EPCOS ICL_B57235_S235

NTC thermistors for
inrush current limiting
Leaded and coated disks
Series/Type:
B57235S0***M0**
Date:
December 2011
© EPCOS AG 2011. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS' prior express consent is prohibited.
Inrush current limiters
B57235S0***M0**
ICLs
S235
Applications
Switch-mode power supplies
Dimensional drawing
Features
Useable in series connections up to 265 VRMS
Coated thermistor disk
Kinked leads of tinned copper wire
Wide resistance range
Small space requirement
Cost-effective
UL approval (E69802)
Dimensions in mm
Approx. weight 0.8 g
Options
Resistance tolerance <20% and alternative lead
configurations available on request
Delivery mode
Bulk (standard) or with cardboard tape on 350-mm reel
General technical data
Climatic category
Max. power
Resistance tolerance
Rated temperature
Dissipation factor
Thermal cooling time constant
Heat capacity
(IEC 60068-1)
(at 25 °C)
(in air)
(in air)
Pmax
∆RR/RR
TR
δth
τc
Cth
55/170/21
1.8
±20
25
approx. 9
approx. 60
approx. 540
Param.
for R(I)1)
k
0.700
0.710
0.757
0.814
0.879
Param.
for R(I)1)
n
1.30
1.30
1.30
1.32
1.32
W
%
°C
mW/K
s
mJ/K
Electrical specification and ordering codes
R25
Ω
4.7
5
6
8
10
Imax
(0...65 °C)
A
4.4
4.2
4.0
3.5
3.0
B25/100
K
2800
2800
2800
2900
2900
Ctest1)
230 V AC
µF
200
200
200
200
200
Ctest1)
110 V AC
µF
800
800
800
800
800
Ordering code
B57235S0479M0**
B57235S0509M0**
B57235S0609M0**
B57235S0809M0**
B57235S0100M0**
** = Delivery mode
00 = Bulk
51 = Reel packing
1) For details on the capacitance Ctest as well as on the parameters k and n refer to "Application notes", chapters 1.6 and 1.7.
Please read Cautions and warnings and
Important notes at the end of this document.
Page 2 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Reliability data
Test
Standard
Storage in
dry heat
IEC
60068-2-2
Storage in damp
heat, steady state
Rapid temperature
cycling
Endurance
Cyclic
endurance
Transient
load
Test conditions
Storage at upper
category temperature
T: 170 °C
t: 1000 h
IEC
Temperature of air: 40 °C
60068-2-78 Relative humidity of air: 93%
Duration: 21 days
IEC
Lower test temperature: 55 °C
60068-2-14 Upper test temperature: 170 °C
Number of cycles: 10
I = Imax
t: 1000 h
I = Imax, 1000 cycles
On-time = 1 min
Cooling time = 6 min
Capacitance = Ctest
Number of cycles: 1000
∆R25/R25
(typical)
< 10%
Remarks
< 5%
No visible
damage
< 10%
No visible
damage
< 10%
No visible
damage
No visible
damage
< 10%
< 5%
No visible
damage
No visible
damage
Note
The self-heating of a thermistor during operation depends on the load applied and the
applicable dissipation factor.
When loaded with maximum allowable current/power and the specified dissipation factor is
taken as a basis, the NTC thermistor may reach a mean temperature of up to 250 °C.
The heat developed during operation will also be dissipated through the lead wires. So the
contact areas, too, may become quite hot at maximum load.
When mounting NTC thermistors you have to ensure that there is an adequate distance
between the thermistor and all parts which are sensitive to heat or combustible.
Please read Cautions and warnings and
Important notes at the end of this document.
Page 3 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Taping and packing
1
Taping of radial leaded ICL NTC thermistors according to the
specified lead spacing
Dimensions and tolerances
Lead spacing F = 5.0 mm (taping to IEC 60286-2)
Lead spacing F = 7.5 mm (taping based on IEC 60286-2)
Please read Cautions and warnings and
Important notes at the end of this document.
Page 4 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Dimensions (mm)
Lead
spacing
5 mm
Tolerance of
lead spacing
5 mm
Lead
spacing
7.5 mm
Tolerance of
lead spacing
7.5 mm
Remarks
w
≤12.0
max.
≥12.0
max.
please refer to dimensional
drawings
th
6.0
max.
7
max.
please refer to dimensional
drawings
d
0.5/0.6
±0.05
0.8/1.0
±0.05
please refer to dimensional
drawings
P0
12.7
±0.3
12.7
±0.3
±1 mm / 20 sprocket holes
P1
3.85
±0.7
8.95
±0.8
F
5.0
+0.6/0.1
7.5
±0.8
∆h
0
±2.0
0
∆p
0
±1.3
0
±2.0
W
18.0
±0.5
18.0
±0.5
W0
5.5
min.
11.0
min.
W1
9.0
+0.75/0.5
9.0
+0.75/0.5
Depends on th measured at top
of component body
W2
3.0
max.
3.0
max.
H
18.0
+2.0/0
18.0
+2.0/0
H0
16.0
±0.5
16.0
±0.5
H1
32.2
max.
45.0
max.
D0
4.0
±0.2
4.0
±0.2
t
0.9
max.
0.9
max.
L
11.0
max.
11.0
max.
L1
4.0
max.
4.0
max.
Please read Cautions and warnings and
Important notes at the end of this document.
Page 5 of 14
peel-off force ≥5 N
without wires
Inrush current limiters
B57235S0***M0**
ICLs
S235
Types of packing
Reel packing
Reel dimensions (in mm)
Reel type
d
f
n
w
I
360 max.
31 ±1
approx. 45
54 max.
II
500 max.
23 ±1
approx. 59
72 max.
Bulk packing
The components are packed in cardboard boxes, the size of which depends on the order quantity.
Please read Cautions and warnings and
Important notes at the end of this document.
Page 6 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Mounting instructions
1
Soldering
1.1
Leaded NTC thermistors
Leaded thermistors comply with the solderability requirements specified by CECC.
When soldering, care must be taken that the NTC thermistors are not damaged by excessive
heat. The following maximum temperatures, maximum time spans and minimum distances have
to be observed:
Dip soldering
Iron soldering
Bath temperature
max. 260 °C
max. 360 °C
Soldering time
max. 4 s
max. 2 s
Distance from thermistor
min. 6 mm
min. 6 mm
Under more severe soldering conditions the resistance may change.
Solderability (test to IEC 60068-2-20)
Preconditioning: Immersion into flux F-SW 32.
Evaluation criterion: Wetting of soldering areas ≥95%.
Solder
Bath temperature (°C)
Dwell time (s)
SnAg (3.0 ... 4.0), Cu (0.5 ... 0.9)
245 ±3
3
1.1.1
Resistance to soldering heat (test to IEC 60068-2-20)
Preconditioning: Immersion into flux F-SW 32.
Solder
Bath temperature (°C)
Dwell time (s)
SnAg (3.0 ... 4.0), Cu (0.5 ... 0.9)
260 5
10
Please read Cautions and warnings and
Important notes at the end of this document.
Page 7 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Wave soldering
Temperature characteristic at component terminal with dual wave soldering
2
Robustness of terminations
The leads meet the requirements of IEC 60068-2-21. They may not be bent closer than 4 mm
from the solder joint on the thermistor body or from the point at which they leave the feedthroughs. During bending, any mechanical stress at the outlet of the leads must be removed. The
bending radius should be at least 0.75 mm.
Tensile strength:
Test Ua1:
Leads
0.50 < ∅ ≤0.80 mm = 10.0 N
0.80 < ∅ ≤1.25 mm = 20.0 N
Bending strength: Test Ub:
Two 90°-bends in opposite directions at a weight of 0.25 kg.
Torsional strength: Test Uc: severity 2
The lead is bent by 90° at a distance of 6 to 6.5 mm from the thermistor body.
The bending radius of the leads should be approx. 0.75 mm. Two torsions of
180° each (severity 2).
Please read Cautions and warnings and
Important notes at the end of this document.
Page 8 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
When subjecting leads to mechanical stress, the following should be observed:
Tensile stress on leads
During mounting and operation tensile forces on the leads are to be avoided.
Bending of leads
Bending of the leads directly on the thermistor body is not permissible.
A lead may be bent at a minimum distance of twice the wire's diameter +2 mm from the solder
joint on the thermistor body. During bending the wire must be mechanically relieved at its outlet.
The bending radius should be at least 0.75 mm.
Twisting of leads
The twisting (torsion) by 180° of a lead bent by 90° is permissible at 6 mm from the bottom of the
thermistor body.
3
Sealing and potting
When thermistors are sealed, potted or overmolded, there must be no mechanical stress caused
by thermal expansion during the production process (curing / overmolding process) and during
later operation. The upper category temperature of the thermistor must not be exceeded. Ensure
that the materials used (sealing / potting compound and plastic material) are chemically neutral.
4
Cleaning
If cleaning is necessary, mild cleaning agents such as ethyl alcohol and cleaning gasoline are
recommended. Cleaning agents based on water are not allowed. Ultrasonic cleaning methods are
permissible.
5
Storage
In order to maintain their solderability, thermistors must be stored in a non-corrosive atmosphere.
Humidity, temperature and container materials are critical factors.
The components should be left in the original packing. Touching the metallization of unsoldered
thermistors may change their soldering properties.
25 °C up to 45 °C
Storage temperature:
Max. relative humidity (without condensation):
<95%, maximum 30 days per annum
Solder the thermistors listed in this data book after shipment from EPCOS within the time specified:
Leaded components:
Please read Cautions and warnings and
Important notes at the end of this document.
24 months
Page 9 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Cautions and warnings
General
See "Important notes" at the end of this document.
Storage
Store thermistors only in original packaging. Do not open the package before storage.
Storage conditions in original packaging: storage temperature 25 °C ... +45 °C, relative
humidity ≤75% annual mean, maximum 95%, dew precipitation is inadmissible.
Avoid contamination of thermistors surface during storage, handling and processing.
Avoid storage of thermistor in harmful environments like corrosive gases (SOx, Cl etc).
Solder thermistors after shipment from EPCOS within the time specified:
Leaded components: 24 months
Handling
NTC thermistors must not be dropped. Chip-offs must not be caused during handling of NTCs.
Components must not be touched with bare hands. Gloves are recommended.
Avoid contamination of thermistor surface during handling.
In case of exposure of the NTC thermistors to water, electrolytes or other aggressive media,
these media can penetrate the coating and reach the surface of the ceramic. Low-ohmic or
high-ohmic behavior may occur due to the formation of an electrolyte with metals (silver/lead/tin
from metallization or solder). Low-ohmic behavior is caused by electrochemical migration,
high-ohmic behavior by dissolving of the electrode. Ineither case, the functionality of the NTC
thermistors can not be assured.
Bending / twisting leads
A lead (wire) may be bent at a minimum distance of twice the wire’s diameter plus 4 mm from
the component head or housing. When bending ensure the wire is mechanically relieved at the
component head or housing. The bending radius should be at least 0.75 mm.
Twisting (torsion) by 180° of a lead bent by 90° is permissible at 6 mm from the bottom of the
thermistor body.
Soldering
Use resin-type flux or non-activated flux.
Insufficient preheating may cause ceramic cracks.
Rapid cooling by dipping in solvent is not recommended.
Complete removal of flux is recommended.
Please read Cautions and warnings and
Important notes at the end of this document.
Page 10 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Mounting
When NTC thermistors are encapsulated with sealing material or overmolded with plastic
material, the precautions given in chapter “Mounting instructions”, “Sealing and potting” must
be observed.
Electrode must not be scratched before/during/after the mounting process.
Contacts and housings used for assembly with thermistor have to be clean before mounting.
During operation, the inrush current limiters surface temperature can be very high. Ensure that
adjacent components are placed at a sufficient distance from the thermistor to allow for proper
cooling of the thermistors.
Ensure that adjacent materials are designed for operation at temperatures comparable to the
surface temperature of the thermistor. Be sure that surrounding parts and materials can
withstand this temperature.
Make sure that inrush current limiters are adequately ventilated to avoid overheating.
Avoid contamination of thermistor surface during processing.
Operation
Use thermistors only within the specified operating temperature range.
Use inrush current limiters only within the specified voltage and current ranges.
Environmental conditions must not harm the thermistors. Use thermistors only in normal
atmospheric conditions.
Contact of NTC thermistors with any liquids and solvents should be prevented. It must be
ensured that no water enters the NTC thermistor (e.g. through plug terminals). For
measurement purposes (checking the specified resistance vs. temperature), the component
must not be immersed in water but in suitable liquids (e.g. Galden).
In case of exposure of the NTC thermistors to water, electrolytes or other aggressive media,
these media can penetrate the coating and reach the surface of the ceramic. Low-ohmic or
high-ohmic behavior may occur due to the formation of an electrolyte with metals (silver/lead/tin
from metallization or solder). Low-ohmic behavior is caused by electrochemical migration,
high-ohmic behavior by dissolving of the electrode. Ineither case, the functionality of the NTC
thermistorscannot be assured.
Be sure to provide an appropriate fail-safe function to prevent secondary product damage
caused by malfunction (e.g. use a metal oxide varistor for limitation of overvoltage condition).
Please read Cautions and warnings and
Important notes at the end of this document.
Page 11 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Symbols and terms
Symbol
English
German
Ctest
Cth
Test capacitance
Heat capacitance
Prüfkapazität (elektrisch)
Wärmekapazität
I
Imax
Current
Maximum current within stated
temperature range
NTC current
Rated current
Strom
Maximalstrom im angegebenen
Temperaturbereich
Heißleiter-Strom
Nennstrom
P25
Pdiss
Pel
Pmax
Maximum power at 25 °C
Power dissipation
Electrical power
Maximum power within stated
temperature range
Maximale Leistung bei 25 °C
Verlustleistung
Elektrische Leistung
Maximale Leistung im
angegebenenTemperaturbereich
RR
∆RR/RR
RT
Rated resistance
Resistance tolerance
Resistance at temperature T
(e.g. R25 = resistance at 25 °C)
Nennwiderstand
Widerstandstoleranz
Widerstand bei Temperatur T
(z.B. R25 = Widerstand bei 25 °C)
T
t
TA
ta
Tmax
Temperature
Time
Ambient temperature
Thermal threshold time
Upper category temperature
Temperatur
Zeit
Umgebungstemperatur
Thermische Ansprechzeit
Obere Grenztemperatur
(Kategorietemperatur)
Untere Grenztemperatur
(Kategorietemperatur)
INTC
IR
Tmin
Lower category temperature
TR
Rated temperature
V
Vload
VNTC
Voltage
Spannung
Load voltage
Ladespannung
Voltage drop across an NTC thermistor Spannungsabfall am Heißleiter
α
Temperature coefficient
Temperaturkoeffizient
∆
Tolerance, change
Toleranz, Änderung
δth
Dissipation factor
Wärmeleitwert
τc
Thermal cooling time constant
Thermische Abkühlzeitkonstante
Please read Cautions and warnings and
Important notes at the end of this document.
Nenntemperatur
Page 12 of 14
Inrush current limiters
B57235S0***M0**
ICLs
S235
Abbreviations / Notes
Symbol
English
*
To be replaced by a number in ordering Platzhalter für Zahl im Bestellnummerncodes, type designations etc.
code oder für die Typenbezeichnung.
+
To be replaced by a letter.
Platzhalter für einen Buchstaben.
All dimensions are given in mm.
Alle Maße sind in mm angegeben.
The commas used in numerical values
denote decimal points.
Verwendete Kommas in Zahlenwerten
bezeichnen Dezimalpunkte.
Please read Cautions and warnings and
Important notes at the end of this document.
German
Page 13 of 14
Important notes
The following applies to all products named in this publication:
1. Some parts of this publication contain statements about the suitability of our products for
certain areas of application. These statements are based on our knowledge of typical requirements that are often placed on our products in the areas of application concerned. We
nevertheless expressly point out that such statements cannot be regarded as binding
statements about the suitability of our products for a particular customer application.
As a rule, EPCOS is either unfamiliar with individual customer applications or less familiar
with them than the customers themselves. For these reasons, it is always ultimately incumbent on the customer to check and decide whether an EPCOS product with the properties described in the product specification is suitable for use in a particular customer application.
2. We also point out that in individual cases, a malfunction of electronic components or
failure before the end of their usual service life cannot be completely ruled out in the
current state of the art, even if they are operated as specified. In customer applications
requiring a very high level of operational safety and especially in customer applications in
which the malfunction or failure of an electronic component could endanger human life or
health (e.g. in accident prevention or lifesaving systems), it must therefore be ensured by
means of suitable design of the customer application or other action taken by the customer
(e.g. installation of protective circuitry or redundancy) that no injury or damage is sustained by
third parties in the event of malfunction or failure of an electronic component.
3. The warnings, cautions and product-specific notes must be observed.
4. In order to satisfy certain technical requirements, some of the products described in this
publication may contain substances subject to restrictions in certain jurisdictions (e.g.
because they are classed as hazardous). Useful information on this will be found in our Material Data Sheets on the Internet (www.epcos.com/material). Should you have any more detailed questions, please contact our sales offices.
5. We constantly strive to improve our products. Consequently, the products described in this
publication may change from time to time. The same is true of the corresponding product
specifications. Please check therefore to what extent product descriptions and specifications
contained in this publication are still applicable before or when you place an order. We also
reserve the right to discontinue production and delivery of products. Consequently, we
cannot guarantee that all products named in this publication will always be available. The
aforementioned does not apply in the case of individual agreements deviating from the foregoing for customer-specific products.
6. Unless otherwise agreed in individual contracts, all orders are subject to the current version of the "General Terms of Delivery for Products and Services in the Electrical Industry" published by the German Electrical and Electronics Industry Association
(ZVEI).
7. The trade names EPCOS, BAOKE, Alu-X, CeraDiode, CSMP, CSSP, CTVS, DeltaCap,
DigiSiMic, DSSP, FormFit, MiniBlue, MiniCell, MKD, MKK, MLSC, MotorCap, PCC,
PhaseCap, PhaseCube, PhaseMod, PhiCap, SIFERRIT, SIFI, SIKOREL, SilverCap,
SIMDAD, SiMic, SIMID, SineFormer, SIOV, SIP5D, SIP5K, ThermoFuse, WindCap are trademarks registered or pending in Europe and in other countries. Further information will be
found on the Internet at www.epcos.com/trademarks.
Page 14 of 14