SGS Thomson Microelectronics CLP200M Datasheet



CLP200M

ApplicationSpecific Discretes

A.S.D.



OVERVOLTAGE AND OVERCURRENT

PROTECTION FOR TELECOM LINE

MAINAPPLICATIONS

Any telecom equipment submitted to transient
overvoltagesandlightningstrikes suchas:

Analogand ISDNline cards
PABX
MainDistribution Frames
Primaryprotection modules

DESCRIPTION

TheCLP200Mis designedtoprotecttelecommuni­cationequipment.It providesbothatransientover­voltageprotectionand an overcurrentprotection.
It is housedin a PowerSO-10

TM

package.

FEATURES

DUALBIDIRECTIONALPROTECTIONDEVICE.
HIGHPEAKPULSE CURRENT:

Ipp = 100A(10/1000µs SURGE)
MAX.VOLTAGEAT SWITCHING-ON: 290V
MIN.CURRENT AT SWITCHING-OFF : 150mA
FAILURESTATUSOUTPUTPIN

BENEFITS

Both primary and secondaryprotectionlevelsin
onedevice.

Voltageand current controlledsuppression.
SurfaceMountingwithPowerSO-10

TM

package.

Line card cost reduction thanks to the very low
power rating of external components required :
balanced resistors, ring relay, low voltage SLIC
protection.

PowerSO-10

SCHEMATICDIAGRAM

1

TIP

S

TIP

L

TIP

L

TIP

L

TABis connected to GND

TM

NCFS
RING
RING
RING
RING

S

L

L

L

COMPLIESWITH THEFOLLOWINGSTANDARDS :

CCITTK20: 10/ 700µs 4kV

5 / 310µs 100A

BELLCORETR-NWT-000974

10/ 1000µs 1kV
10/ 1000µs 100A

February 1998 Ed : 3

1/21

CLP200M

BLOCKDIAGRAM

TIPL TIPS

Overcurrent

detector

OR

SW3 SW1

FS GND

SW4 SW2

OR

Overcurrent

detector

RINGL RINGS

Overvoltage

detector

Overvoltage

detector

Overvoltage

reference

(+/- 215 V)

Overvoltage

reference

(+/- 215 V)

Pin Symbol Description

1 FS FailureStatus
2 TIPS TIP(SLICside)

3 / 4 / 5 TIPL

TIP(Lineside)

6 / 7 / 8 RINGL RING(Lineside)

2/21

9 RINGS RING(SLICside)

10 NC Not connected

TAB GND Ground



APPLICATION NOTE

1. INTRODUCTION

The aim of this section is to show the behaviorof
ournewtelecomlineprotectiondevice.Thisdevice
includes a primary protection level and is suitable
for main distribution frames and line cards. This
protection concept is explained and, in addition,
the CLP200M performances are analysed when
facing different surgesas described in the CCITT
recommendations.

Fig.1 :

Subscriberline protectiontopology

telecommunication

line

”PRIMARYPROTECTION” ”SECONDARYPROTECTION”

MDF LINECARD

EXCHANGE

SLICCLP200M

CLP200M

2. SGS-THOMSONCLP200M CONCEPT

2.1Evolution of the SLIC protection

Over the years, the silicon protection per­formances have considerably changed .

The first generation of products like SMTHBTxx
and SMTHDTxx offered fixed overvoltage protec­tion against surges on either TIP or RING line in
fourpackages.

The following generation like THBTxx and
THDTxx still offered fixed overvoltageprotection
againstsurgeson both TIP andRINGlines in two
packages.

The next step was the introduction of the
LCP1511D which brought the advantage of full
programmablevoltage.

Today, the CLP200M combines the features of all
the previous generations.In addition to that, it of­fers an overcurrent detection when operating in
speechmode and also a FailureStatusoutputsig­nal.

telecommunication

line

MDF LINECARD

”SECONDARYPROTECTION”

THDTxx or

EXCHANGE

LPC1511D
or LB200B

CLP200M SLIC

Figure 1 is a simplified block diagram of a sub­scriberline protectionthat ismainlyused sofar.

Thisshows two differentthings:

A ”primaryprotection”locatedon theMain Distri­butionFrame(MDF)eliminatescoarselythehigh
energy environmental disturbances (lightning
transientsand AC powermainsdisturbances)

A ”secondaryprotection”locatedon the line card
includesa primaryprotectionlevel(firststage)and
a residualprotection(secondstage)which elimi­natesfinelytheremainingtransientsthathavenot
beentotallysuppressedby thefirststage.

The CLP200M can be used both in MDFs and in
line cards. In that case, any line card may be
swappedfrom one MDFtoanotherone withoutre­ducing the efficiency of the whole system protec­tion.

The CCITT requirements are different for these
two protection locations (MDFs and line cards).
Concerningthe”primaryprotection”,theCCITTre­quires a 4kV, 10/700µs surge test whereas the
”secondary protection” has to withstand a 1kV,
10/700µs surge test.

The explanations which follow are basically
coveringthelinecardapplication.

Fig. 2 :

Programmablethanks to
any external voltagereference

Linecard protection

I

+I

SWON

-I

Programmablethanks to
an external resistor

SWON

V

Line card operating conditions

The figure 2 summarizes the performance of the
CLP200MwhichbasicallyholdstheSLICinside its
correctvoltageandcurrentvalues.



3/21

CLP200M

APPLICATION CIRCUIT : CLP200Min linecard
Fig.3 : CLP200Min line card

Fuse

TIP

RING

SW3 SW1

FS GND

SW4 SW2

Fuse

R sense

TIPL TIPS

Overcurrent

detector

Overvoltage

detector

Overvoltage

detector

RINGS

RINGL

OR

OR

Overcurrent

R sense

detector

Overvoltage

reference

(+/- 215 V)

Overvoltage

reference

(+/- 215 V)

I

1

Rp

2

1

Rp

2

Ring

Generator

External

voltage

reference

-Vbat

TIP

-Vbat

(*)

SLIC

RING

(*) LCP1511D orTHDT series

Figure 3 above showsthe topology of a protected
analog subscriber line at the exchange side. The
CLP200M is connected to the ring relay via two
balancedRp resistors, and to the SubscriberLine
Interface Circuit. A second device is located near
theSLIC : it canbe either a LCP1511Dor a THDT
series.

These two devices are complementary and their
functionsare explainedbelow:

The first stage based on CLP200M manages
the high power issued from the external
surges. When used in ringing mode, the
CLP200M operates in voltage mode and pro­vides a symmetrical and bidirectional
overvoltage protection at +/-215 V on both TIP
and RING lines. When used in speech mode,
the CLP200M operates in current mode and
the activation current of the CLP200M is ad­justed by R

SENSE

.

The second stage is the external voltage refer­ence device which defines the firing threshold
voltage during the speech mode and also as­sumes a residual power overvoltage
suppression.This protectionstagecan be either
a fixed or programmable breakover device. The
THDTxxfamilyacts as a fixed breakover device
whilethe LCP1511Doperatesas a programma­bleprotection.

Thanks to this topology, thesurge current in the
line is reduced after the CLP200M. Because the
remainingsurgeenergyis low,thepowerratingsof
Rp,the ringrelaycontactsand theexternalvoltage
referencecircuit maybe downsized.This resultsin
a significantcostreduction.

4/21



2.3 Ringingmode
Fig.4 : Switchingbyvoltage duringringingmode.

ILG

Fuse

TIP

FS

Rsense

TIPL TIPS

Overcurrent

detector

OR

SW3 SW1

Overvoltage

detector

1/2 CLP200M

Overvoltage

reference

(+/- 215 V)

VLG

GND

CLP200M

ILG

1

Rp

2

-215

3

A1

2

1

VLG

+215

In ringing mode (Ring relay in position 2), the only
protectiondeviceinvolvedis theCLP200M.

Innormalconditions,theCLP200Moperatesin re­gion1 of A1 curve,andisidle.

If an overvoltageoccuringbetween TIP(or RING)
and GND reaches the internal overvoltage refe­rence(+/- 215V),theCLP200Mactsand thelineis
short-circuited to GND. At this time the operating
pointmovestoregion2 for positive surges(region
3 for negativesurges).Oncethe surgecurrentdis­appears, the device returns to its initial state (re­gion1).

Fig.5a : Methodto adjustthereferencevoltage.

Fuse

TIP

SW3 SW1

R sense

TIPL TIPS

Overcurrent

detector

Overvoltage

OR

detector

For surges occuring between TIP and RING, the
CLP200M acts in the same way. This means that
theCLP200M ensuresa tripolarprotection.

Whenused alone, theCLP200M acts at the inter­nalovervoltagereferencelevel(+/-215V).Further­more,it is possible to adjust this thresholdlevel to
a lowervoltageby using :

.up to 4 fixed external voltage reference (V

V

) (seefig.5a).

Z4

1

Rp

2

VZ1

Overvoltage

reference

(+/- 215 V)

VZ2

Z1

to

RING

FS GND

Fuse

SW4 SW2

RINGL

OR

Overcurrent

detector

R sense

Overvoltage

detector

RINGS



Overvoltage

reference

(+/- 215 V)

VZ3

VZ4

1

Rp

2

5/21

CLP200M

externalreferencesupplies,Vb1andVb2(seefig.5b)..

Fig. 5b: Methodto adjustthe referencevoltage.

TIP

RING

Fuse

R sense

TIPL TIPS

Overcurrent

detector

Overvoltage

OR

SW3 SW1

FS GND

Fuse

SW4 SW2

RINGL

OR

Overcurrent

R sense

detector

detector

Overvoltage

detector

RINGS

Overvoltage

reference

(+/- 215 V)

Overvoltage

reference

(+/- 215 V)

1

Rp

2

VB1

VB2

1

Rp

2

2.4 Speechmode
Fig.6 : Switchingby currentduring speechmode.

ILG

Fuse

TIP

FS

R sense

TIPL TIPS

Overcurrent

detector

OR

SW3 SW1

Overvoltage

detector

Overvoltage

reference

(+/- 215V)

VLG

GND

In speech mode(Ringrelayin position1),the pro­tection is provided by the combination of both
CLP200M and the external voltage reference de­vice.
In normal conditions, the working point of this cir­cuit is located in region 4 of A2 curve : the
CLP200Mis idle.
Whena surgeoccurs on the line,theexternal volt­age reference device clamps at GND or -V

bat

re­spectivelyforpositiveand negativesurges.
This generates a current which is detected by
R

andcausestheprotectiontoact: theline is

SENSE

short-circuitedto GND.

6/21



ILG

1

External

voltage

reference

-Vbat

-VREF2

5

4

VREF1

6

Rp

2

The operatingpoint moves to region 5 for positive
surgesor region6 fornegative surges.
Once the surge current falls below the switching­off current I

, the CLP200M returns to its in-

SWOFF

itialstate (region 4).
Furthermore, the CLP200M switches when an

overvoltage, either positive or negative, occurs
either:

simultaneouslyon bothTIP and RING lines ver­susGND.

betweenTIP andRING.
onTIP (orRING)versus GND.

A2

V

LG

CLP200M

Fig. 7a and 7b : Switching-on current versus

R

.

SENSE

ISWON (mA)

500

300

200

100

3 5 7 9 11 13

Iswon@ 25°C (mA)

500

300

200

100

357911

-20°C25°C75°C

Rsense ( )Ω

Iswonmin Iswon max Iswonmin Iswonmin
negative negative positive positive

Rsense ( )Ω

The choice of the switching-on current is function
oftheR

SENSE

resistors.

In normal operating condition, only the negative
currentofthesignalisof interest.Thiscurrent(typi­cally below -150 mA) should not activate the pro­tection device CLP200M. Therefore the level of
activationis to be chosenjustabove thislimit (typi­cally -200 mA). This level is adjusted through

SENSE

.

R
Figures7a and 7b enablethe designersto choose

theright R

SENSE

value.

2.5. FailureStatus

The CLP200M has an internal feature that allows
the user to get a Failure Status (FS) indication.
When the CLP200M is short-circuiting the line to
GND,a signalcanbemanagedthrough pin 1.This
signalcan beusedto turna LEDon inordertopro­vide a surge indication. It mayalsobe used with a
logic circuitryto count the number of disturbances
appearingon the lines.

Fig. 8 : FailureStatus circuit anddiagnostic.

Rsense

1

FAILURE

STATUS

1k

+12V

CLP200M

Rsense

If a surge exceeding the maximum ratings of the
CLP200Moccurson the line, the devicewill fail in
a short-circuit state.

Fig.9 :

Operationlimitsanddestructionzoneof the

CLP200M.

Ipp (A)

1000

100

10

0.01 0.1 1 10
t (ms)

EXAMPLE :

The choice of R

=4Ωensures a negative

SENSE

triggeringof -220mAmin and-320mAmax.In this
case,thepositivetriggeringwillbe 180mAminand
280mAmax.



Thefigure 9 showstwo differentcurves:

Theloweroneindicatesthe maximumguaranted
workinglimits of the CLP200M.

Theupper curveshowsthelimit abovewhichthe
CLP200Miscompletelydestructed. Inthiscase,
theFail Diagnosticpin is on.

7/21