307C1407 Datasheet, PDF (1/1 Pages) Vishay Siliconix – PTC Thermistors For Electronic Fluorescent Ballasts

307C Lighting Thermistors
Vishay Cera-Mite
PTC Thermistors For Electronic Fluorescent Ballasts
FEATURES
• Electrode preheat thermistors for use in compact
fluorescent lamps (CFL) and electronic ballasts.
• Current limiting, time-delayed start-up extends lamp life.
• Quiet, flicker-free operation.
• Developed in cooperation with leading ballast designers.
• Both standard and custom parts are available.
• Economical, reliable and proven in millions of lamps
throughout the world.
APPLICATION CONSIDERATIONS
• Ignition time can be optimized to increase life of lamp.
• PTC resistance (R₂₅) is chosen, along with filament
resistance and application voltage, to control desired
electrode preheat current.
• Lamp preheat time is determined by time required for
thermistor to switch from low to high resistance state.
Preheat currents shown result in switch times of
approximately 1 second at 25°C. Lower currents result in
longer switch times.
FLUORESCENT LAMP
C
PTC
5mm
max
Tinned Copper Clad Steel Wire
24 AWG when D ≤ 8.5mm
22 AWG when D ≥ 10mm
32mm min
4.5mm
max.
D
LS = 5mm
Options:
• High Temperature Coating
• Short Clipped Leads
• Other Wire Forms and Lead
Spacings
PTC THERMISTORS FOR ELECTRONIC FLUORESCENT BALLASTS
RESISTANCE
R₂₅
(OHMS) 1
150
150
50
70
100
125
150
200
240
300
380
600
600
850
100
150
180
200
300
300
500
800
850
70
70
85
150
85
100
400
INSTANTANEOUS CONTINUOUS
VOLTAGE
VOLTAGE
(V_RMS)
2
(V_RMS) 3
265
80
280
200
175
50
265
150
260
95
230
80
235
90
320
145
350
150
400
165
410
170
420
120
460
200
450
340
340
265
340
150
350
165
355
265
370
75
420
320
480
400
530
450
520
175
210
50
300
140
210
50
400
100
280
60
310
90
430
120
PREHEAT
CURRENT
(mA) 4
215
200
430
350
370
280
260
300
260
225
205
185
170
140
390
400
380
300
270
230
190
155
190
750
725
670
550
820
750
420
D
MAX.
(mm) 5
4.5
4.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
7
7
7
7
7
7
7
7
7
8.5
8.5
8.5
8.5
10
10
10
PART
NUMBER 6
307C1407
307C1414
307C1230
307C1654
307C1364
307C1259
307C1253
307C1223
307C1171
307C1225
307C1390
307C1252
307C1224
307C1622
307C1403
307C1306
307C1569
307C1375
307C1242
307C1360
307C1361
307C1362
307C1260
307C1367
307C1366
307C1363
307C1287
307C1258
307C1365
307C1422
Note 1: R₂₅ - Nominal zero power resistance ± 25% at 25°C. For given diameter, higher resistance thermistors offer higher maximum voltages.
Note 2: Instantaneous Voltage - Maximum rms voltage permitted across thermistor during fluorescent lamp start-up cycle.
Note 3: Continuous Voltage - Maximum rms voltage continuously applied across thermistor during normal lamp operation.
Note 4: Preheat Current - rms current (60Hz) which switches thermistor to high resistance in approximately 1 second at 25°C ambient.
Note 5: Size (mass) of PTC influences rate of I²R temperature increase. For given resistance, larger thermistors have longer switch times.
Optional coating slightly increases switch time.
Note 6: P/N suffix (not shown) describes wire lead forms and other options.
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Document Number: 23088
Revision 14-May-02