat + 4.5V. In the case of con­nection of RING termination to GND the sinked
current is limitedto 30mA. When RING is connec­ted to GND both off-hook and ground-key detec­tors becomeactive.

Power dissipation in thismode witha -48V battery
voltage is 100mW (including the power dissipa­tion from +5/-5V supply).

POWERDOWN MODE (PD)
In thismode, both TIP and RING terminationsare

open and no current is fedinto the line.
The power dissipationis verylow.
This mode is usually selected in emergency con-

dition or when theconnected line is disabled.
This is also the mode into whichthe SLIC is auto-

matically forced, in the case of thermal overload
T

> 150°C typ.

j

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 synchroni­zed with the ringing signal zero crossing.

The TIP and RING termination of the L3037 are
senses the line current which is then integrated
on theCRT capacitor.

TIP pin voltage is fixed at – 2.5V, RING pin volt­age is fixed at V

+ 4.5V,TIP, RING buffer cur-

BAT

rent capability is limited to 100mA.
When off-hook occurs during ringing burst the

voltage on CRT increase above a proper thre-

EXTERNALCOMPONENTS LIST
To set the SLIC into operation the following para-

metershave to be defined:

- The DC feeding resistance ”Rfeed” defined as
the resistance of the traditional feeding
system (most common Rfeed values are:
400, 800, 1000 ohm).

- TheAC SLICimpedanceat lineterminals”Zs” to
whichthereturn lossmeasurementsisreferred.
Itcanbereal(typ.600ohm)or complex.

- The equivalent AC impedance of the line ”Zl”
used for evaluation of the trans-hybrid loss
performance (2/4wire conversion). It is usu­allya compleximpedance.

- The value of the two protectionresistors Rp in
series with the line termination.

- The line impedanceat the TTXfreq. Zlttx.

- The reverse polarity transition time defined as

/∆T”.

”∆V

TR

Once, the above parameters are defined, it is
possible to calculate all the external components
using the followingtable.
The typical values has been obtainedsupposing:

- Rfeed = 400

Ω

- Zs = 600Ω

- Zl =600Ω

-Rp=40Ω

- Zlttx = 216Ω + 120nF @ 12KHz

- Re[Zlttx]= 216Ω

- Im[Zlttx]= -110Ω @12KHz

-∆V

/∆T = 4250[V/s]

TR

shold and ring trip is detected.

DISABLE

GDKEY
GDKEY
GDKEY
GDKEY

DISABLE

GDKEY

–

7/22