PTCLL

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Revision: 30-Nov-15

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Document Number: 29071

THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT

PTC Thermistors, Time Delay for Lighting

DESCRIPTION

Positive temperature coefficient (PTC) thermistors for

overload protection have proved to be the ideal electronic

ballast component for increased lamp life-time.

When the rectified mains is first applied, the PTC thermistor

is cold, so its resistance is low. The lamp voltage will be

below the necessary ignition value, so the current will flow

through the cathodes, heating them to their emission

temperature. At the same time, the PTC thermistor will heat

up to its switch temperature, whereupon its resistance will

rise rapidly, allowing the lamp voltage to reach its ignition

value and light the lamp.

Once the lamp is lit, the cathodes are fed by a

high-frequency lamp supply, to avoid flicker and improve

efficiency. The PTC thermistor plays no further part until the

lamp is switched off, whereupon it is ready to resume its

smooth-starting function.

We supply a range of lighting PTC thermistors for this

application offering a wide choice of voltage and switch

times.

FEATURES

• Reliable lamp starting, due to well defined

inrush-current generated time delay

• Accurate resistance for ease of circuit design

• Small size and durable

• Available bulk-packed or taped-on-reel

• Long life: More than 20 000 starts for a 20 W

CFL lamp

• Material categorization: for definitions of compliance

APPLICATIONS

Fluorescent lighting and lighting ballasts for:

• CFL 5 to 25 W range

• TL HF-ballasts

MOUNTING

The leads are suitable for soldering in any position. The

lacquer may cover the leads up to 1.0 mm from the seating

plane.

Notes

QUICK REFERENCE DATA

PARAMETER

VALUE

UNIT

Rated voltage (RMS)

80 to 200

Nominal switching current

150 to 500

mA

Resistance at 25 °C (

100 to 625

Ω

Tolerance on

20 to 30

%

0.5 to 1.0

A

Tripping time

0.3 to 1

s

Operating temperature range

at rated voltage

-20 to 105

°C

ELECTRICAL DATA AND ORDERING INFORMATION

(Ω)

SWITCH

TEMPERATURE

(°C)

MAXIMUM

TRIP TIME at 25 °C

CATALOG NUMBER

MIN.

MAX.

(s)

(mA)

SAP CODING

500

750

≈ 110

700

0.4

200

185

300

≈ 120

700

0.5

300

75

125

≈ 80

700

0.7

300

225

375

≈ 105

900

0.75

300

75

125

≈ 105

1 000

0.85

500