SGS Thomson Microelectronics L3234, L3235 Datasheet

HIGHLY INTEGRATEDSLIC KIT TARGETED TO PABX

AND KEY SYSTEM APPLICATIONS

HIGHLY INTEGRATED SUBSCRIBER LINE
INTERFACE KIT FOR PABX AND KEY SYS­TEM APPLICATIONS

IMPLEMENTS ALL KEY ELEMENTS OF THE
BORSCHTFUNCTION

INTEGRATEDZERO CROSSING BALANCED
RINGING INJECTION ELIMINATES EXTER­NAL RELAY AND CENTRALISED RINGING
GENERATOR

ZERO NOISE INJECTED ON ADJACENT
LINES DURING RINGING SEQUENCE

LOW POWER IN STANDBY AND ACTIVE
MODES

BATTERY FEED WITH PROGRAMMABLE
LIMITINGCURRENT

PARALLELLATCHED DIGITAL INTERFACE
SIGNALLING FUNCTIONS (OFF HOOK,

GND-KEY)
LOW NUMBER OF EXTERNAL COMPO-

NENTS
INTEGRATEDTHERMAL PROTECTION
INTEGRATED OVER CURRENT PROTEC-

TION
0°CTO70°C: L3234/L3235

-40°CTO85°C: L3234T/L3235T

L3234
L3235

HEPTAWATT

ORDERING NUMBER: L3234

PLCC28

ORDERING NUMBER: L3235

injectorfabricatedin Bipolarin 140V Technology.
Its function is to amplify and inject in balanced

mode with zero crossing the ringing signal. The

DESCRIPTION

The L3234/L3235is a highly integrated SLIC KIT
targeted to PABX and key systemapplications

The kit integrates the majority of functions re­quired to interface a telephone line. The
L3234/L3235implementsthe main featuresof the
broths function:

- Battery Feed (BalancedMode)

- Ringing Injection

- Signalling Detection

- Hybrid Function
The Kit comprises 2 devices, the L3234 ringing

Janauary 1995

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

device requires an external positive supply of
100V and a low level sinusoid of approx.
950mVrms. The L3235 Line Feeder is integrated
in 60V Bipolar Technology. The L3235 provides
batteryfeed tothe line with programmablecurrent
limitation. The two to four wire voice frequency
signal conversion is implemented by the L3235
and line terminating and balance impedancesare
externally programmable. The L3234/L3235kit is
designed for low power dissipation. In a short
loop conditionthe extrapower is dissipated on an
external transistor. The Kit is controlled by five
wire parallel bus and interfaces easily to all first
and programmable second generation COMBOS.
(seefigg. 1 and 2)

1/26

L3234 - L3235

Figure1: Typical ApplicationCircuit with SecondGeneration COMBO for Complete Subscriber Circuit

(Protection-SLIC-COMBO)

2/26

L3234 - L3235

Figure2: Typical ApplicationCircuit with First GenerationCOMBO for Complete Subscriber Circuit

(Protection-SLIC-COMBO)

3/26

L3234 - L3235

L3234

Solid State Ringing Injector

DESCRIPTION

The L3234 is a monolithic integratedcircuit which
is part of a kit of solid state devices for the sub­scriber line interface. The L3234 sends a ringing
signal into a two wires analog telephone line in
balanced mode. The AC ringing signal amplitude
is up to 60Vrms, and for that purpose a positive
supply voltage of +100V shall be available on the
subscribercard.

The L3234 receives a low amplitude ringing sig­nal (950mVrms) and provide the voltage/current
amplification (60Vrms/70mA) when the enable in­put is active (CS > 2V). In disable mode (CS <

0.8V) the power consumption of the chip is very
low (<14mW).

The circuit is designed with a highvoltage bipolar
technology(V

>140V / V

CEO

CBO

>250V).

HEPTAWATT

The packageis a moulded plastic power package
(Heptawatt)suitable also for surface mounting.

BLOCK DIAGRAM

4/26

PIN CONNECTION (Top view)

L3234 - L3235

7
6
5
4
3
2
1

D94TL131

OUT2
V100
OUT1
GND
VCC
CS
VA

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V100 Positive Power SupplyVoltage +120 V

V

V

CS Logical Ring DriveInput V

T

T

5V Power Supply Voltage 5.5 V

CC

Low Voltage Ringing Signal (with V100 = 120Vdc) 1.4 Vrms

A

CC

Max. Junction Temperature 150

j

Storage Temperature -55 to +150

stg

OPERATINGRANGE

Symbol Parameter Value Unit

V100 High Power Supply Voltage 95 to 105 V

V

V

T

T

Low Power Supply Voltage 5 ±5% V

CC

Low Voltage Ringing Signal

A

Operating Temperature for L3234

op

Max. Junction Operating Temperature (due to thermal protection) 130 °C

jop

L3234T

600 to 950

within 10Hz -100Hz

0to70

-40 to 85

o

C

o

C

Vrms

°C
°C

Note: Operating ranges definethose limits between which the functionality ofthe device is guaranteed.

THERMAL DATA

Symbol Description Value Unit

R

th j-case

R

th j-amb

Thermal ResistanceJunction-case
Thermal ResistanceJunction-ambient

Max.
Max.

4

50

PIN DESCRIPTION

Pin Name Description

1 VA Low Voltage Ringing Signal Input
2 CS Logical Ring Drive Input
3V

CC

4 GND Common Analog-Digital Ground
5 OUT1 Ringing Signal Output
6 V100 +100V High Power Supply

+5V Low Power Supply

o

C/W

o

C/W

5/26

L3234 - L3235

OPERATIONDESCRIPTION

The Fig. 3 show the simplifiedcircuit configuration

Figure3: L3234/L3235Circuit Configuration

CO1

CO2

RO1

RO2

TIP

LINE TERMINALS

RING

LINE FEEDER

A

B

L3235

of the L3234 Solid State Ringing injector when
used with the L3235 Line Feeder.

+5VGND+100V

C100 CVCC

VCCGNDV100

643

CS

5

RINGING INJECTOR

7

L3234

2

CA

1

VA

VA

D94TL132

OUT1

OUT2

CS

GND

-VBAT

EXTERNALCOMPONENTSLIST

In the followingtable are shown the recommendedexternalcomponentsvalues for L3234.

Ref. Value Involved Parameter or Function

R01, R02 82Ω Ringing Feeding SeriesResistors
C01, C02 10µF - 160V Ringing Feeding Decoupling Capacitors

CA 4.7µF - 10V Low LevelRinging Signal De coupling Capacitor
C100 100nF - 100V Positive Battery Filter
CV

CC

When the ringing function is selected by the sub­scriber card, a low level signal is continuously ap­plied to pin 1 througha de couplingcapacitor.Then
thelogicalringdrivesignalCS providedby L3235is
appliedto pin2 witha cadencedmode.

The ringing cycles are synchronised by the L3234
in such a way that the ringing starts and stops al­wayswhenthe analoginputsignalcrosses zero.

When the ringing injection is enabled (CS = ”1”),
an AC ringing signal is injected in a balanced

6/26

100nF +5V Supply Filter

modeinto thetelephone line.
When the ringing injection is disabled (CS = ”0”),

the output voltage on OUT2 raises to the high
power supply, whereas on OUT1, it falls down to
ground.

The L3234 has a low output impedance when
sending the signal, and high output impedance
when the ringing signal is disabled

In fig. 4 the dynamic features of L3234 are
shown.

Figure4: Dynamic Features of L3234

L3234 - L3235

DATATRANSMISSION INTERFERENCE TEST

The L3234 meet the requirementsof the technical
specification ST/PAA/TPA/STP/1063 from the
CNET. The test circuit used is indicated below.

The measured error rate for data transmission is
lower than 10

This test measuresif during the ringing phase the
circuitinduce any noise to the closer lines.

Figure5: Test CircuitData TransmissionInterferenceTest

-6

during the ringing phase.

7/26

L3234 - L3235

ELECTRICAL CHARACTERISTICS (Test conditions:V100 = +100V,VCC= +5V, T

=25°C, unless oth-

amb

erwise specified)
Note: Testing of all parameteris performed at 25°C. Characterisation,as well as the design rule used al-

low correlation of tested performance with actual performances at other temperatures. All pa­rameters listed here are met in the range 0°C to +70°C. For applications requiring operations in
the standard temperature range (0°Cto70°C) use L3234. If operations are required in the ex-
tended temperaturerange (-40°Cto85°C), use theL3234T.

Symbol Parameter Test Condition Min. Typ. Max. Unit Fig

STANDBY MODE: CS = ”0”

IS(V100)

I

S(VCC

V

SOUT1

V

SOUT2

Z

SOUT1

Z

SOUT2

THD Harmonic Distortion During

Consumption VA = 950mVrms; 50Hz 45

)

DC Output Voltage VA = 950mVrms; 50Hz

Output Impedance 70

Z

Matching 15 %

OUT

< 6dBm; f = 1kHz -46 -40 dB 7

V

LINE

Emission

92

70

560

100
800

µA
µA

6V

V

kΩ
kΩ

6

RINGINGPHASE: CS = ”1”
DC OPERATION

IR(V100)

I

)

R(VCC

V

ROUT1

V

ROUT2

V

IH

IIH(CS = 0)

V

IL

IIL(CS = 0)

I

lim

Consumption Z

DC Output Voltage VA = 0V 44

Threshold Voltage on the
Logical Input CS

DC Line Current Limitation VA = 0V 70 150 mA 12

= ∞

LINE

VA = 950mVrms; 50Hz

44

VA = 950mVrms; 50Hz 2.0

2.5

2.2

5
3

56
56

1

0.8
1

mA
mA

V
V

V

µA

V

µA

8

AC OPERATION

V

/VA

OUT1

V

/VA

OUT2

V

OUT1-VOUT1

Ringing Gain Z

Ringing Signal ZLINE = 2.2µF+1kΩ

= 2.2µF+1kΩ

LINE

VA = 0dBm

29.5

29.5

30
30

57 60 Vrms

VA = 950mVrms; 50Hz

THDV

(VA) InputImpedance VA = 950mVrms; 50Hz 40 kΩ 10

Z

IN

Z

OUT

Harmonic Distortion VA = 950mVrms; 50Hz 5 %

LINE

Differential Output Impedance I

< 50mArms 20 Ω 11

LINE

TEST CIRCUITS
Figure6.

8/26

dB
dB

9

9