EPCOS B59750B0120A070

PTC thermistors as
inrush current limiters
Leaded disks
Series/Type:
B5975*
Date:
November 2009
© EPCOS AG 2009. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS' prior express consent is prohibited.
Inrush current limiters
Leaded disks
Applications
Inrush current limiter (charging resistor) for
smoothing and DC link capacitors
To replace high-power fixed resistors for
capacitor charging
Dimensional drawing
Features
Self-protecting in case of malfunction of
short-circuit relay or internal short circuit of
capacitor
Inrush current limiters are not damaged
when directly connected to Vmax even without
additional current limitation
RoHS-compatible
Dimensions in mm
Type
B750
B751
B752
B753
B754
B755
Delivery mode
Cardboard strips
wmax
12.5
12.5
12.5
12.5
12.5
12.5
hmax
16.5
16.5
16.5
16.5
16.5
16.5
thmax
5.0
7.0
7.0
7.0
7.0
7.0
General technical data
Operating cycles at Vmax
Switching cycles at Vmax
Operating temperature range
Operating temperature range
(charging of capacitor)
(failure mode)
(V = 0)
(V = Vmax)
Nc
Nf
Top
Top
> 50000
> 10
40/+125
20/+85
cycles
cycles
°C
°C
Electrical specifications and ordering codes
Type
Vmax
Vlink,max
RR
∆RR
B750
B751
B752
B753
B754
B755
V AC
260
260
260
440
440
560
V DC
360
360
360
620
620
800
Ω
25
50
80
120
150
500
%
±25
±25
±25
±25
±25
±25
Please read Cautions and warnings and
Important notes at the end of this document.
Tref
(typ.)
°C
115
115
115
115
115
110
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Cth
τth
Ordering code
J/K
1.0
1.4
1.4
1.4
1.4
1.4
s
100
120
120
120
120
120
B59750B0120A070
B59751B0120A070
B59752B0120A070
B59753B0120A070
B59754B0120A070
B59755B0115A070
Inrush current limiters
Leaded disks
Reliability data
Test
Electrical endurance,
cycling
Standard
Electrical endurance,
constant
Damp heat
IEC 60738-1
Rapid change
of temperature
IEC 60738-1
Vibration
IEC 60738-1
Climatic sequence
IEC 60738-1
IEC 60738-1
Please read Cautions and warnings and
Important notes at the end of this document.
Test conditions
Room temperature, Vlink,max
applied energy < Cth (Tref TA)
Number of cycles: 100 000
Storage at Vmax /Top,max (Vmax)
Test duration: 1000 h
Temperature of air: 40 °C
Relative humidity of air: 93%
Duration: 56 days
Test according to IEC 60068-2-78
T1 = Top,min (0 V), T2 = Top,max (0 V)
Number of cycles: 5
Test duration: 30 min
Test according to IEC 60068-2-14, Test Na
Frequency range: 10 to 55 Hz
Displacement amplitude: 0.75 mm
Test duration: 3 × 2 h
Test according to IEC 60068-2-6, Test Fc
Dry heat: T = Top,max (0 V)
Test duration: 16 h
Damp heat first cycle
Cold: T = Top,min (0 V)
Test duration: 2 h
Damp heat 5 cycles
Tests performed according to
IEC 60068-2-30
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∆R25/R25
< 25%
< 25%
< 10%
< 10%
< 5%
< 10%
Inrush current limiters
Leaded disks
Characteristics
Minimum resistance of PTC thermistors
versus applied voltage (pulsed)
Switching time tS versus switching current IS
(measured at 25 °C in still air)
Please read Cautions and warnings and
Important notes at the end of this document.
PTC resistance RPTC versus
PTC temperature TPTC
(measured at low signal voltage)
Residual current in high-ohmic state Ires as
function of applied voltage VPTC, typical
(measured at 25 °C in still air)
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Inrush current limiters
Leaded disks
Calculation of the number of required PTC elements
Number of required PTC elements (connected in parallel) as function of capacitance and charging
voltage of smoothing or DC link capacitor:
N
Number of required PTC thermistors connected in parallel
C
Capacitance of smoothing or DC link capacitor in F
V
Charging voltage of capacitor in V
Cth
Heat capacity in J/K
Tref
Reference temperature of PTC in °C
TA,max
Expected maximum ambient temperature in °C
In case of large N values the resulting resistance of the parallel PTC network might be too low for
effective limitation of the charging current. In this case a combination of series and parallel
connected PTC thermistors can be used.
Please read Cautions and warnings and
Important notes at the end of this document.
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Inrush current limiters
Leaded disks
Cautions and warnings
General
EPCOS thermistors are designed for specific applications and should not be used for purposes
not identified in our specifications, application notes and data books unless otherwise agreed
with EPCOS during the design-in-phase.
Ensure suitability of thermistor through reliability testing during the design-in phase. The thermistors should be evaluated taking into consideration worst-case conditions.
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 environment with effect on function on long-term operation (examples given under operation precautions).
Use thermistor within the following period after delivery:
Through-hole devices (housed and leaded PTCs): 24 months
Motor protection sensors, glass-encapsulated sensors and probe assemblies: 24 months
Telecom pair and quattro protectors (TPP, TQP): 24 months
Leadless PTC thermistors for pressure contacting: 12 months
Leadless PTC thermistors for soldering: 6 months
SMDs in EIA sizes 3225 and 4032, and for PTCs with metal tags: 24 months
SMDs in EIA sizes 0402, 0603, 0805 and 1210: 12 months
Handling
PTCs must not be dropped. Chip-offs must not be caused during handling of PTCs.
Components must not be touched with bare hands. Gloves are recommended.
Avoid contamination of thermistor surface during handling.
Soldering (where applicable)
Use rosin-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.
Standard PTC heaters are not suitable for soldering.
Please read Cautions and warnings and
Important notes at the end of this document.
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Inrush current limiters
Leaded disks
Mounting
Electrode must not be scratched before/during/after the mounting process.
Contacts and housing used for assembly with thermistor have to be clean before mounting. Especially grease or oil must be removed.
When PTC thermistors are encapsulated with sealing material, the precautions given in chapter
"Mounting instructions", "Sealing and potting" must be observed.
When the thermistor is mounted, there must not be any foreign body between the electrode of
the thermistor and the clamping contact.
The minimum force of the clamping contacts pressing against the PTC must be 10 N.
During operation, the thermistor’s surface temperature can be very high. Ensure that adjacent
components are placed at a sufficient distance from the thermistor to allow for proper cooling at
the thermistors.
Ensure that adjacent materials are designed for operation at temperatures comparable to the
surface temperature of thermistor. Be sure that surrounding parts and materials can withstand
this temperature.
Avoid contamination of thermistor surface during processing.
Operation
Use thermistors only within the specified temperature operating range.
Use thermistors only within the specified voltage and current ranges.
Environmental conditions must not harm the thermistors. Use thermistors only in normal atmospheric conditions. Avoid use in deoxidizing gases (chlorine gas, hydrogen sulfide gas, ammonia gas, sulfuric acid gas etc), corrosive agents, humid or salty conditions. Contact with any
liquids and solvents should be prevented.
Be sure to provide an appropriate fail-safe function to prevent secondary product damage
caused by abnormal function (e.g. use VDR for limitation of overvoltage condition).
Please read Cautions and warnings and
Important notes at the end of this document.
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Inrush current limiters
Leaded disks
Symbols and terms
A
Cth
f
I
Imax
IR
IPTC
Ir
Ir,oil
Ir,air
IRMS
IS
ISmax
LCT
N
Nc
Nf
P
P25
Pel
Pdiss
Rmin
RR
∆RR
RP
RPTC
Rref
RS
R25
R25,match
∆R25
T
t
TA
ta
TC
Area
Heat capacity
Frequency
Current
Maximum current
Rated current
PTC current
Residual currrent
Residual currrent in oil (for level sensors)
Residual currrent in air (for level sensors)
Root-mean-square value of current
Switching current
Maximum switching current
Lower category temperature
Number (integer)
Operating cycles at Vmax, charging of capacitor
Switching cycles at Vmax, failure mode
Power
Maximum power at 25 °C
Electrical power
Dissipation power
Minimum resistance
Rated resistance
Tolerance of RR
Parallel resistance
PTC resistance
Reference resistance
Series resistance
Resistance at 25 °C
Resistance matching per reel/ packing unit at 25 °C
Tolerance of R25
Temperature
Time
Ambient temperature
Thermal threshold time
Ferroelectric Curie temperature
Please read Cautions and warnings and
Important notes at the end of this document.
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Inrush current limiters
Leaded disks
tE
TR
Tsense
Top
TPTC
tR
Tref
TRmin
tS
Tsurf
UCT
V or Vel
VRMS
VBD
Vins
Vlink,max
Vmax
Vmax,dyn
Vmeas
Vmeas,max
VR
VPTC
Settling time (for level sensors)
Rated temperature
Sensing temperature
Operating temperature
PTC temperature
Response time
Reference temperature
Temperature at minimum resistance
Switching time
Surface temperature
Upper category temperature
Voltage (with subscript only for distinction from volume)
Root-mean-square value of voltage
Breakdown voltage
Insulation test voltage
Maximum link voltage
Maximum operating voltage
Maximum dynamic (short-time) operating voltage
Measuring voltage
Maximum measuring voltage
Rated voltage
Voltage drop across a PTC thermistor
α
∆
δth
τth
λ
Temperature coefficient
Tolerance, change
Dissipation factor
Thermal cooling time constant
Failure rate
Lead spacing (in mm)
Abbreviations / Notes
Surface-mount devices
* To be replaced by a number in ordering codes, type designations etc.
+ To be replaced by a letter
All dimensions are given in mm.
The commas used in numerical values denote decimal points.
Please read Cautions and warnings and
Important notes at the end of this document.
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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,
DSSP, MiniBlue, MiniCell, MKK, MLSC, MotorCap, PCC, PhaseCap, PhaseCube,
PhaseMod, PhiCap, SIFERRIT, SIFI, SIKOREL, SilverCap, SIMDAD, 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.
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