307C1305 [VISHAY]
PTCR Overcurrent Protection; PTCR过流保护
| 型号： | 307C1305 |
| 厂家： | 
VISHAY |
| 描述： | PTCR Overcurrent Protection |
| 文件： | 总5页 (文件大小：120K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
307C Overcurrent Thermistors
Vishay Cera-Mite
PTCR Overcurrent Protection
FEATURES:
A NEW DIMENSION
Sizes For Your Application - Hold currents from 5 mA to 1.5 A are available
in sizes from 4 to 22mm.
The Positive Temperature Coefficient
Resistor’s (PTC thermistor) unique property
of dramatically increasing its resistance
above the curie temperature makes it
an excellent candidate for overcurrent
protection applications. Overcurrent
situations in electronic devices occur
due to voltage fluctuations, changes in
load impedance, or problems with system
wiring. PTC thermistors monitor current in
series connected loads, trip in the event
of excess current, and reset after the
overload situation is removed, creating a
new dimension of flexibility for designers.
Better Protection, Maintenance Free - PTCRs reset after an overcurrent
situation. Protection levels may be set lower than possible with fuses, without
worrying about nuisance trips.
Resetting, Non Cycling - Functioning as a manual reset device, PTCR
overcurrent protectors remain latched in the tripped state and automatically
reset only after voltage has been removed. This prevents continuous cycling,
and protects against reclosing into a fault condition.
Simplified Mounting - PTCRs may be mounted directly inside end use
equipment. Unlike fuses, no bulky fuseholder or access for user replacement
is required.
Ceramic Material Selection - Various curie materials are available to tailor
hold and trip current operating points.
Repeatable, No Hysteresis - After resetting, ceramic PTCRs return to the
initial resistance value, providing repeatable, consistent protection levels.
Unlike polymer type PTCRs, Vishay Cera-Mite devices exhibit no resistance
hysteresis application problems.
APPLICATIONS:
• Telecommunication Products
• Electronic Power Supplies
• Automotive Motor Protection
• Industrial Control Systems
Telecom Line Balance - In telecom circuits matched pairs are used to
maintain line balance. Unlike polymer PTCRs, ceramic devices maintain
balance after resetting.
APPLICATION DATA
This relationship is shown in Fig P-2,
which provides hold current (IH) derating
estimates for ambient temperatures in
excess of 25°C. Five curie materials
illustrate the design flexibility offered by
ceramic PTCR’s.
In a typical current limiter application, the PTC device is connected in series
with a load impedance (Fig P-1). When current (I) flows, internal I2R losses
attempt to increase the PTCR’s temperature. To maintain the low resistance
“on” state, stabilization must occur below the switching temperature, where
the heat generated (I2R) is balanced by heat lost due to radiation and
conduction.
Hold current (IH) is the maximum continuous current at which a PTCR can
be maintained in a low resistance “on” state while operating at rated ambient
temperature (typ 25°C). To prevent nuisance tripping, choose the rated hold
current to be greater than the normal current expected.
Fig P-2
PTC Thermistor Overcurrent Protectors
Ambient Temperature Derating of Hold and
Trip Currents
Since heat dissipated by the device is proportional to the ambient temperature,
hold current must be derated for ambients higher than 25°C according to
the following relationship:
140%
70°C Curie Material
80°C Curie Material
120%
90°C Curie Material
105°C Curie Material
120°C Curie Material
100%
80%
60%
40%
20%
0%
Hold Current (IH) = D(TSW - TA)
RPTC
Where:
Fig P-1
D
= Dissipation Constant
(varies based on disc
size, wire type, &
Typical PTC Current Limiter Application
PTC
coating material)
-10
0
10 20 30 40 50 60 70 80 90 100 110 120
Ambient Temperature (°C)
AC
or
DC
TSW = Switching (Curie)
Temperature of
V
LOAD
PTCR Material
TA = Ambient Temperature
R
PTC= Resistance of PTCR
at 25°C
Document Number: 23089
Revision 14-May-02
www.vishay.com
11
ceramite.support@vishay.com
307C Overcurrent Thermistors
PTCR Overcurrent Protection
Vishay Cera-Mite
APPLICATION DATA
TRIPPING ACTION DUE TO OVERCURRENT
During normal operation, the PTCR remains in a low base
resistance state (Fig P-3, Region 1). However, if current
in excess of hold current (IH) is conducted, I2 R losses
produce internal self heating. If the magnitude and time of
the overcurrent event develops an energy input in excess of
the device’s ability to dissipate heat, the PTCR temperature
will increase, thus reducing the current and protecting the
circuit.
Since the tripping operation is due to thermal change, there
is a time-trip curve associated with each device. At relatively
low magnitudes of overcurrent, it may take minutes for the
device to trip. Higher current levels can result in millisecond
response time. Trip time (t) can be calculated as follows
kM(TSW -TA)
Trip Time (t) =
I2 R - D(TSW-TA)
Where: k = coefficient of heat absorption = 0.603 J/g/°C
M = mass of PTCR = volume x 5.27x10 - 3 g/mm3
R = zero power resistance of PTCR at 25°C
PTC current limiters are intended for service on telecom
systems, automobiles, or the secondary of control transform-
ers or in similar applications where energy available is limited
by source impedance. They are not intended for application
on AC line voltages where source energy may be high and
source impedance low.
Fig P-3
PTC
RESISTANCE
100000
The current required to trip (IT) is typically specified as two
times the hold current (2 x IH). IT is defined as the minimum
rms conduction current required to guarantee thermistor
switching into a high resistance state (Fig P-3, Region 2) at
a 25°C ambient temperature.
10000
REGION 1
BASE
REGION 2
HIGH
Ambient temperature influences the ability of the PTCR to
transfer heat via surface radiation and thermal conduction at
the wire leads. At high ambient temperatures, less energy
input (via I2R) is required to reach the trip temperature. Low
ambients require greater energy input. Approximate derating
effects are shown in Fig P-2.
1000
100
RESISTANCE
RESISTANCE
RSW
=
2 x R25
CERAMIC MATERIALS
The temperature at which the PTCR changes from the
base resistance to high resistance region is determined by
R25
10
TSW
R vs. T Operating Characteristics
PTC
Temperature
25°C
the PTCR ceramic material. Switching temperature (TSW
)
described by the boundary between regions 1 & 2 (Fig P-3),
is the temperature point at which the PTCR has increased
to two times its base resistance at 25°C ambient (RSW = 2
PHYSICAL DESIGN CONSIDERATIONS
Diameter (D) - Common diameters range from 4 to 22mm.
Thickness (T) - Typical thickness ranges from 1 to 5mm.
Curie (Switching) Temperature (TSW) - See Fig P-4.
Resistivity (ρ) -
x R ). Design flexibility is enhanced by Cera-Mite’s wide
25
selection of ceramic PTCR materials with different switching
temperatures (Fig P-4).
Fig P-4
100K
Determined during sintering process; combined
with pellet geometry results in final resistance
based on:
Vishay Cera-Mite offers
a wide selection of
10K
1K
ceramic PTC materials
providing flexibility for
different ambient
ρT
R25 = zero power resistance at 25°C =
Area
temperatures. Close
protection levels are
possible by designing
resistance and physical
size to meet specific
hold current and trip
current requirements.
Table 2
100
10
How Various Physical Parameters Influence
a
PTCs:
HOLD CURRENT & TRIP TIME
Increased diameter will increase
hold current and lengthen trip time.
Increased thickness will increase
hold current and lengthen trip time.
PARAMETER
Disc Diameter (D)
VOLTAGE & CURRENT CAPABILITY
Increased diameter will increase voltage
and current ratings.
Increased thickness will increase
voltage rating; may or may not
increase current rating.
Disc Thickness (T)
2.0
1.0
Curie (Switch) (TSW
Temperature
)
Typically, lower switch temperature
materials have higher voltage/
current capability.
Higher switch temperature
materials increase hold current
and lengthen trip time.
0.1
Curie Temperature °C (±5°)
Resistance (R25
)
Higher resistance will increase
voltage capability.
Increased thermal loading typically
reduces the maximum interrupting current. hold current and lengthens trip times.
Wire leads added to a PTCR pellet act as Depends on thermal conductivity of
a thermal load resulting in reduced
maximum interrupting current.
Lower resistance will increase hold
current and lengthen trip times.
Increased thermal loading increases
SELF RESETTING - NON CYCLING - REPEATABLE
After tripping, the PTCR will remain latched in its high
resistance state as long as voltage remains applied and
sufficient trickle current is maintained to keep the device
above the switching temperature. After voltage is removed,
the PTCR resets (cools) back to its low resistance state and
is again ready to provide protection.
Thermal Loading
(Heat Sink)
Wire Leads
wire used. Copper will increase
hold current and trip time.
Applying coating to a leaded PTCR
increases hold current/trip time 10-20%.
Coating Material
Applying coating to a leaded PTCR has
minimal effect on voltage/current ratings.
www.vishay.com
12
Document Number: 23089
Revision 14-May-02
ceramite.support@vishay.com
307C Overcurrent Thermistors
PTCR Overcurrent Protection
Vishay Cera-Mite
Fig P-6
Fig P-5
PTC THERMISTORS FOR
TELECOMMUNICATIONS
C.O. Ring
C.O.
Tip
Ground
Over-Current
PTC Thermistors provide protection
for large digital switches.Vishay Cera-
Mite has pioneered this field with
ceramic PTC thermistors working
closely with major telephone equip-
ment and telephone protection
manufacturers. The requirements are
dynamic, as switch makers continually
strive to protect at lower levels.Vishay
Cera-Mite participates with industry
standard technical committees to
establish common definitions and
understanding of this new tech-
nology.
Line
Tip
Pressure
Contact
Leaded PTCR
Pressure
Contact
Over-voltage
PTCR
C.O. Tip
OV
PTCR
Line Tip
C.O. Tip
OV
C.O. Ring
PTCR
PTCR
To Battery
C.O. Ring
Line Ring
Fig P-8
PTC THERMISTOR PELLETS FOR TELECOMMUNICATIONS
Table 2
Time-Trip Curves for Popular Telecom Pellets
100
PTCR
Scope
VISHAY
Fig P-7
HOLD (IH) TRIP (IT) RESISTANCE SWITCH SIZE (D) CERA-MITE
Solid Ceramic
Disc
RL
CURRENT CURRENT
R25
Ohms
30
TEMP. NOMINAL
PART
1/2
mA
mA
°C
105
70
mm
6.5
8
NUMBER
Time To
110
100
100
110
120
140
110
130
140
150
220
200
200
220
240
280
220
260
280
300
307C1127
307C1128
307C1126
307C1268
307C1129
307C1435
307C1134
307C1130
307C1436
307C1437
Note 3
Base
Electrode
10
15
D
307C1130
20
80
8
307C1129
307C1128
307C1126
307C1127
Silver
Electrode
18
80
8
15
80
8
15
15
15
9
105
70
80
70
80
8
1
T
9.5
9.5
9.5
9.5
2.5mm
Rated Voltage = 60 VDC
Rated Current = 3A
10
Maximum Voltage = 220 Vrms
Note 1
Note 2
0.1
0
.05
1
1.5
Current (Amperes)
Operating Time to 50% Current
2
2.5
3
Note 1
Hold and trip currents
are specified at
Note 3
Note 2
25 is nominal zero power
resistance at 25°C with
All pellets have silver elec-
trodes suitable for pressure
contact mounting.
R
25°C ambient.
tolerance of ± 20%.
Fig P-10
INTERRUPTING CAPACITY ESTIMATES
Under unusual circumstances, telecommunication lines may
be subjected to high surge currents as might occur from
lightning effects or accidental crossing with power lines or
transformer primaries.
Time VS. Current Curves for High Current Surges (25°C)
10,000
10 ohm, 80°C Pellets for
Diameters (mm
Fig P-10 shows trip time curves for higher currents.Estimated
interrupting capability data is also shown in Table 3 and
is expressed as “I2 t Let Through” based on test data
conducted in accordance with UL 497A and CSA 22.2 No.
0.7-M1985.
14.5mm
12.5mm
11.0mm
9.5mm
8.0mm
6.5mm
1,000
The data shown is for reference. Specific short circuit data or
interrupting capability is partially determined by the mounting
means and circuit application.
100
Fig P-9
15
85
275
PTCR
Current
Limiter
A
B
C
Variable
Voltage
Source
0-600V
60Hz
Current
Probe or
26 AWG
Pair
A = 1.5 sec.
10
Timed Interrupter B = 5 sec.
C = 30 min.
2
4
6
8
10
12
14
16
18
20
Current (Amperes)
2 t Let Through
Document Number: 23089
Revision 14-May-02
www.vishay.com
13
ceramite.support@vishay.com
307C Overcurrent Thermistors
PTCR Overcurrent Protection
Vishay Cera-Mite
Table 3
CUSTOM PTCR PELLET
DESIGN CAPABILITY
RATING CHART FOR CUSTOM PELLETS
DISC DIAMETER (2.5mm THICK) 6.5mm
• Vishay Cera-Mite will customize
solid state overcurrent protector
PTCRs to your exact requirements
for telecommunication, power
supply, or general electronic
use. Providing great flexibility to
establish specific voltage, hold
current, time-trip characteristic, and
ambient temperature values.
8mm
9.5mm
11mm
12.5mm 14.5mm
Continuous Voltage Rating (rms)
(proportional to resistance)
100 – 300 100 – 300100 – 300 100 – 300 100 – 300 50 - 300
Resistance Range @ 25°C (ohms) 10 to 35 7 to 25 5 to 20
4 to 17
2 to 15
1 to 10
Continuous Carry Current (mA)
Ambient 25° to 50°C (inversely
proportional to resistance)
60 – 120 75 – 175 100 – 200 110 – 250 130 – 400 150 – 600
Approximate Minimum Power
to Trip or Reset (watts)
• Each device must be evaluated
and ratings established per appli-
cation. Mechanical packaging
influences performance ratings.
0.4
0.5
0.6
0.7
0.8
0.9
Interrupting Capability
A. Repetitive (25 to 300 VRMS
Peak power in watts
)
600
2.5
700
4.0
800
7.5
900
15
1000
20
1100
30
B. Non-repetitive (for 10 ohm
pellet) I2 t Let Through
Maximum Safe Interrupting
Voltage (rms) (voltage rating
is proportional to resistance)
300
350
400
450
500
600
Rating applies to pellets with silver electrodes and pressure connections.
TRANSIENT VOLTAGE &
CURRENT
Fig P-11
Because of the thermal storage
capacity of the ceramic PTCR,
transient surges do not cause tripping.
The PTCR is considered to be
transparent to these low energy
transients. Fig P-11 shows a typical
test circuit for such transients.
1000
10 x 1000µ sec.
PTCR
± 1000V peak
Pass-Thru Pulse
Table 4
WIRE LEADED PTC
TELECOM THERMISTORS
TELECOM CURRENT LIMITERS
Resettable current limiters featuring
hold current and voltage ratings for
telecommunication applications.
VISHAY
CERA-MITE
PART
Note 1
Hold and trip
currents specified at
25°C ambient.
HOLD (IH) TRIP (IT) RESISTANCE SWITCH SIZE (D)
MAX.
CURRENT CURRENT
R25
TOL. TEMP. NOMINAL VOLTAGE
VRMS
mA
mA
Ohms
%
°C
mm
NUMBER
70
140
200
200
220
220
240
240
240
260
240
240
300
240
250
270
300
340
220
250
100 25
120
80
105
80
105
80
105
120
80
120
105
90
80
105
80
6.5
8
8
8
8
8
8
8
8
8.7
8.7
8.7
9.5
9.5
9.5
9.5
11.2
14.5
14.5
265
220
220
220
220
220
220
220
120
250
250
110
220
220
220
220
220
300
265
307C1418
307C1305
307C1506
307C1354
307C1514
307C1129
307C1296
307C1470
307C1421
307C1505
307C1501
307C1439
307C1465
307C1507
307C1469
307C1233
307C1234
307C1262
307C1254
Fig P-12
100
100
110
110
120
120
120
130
120
120
150
120
125
135
150
170
110
125
20
30
18
25
15
20
25
13
39
25
12
15
20
10
10
10
23
18
20
20
20
20
20
20
20
20
30
25
20
25
20
25
20
20
20
25
Note 2
Tinned Copper Wire
22 AWG Standard
20 AWG on D=14.5mm
R
is nominal zero
25
power resistance
(± 25%) at 25°C.
5mm
max
Note 3
P/N suffix describes
options including:
Tape & Reel
Wire Size
Wire Style &
Length
32mm min
4.5mm
max
D
LS = 5mm
105
105
80
Lead Spacing
Coating Material
80
Note 1
Note 2
Note 3
Rated Voltage = 60Vdc; Rated Current = 3A at rated voltage.
www.vishay.com
14
Document Number: 23089
Revision 14-May-02
ceramite.support@vishay.com
307C Overcurrent Thermistors
PTCR Overcurrent Protection
Vishay Cera-Mite
GENERAL PURPOSE
Table 5
PTC CURRENT LIMITERS
• Designed as resettable current
limiters, PTC thermistors offer an
alternative to conventional over-
current protection devices such as
fuses or circuit breakers.
GENERAL PURPOSE PTC THERMISTORS OVERCURRENT PROTECTORS
VISHAY
RATED
MAX.
HOLD (IH
)
TRIP (IT)
MAX.
RES
R25
Ohms
SWITCH
TEMP
°C
D
MAX.
mm
CERA-MITE
PART
VOLTAGE VOLTAGE CURRENT
CURRENT CURRENT
VRMS
VRMS
mA
mA
A
NUMBER
12
12
12
24
24
24
50
50
50
15
15
15
30
30
30
60
60
60
130
170
600
130
175
600
60
120
150
325
475
60
85
95
115
105
350
20
28
31
34
40
45
55
65
90
260
340
1200
260
350
1200
120
240
300
650
950
120
170
190
230
210
700
40
1.1
2.4
10
2.3
3.4
11
0.8
2
2.6
10
13
6
1.2
10
6
1.3
50
12
10
3.5
2
50
30
39
27
20
4.5
600
300
240
200
125
150
100
70
120
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
105
5.5
8
16
8
307C1455
307C1308
307C1311
307C1315
307C1429
• A wide variety of sizes and current
ranges are available for many
electronic, industrial and automotive
applications. Both standard parts and
custom designs are offered.
9.5
17.5 307C1318
6.5
8
307C1321
307C1323
307C1548
Fig P-13
9.5
Tinned Copper Clad Steel Wire
50
50
60
60
14.5 307C1325
17.5 307C1326
6.5
8
24 AWG when D < 9.5mm
22 AWG when D > 11mm to < 19mm
20 AWG when D > 21mm
12
120
120
120
120
120
120
240
240
240
240
240
240
240
240
240
140
140
140
140
140
140
375
340
310
265
265
320
320
265
265
0.6
0.8
1.5
2
1
5
0.2
0.3
0.33
0.34
0.45
0.4
0.5
0.6
1
307C1329
307C1330
307C1302
5mm
max
11
12.5 307C1303
9.5
19
6.5
6.5
6.5
6.5
6.5
9.5
11
307C1331
307C1333
307C1335
307C1336
307C1337
307C1338
307C1340
307C1339
307C1341
307C1342
307C1343
Note 3
4.5mm
max
56
62
68
80
D
CL
LS
90
CL - Cut Leads are Standard 4.75± 0.5mm
LS - Standard Lead Spacings:
110
130
180
9.5
11
5mm when
7.5mm when
10mm when
D ≤11mm
D = 12.5 to 17.5mm
D ≥19mm
45
Note 2
Note 1
CUSTOM CURRENT LIMITER GUIDELINES
APPLICATION CONSIDERATIONS:
Table 6
• PTC current limiters are intended for service on
telecom systems, automobiles, or the secondary of
control transformers or in similar applications where
energy available is limited by source impedance.They are
not intended for application on AC line voltages where
source energy may be high and source impedance low.
RANGE CHART FOR CUSTOM WIRE LEADED DESIGN
MAX.
D (mm)
COATED
5.5
DESIGN LIMITS (APPROX.)
MAX.
D (mm)
COATED
17.5
DESIGN LIMITS (APPROX.)
VRMS
600
15
600
15
I HOLD
5 mA
150 mA
7 mA
OHMS
2000
13
1200
8
VRMS
600
15
I HOLD
40 mA
950 mA
45 mA
1.1 A
OHMS
125
0.8
100
0.7
80
• Fuses and circuit breakers result in total circuit
isolation after tripping. PTC thermistors provide a
current limiting function by switching to a high
resistance mode. Safety consideration must be given
to the potential shock hazard caused by the steady
state leakage current and voltage potential remaining in
the circuit.
19
21
600
15
6.5
8
200 mA
10 mA
275 mA
13 mA
350 mA
20 mA
450 mA
22 mA
500 mA
30 mA
650 mA
35 mA
800 mA
600
15
55 mA
1.2 A
600
15
850
6
0.6
70
0.5
60
0.45
50
0.4
22.5
23.5
25
600
15
600
15
600
15
60 mA
1.3 A
70 mA
1.4 A
80 mA
1.5 A
9.5
11
600
15
600
15
600
15
600
15
500
4
• Wire leaded PTC current limiting thermistors are intended
for applications which expect a limited number of tripping
operations.Actual life is a function of operating parameters.
For high duty cycle applications, ceramic PTC pellets
mounted in spring contact mechanical housings are
preferred.
350
2.5
250
2.0
200
1.5
150
1.2
12.5
14.5
16
Resistance is proportional
to voltage and inversely
proportional to hold
• Wire size, wire type and coating material can be used to
precisely tailor required operating characteristics.
600
15
current (IH
)
Conformal coating adds 1.5mm
• Options Include: Tape & Reel; Wire Forms; Lead
Spacings.
Document Number: 23089
Revision 14-May-02
www.vishay.com
15
ceramite.support@vishay.com
相关型号：
307C1306R
RESISTOR, TEMPERATURE DEPENDENT, PTC, 150 ohm, THROUGH HOLE MOUNT, RADIAL LEADED, ROHS COMPLIANT
VISHAY
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