NTC thermistors for
temperature measurement
Glass-encapsulated sensors,
standard type
Series/Type: B57540G1
Date: January 2018
© EPCOS AG 2018. Reproduction, publication and dissemination of this publication, enclosures hereto and the
information contained therein without EPCOS' prior express consent is prohibited.
EPCOS AG is a TDK Group Company.
Applications
Temperature measurement
Features
Glass-encapsulated, heat-resistive and
highly stable
For temperature measurement up to 250 °C
Very short response time
Small dimensions
Leads: dumet wires (copper-clad FeNi)
Options
Leads: nickel-plated dumet wires
Alternative dimensions available on request
Delivery mode
Bulk
Dimensional drawing
Dimensions in mm
Approx. weight 20 mg
General technical data
Climatic category (IEC 60068-1) 55/250/56
Max. power (at 25 °C) P25 18 mW
Resistance tolerance ∆RR/RR±2, ±3 %
Rated temperature TR25 °C
Dissipation factor (in air) δth approx. 0.4 mW/K
Thermal cooling time constant (in air) τcapprox. 3 s
Heat capacity Cth approx. 1.3 mJ/K
Electrical specification and ordering codes
R25
ΩNo. of R/T
characteristic
B25/85
K
B0/100
K
B25/100
K
Ordering code
+ = Resistance tolerance
G = ±2%
H = ±3%
5 k 8324 3483 3455 3497 ±1% B57540G1502+000
10 k 8307 3478 3450 3492 ±1% B57540G1103+000
10 k 7003 3612 3586 3625 ±1% B57540G1103+005
50 k 8342 3991 3967 4006 ±1% B57540G1503+000
100 k 8304 4072 4036 4092 ±1% B57540G1104+000
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 2 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Reliability data
Test Standard Test conditions ∆R25/R25
(typical)
Remarks
Storage in
dry heat
IEC
60068-2-2
Storage at upper
category temperature
T: 250 °C
t: 1000 h
< 3% No visible
damage
Storage in damp
heat, steady state
IEC
60068-2-67
Temperature of air: 85 °C
Relative humidity of air: 85%
Duration: 1000 h
< 2% No visible
damage
Rapid temperature
cycling
IEC
60068-2-14
Lower test temperature: 55 °C
Upper test temperature: 200 °C
Number of cycles: 1000
< 2% No visible
damage
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 3 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Reliability data according to AEC-Q200, Rev. D
Test Standard Test conditions ∆R25/R25
(typical)
Remarks
High temperature
exposure (storage)
MIL-STD-202,
method 108
Storage at T = +125 °C
t = 1000 h
< 2% No visible
damage
Operational life MIL-STD-202,
method 108
1000 h / +125 °C
Test voltage max. 0.3 V DC on
NTC1)
< 2% No visible
damage
Temperature
cycling
JESD 22,
method JA-104
Lower test temperature: 55 °C
Upper test temperature: 125 °C
1000 cycles
Dwell time: max. 30 min at each
temperature
Transition time in air: max. 1 min
< 2% No visible
damage
Terminal strength
(leaded)
MIL-STD-202,
method 211
Test leaded device integrity
Condition A: 2.27 N2)
< 1% No visible
damage
Mechanical shock MIL-STD-202,
method 213,
condition C
Acceleration: 40 g2)
Pulse duration: 6 ms
Number of bumps: 3, each
direction
< 1% No visible
damage
Vibration MIL-STD-202,
method 204
Acceleration: 5 g
t = 20 min
12 cycles in each of 3 directions
Frequency range: 10 ... 2000 Hz
< 1% No visible
damage
1) Self heating of the NTC thermistor must not exceed 0.2 K, steady state. Test conditions deviating from AEC-Q200, Rev. D.
2) Deviating from AEC-Q200, Rev. D.
Note
Contact of NTC thermistors with any liquids and solvents shall be prevented. It must be
ensured that no water enters the NTC thermistors (e.g. through plug terminals).
Avoid dewing and condensation unless thermistor is specified for these conditions.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 4 of 23Please read Cautions and warnings and
Important notes at the end of this document.
R/T characteristics
R/T No. 7003 8304
T (°C) B25/100 = 3625 K B25/100 = 4092 K
RT/R25 α(%/K) RT/R25 α(%/K)
55.0 63.225 6.7 100.11 7.4
50.0 45.46 6.5 69.56 7.2
45.0 33.07 6.3 48.945 6.9
40.0 24.324 6.0 34.853 6.7
35.0 18.081 5.8 25.102 6.5
30.0 13.575 5.6 18.275 6.2
25.0 10.29 5.4 13.443 6.0
20.0 7.8716 5.3 9.9853 5.9
15.0 6.0739 5.1 7.4867 5.7
10.0 4.7258 4.9 5.6636 5.5
5.0 3.7062 4.8 4.3212 5.3
0.0 2.9287 4.6 3.324 5.2
5.0 2.3311 4.5 2.5769 5.0
10.0 1.8684 4.4 2.0127 4.9
15.0 1.5075 4.2 1.5834 4.7
20.0 1.224 4.1 1.2542 4.6
25.0 1.0000 4.0 1.0000 4.5
30.0 0.82176 3.9 0.80239 4.3
35.0 0.67909 3.8 0.64776 4.2
40.0 0.56422 3.7 0.52598 4.1
45.0 0.47122 3.6 0.4295 4.0
50.0 0.3955 3.5 0.35262 3.9
55.0 0.33355 3.4 0.291 3.8
60.0 0.2826 3.3 0.24136 3.7
65.0 0.24049 3.2 0.20114 3.6
70.0 0.20553 3.1 0.16841 3.5
75.0 0.17637 3.0 0.14164 3.4
80.0 0.15195 2.9 0.11963 3.3
85.0 0.13141 2.9 0.10147 3.3
90.0 0.11406 2.8 0.086407 3.2
95.0 0.099352 2.7 0.073867 3.1
100.0 0.086837 2.7 0.063383 3.0
105.0 0.076149 2.6 0.054584 3.0
110.0 0.066989 2.5 0.04717 2.9
115.0 0.059112 2.5 0.040901 2.8
120.0 0.052316 2.4 0.035581 2.8
125.0 0.046433 2.4 0.03105 2.7
130.0 0.041327 2.3 0.027179 2.6
135.0 0.03688 2.3 0.023861 2.6
140.0 0.032998 2.2 0.021008 2.5
145.0 0.029598 2.2 0.018548 2.5
150.0 0.026612 2.1 0.016419 2.4
155.0 0.023984 2.1 0.014573 2.4
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 5 of 23Please read Cautions and warnings and
Important notes at the end of this document.
R/T No. 7003 8304
T (°C) B25/100 = 3625 K B25/100 = 4092 K
RT/R25 α(%/K) RT/R25 α(%/K)
160.0 0.021665 2.0 0.012967 2.3
165.0 0.019613 2.0 0.011566 2.3
170.0 0.017793 1.9 0.010341 2.2
175.0 0.016176 1.9 0.0092664 2.2
180.0 0.014735 1.8 0.0083224 2.1
185.0 0.013448 1.8 0.0074907 2.1
190.0 0.012297 1.8 0.0067564 2.0
195.0 0.011265 1.7 0.0061064 2.0
200.0 0.010338 1.7 0.0055299 2.0
205.0 0.009504 1.7 0.0050175 1.9
210.0 0.0087516 1.6 0.0045611 1.9
215.0 0.0080718 1.6 0.0041537 1.9
220.0 0.0074567 1.6 0.0037895 1.8
225.0 0.0068989 1.5 0.0034631 1.8
230.0 0.0063925 1.5 0.0031701 1.8
235.0 0.0059318 1.5 0.0029067 1.7
240.0 0.005512 1.5 0.0026693 1.7
245.0 0.005129 1.4 0.0024551 1.7
250.0 0.004779 1.4 0.0022615 1.6
255.0 0.0044586 1.4 0.0020862 1.6
260.0 0.004165 1.4 0.0019273 1.6
265.0 0.0038955 1.3 0.0017829 1.5
270.0 0.0036478 1.3 0.0016516 1.5
275.0 0.0034199 1.3 0.0015319 1.5
280.0 0.0032098 1.3 0.0014228 1.5
285.0 0.003016 1.2 0.0013231 1.4
290.0 0.002837 1.2 0.0012319 1.4
295.0 0.0026714 1.2 0.0011483 1.4
300.0 0.002518 1.2 0.0010716 1.4
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 6 of 23Please read Cautions and warnings and
Important notes at the end of this document.
R/T characteristics
R/T No. 8307 8324 8342
T (°C) B25/100 = 3492 K B25/100 = 3497 K B25/100 = 4006 K
RT/R25 α(%/K) RT/R25 α(%/K) RT/R25 α(%/K)
55.0 52.624 6.4 53.720 6.5 100.56 7.5
50.0 38.452 6.2 39.080 6.2 69.453 7.3
45.0 28.401 6.0 28.768 6.0 48.647 7.0
40.0 21.194 5.8 21.412 5.8 34.525 6.7
35.0 15.972 5.6 16.104 5.6 24.808 6.5
30.0 12.149 5.4 12.231 5.4 18.036 6.3
25.0 9.3246 5.2 9.3758 5.2 13.258 6.1
20.0 7.2181 5.0 7.2507 5.1 9.8478 5.8
15.0 5.6332 4.9 5.6542 4.9 7.3874 5.7
10.0 4.4308 4.7 4.4444 4.7 5.5937 5.5
5.0 3.5112 4.6 3.5200 4.6 4.2733 5.3
0.0 2.8024 4.4 2.8080 4.5 3.2922 5.1
5.0 2.252 4.3 2.2555 4.3 2.5567 5.0
10.0 1.8216 4.2 1.8236 4.2 2.0007 4.8
15.0 1.4827 4.1 1.4838 4.1 1.577 4.7
20.0 1.2142 3.9 1.2146 3.9 1.2516 4.5
25.0 1.0000 3.8 1.0000 3.8 1.0000 4.4
30.0 0.82818 3.7 0.82789 3.7 0.80501 4.3
35.0 0.68954 3.6 0.68906 3.6 0.65207 4.2
40.0 0.57703 3.5 0.57644 3.5 0.53135 4.0
45.0 0.48525 3.4 0.48461 3.4 0.43546 3.9
50.0 0.41 3.3 0.40933 3.3 0.35884 3.8
55.0 0.34798 3.2 0.34732 3.2 0.29726 3.7
60.0 0.29663 3.2 0.29599 3.2 0.24751 3.6
65.0 0.25392 3.1 0.25331 3.1 0.20709 3.5
70.0 0.21824 3.0 0.21767 3.0 0.17408 3.4
75.0 0.1883 2.9 0.18777 2.9 0.147 3.3
80.0 0.16307 2.8 0.16259 2.8 0.12468 3.3
85.0 0.14174 2.8 0.14130 2.8 0.10618 3.2
90.0 0.12362 2.7 0.12323 2.7 0.0908 3.1
95.0 0.10818 2.6 0.10783 2.6 0.077949 3.0
100.0 0.094973 2.6 0.094663 2.6 0.067168 2.9
105.0 0.08364 2.5 0.083368 2.5 0.058088 2.9
110.0 0.073881 2.5 0.073645 2.5 0.050412 2.8
115.0 0.06545 2.4 0.065247 2.4 0.043898 2.7
120.0 0.058144 2.3 0.057972 2.3 0.038351 2.7
125.0 0.051794 2.3 0.051649 2.3 0.033611 2.6
130.0 0.046259 2.2 0.046139 2.2 0.029546 2.5
135.0 0.04142 2.2 0.041323 2.2 0.02605 2.5
140.0 0.037179 2.1 0.037102 2.1 0.023033 2.4
145.0 0.033451 2.1 0.033393 2.1 0.020421 2.4
150.0 0.030166 2.0 0.030125 2.0 0.018154 2.3
155.0 0.027264 2.0 0.027238 2.0 0.016181 2.3
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 7 of 23Please read Cautions and warnings and
Important notes at the end of this document.
R/T No. 8307 8324 8342
T (°C) B25/100 = 3492 K B25/100 = 3497 K B25/100 = 4006 K
RT/R25 α(%/K) RT/R25 α(%/K) RT/R25 α(%/K)
160.0 0.024694 2.0 0.024669 1.9 0.014458 2.2
165.0 0.022414 1.9 0.022398 1.9 0.01295 2.2
170.0 0.020385 1.9 0.020383 1.9 0.011626 2.1
175.0 0.018577 1.8 0.018589 1.8 0.010462 2.1
180.0 0.016961 1.8 0.016987 1.8 0.0094347 2.0
185.0 0.015514 1.8 0.015552 1.7 0.0085267 2.0
190.0 0.014216 1.7 0.014263 1.7 0.0077222 2.0
195.0 0.013049 1.7 0.013104 1.7 0.0070076 1.9
200.0 0.011999 1.7 0.012060 1.6 0.0063716 1.9
205.0 0.011051 1.6 0.011117 1.6 0.0058044 1.8
210.0 0.010194 1.6 0.010264 1.6 0.0052974 1.8
215.0 0.0094181 1.6 0.0094930 1.5 0.0048434 1.8
220.0 0.0087144 1.5 0.0087939 1.5 0.004436 1.7
225.0 0.0080751 1.5 0.0081599 1.5 0.0040697 1.7
230.0 0.0074933 1.5 0.0075842 1.4 0.0037398 1.7
235.0 0.0069631 1.5 0.0070611 1.4 0.0034422 1.6
240.0 0.0064791 1.4 0.0065853 1.4 0.0031732 1.6
245.0 0.0060366 1.4 0.0061522 1.3 0.0029296 1.6
250.0 0.0056316 1.4 0.0057577 1.3 0.0027087 1.6
255.0 0.0052602 1.4
260.0 0.0049193 1.3
265.0 0.0046059 1.3
270.0 0.0043173 1.3
275.0 0.0040514 1.3
280.0 0.003806 1.2
285.0 0.0035793 1.2
290.0 0.0033696 1.2
295.0 0.0031753 1.2
300.0 0.0029952 1.2
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 8 of 23Please read Cautions and warnings and
Important notes at the end of this document.
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.
1.1.1 Wave soldering
Temperature characteristic at component terminal with dual wave soldering
1.2 Leadless NTC thermistors
In case of NTC thermistors without leads, soldering is restricted to devices which are provided
with a solderable metallization. The temperature shock caused by the application of hot solder
may produce fine cracks in the ceramic, resulting in changes in resistance.
To prevent leaching of the metallization, solder with silver additives or with a low tin content
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 9 of 23Please read Cautions and warnings and
Important notes at the end of this document.
should be used. In addition, soldering methods should be employed which permit short soldering
times.
1.3 SMD NTC thermistors
SMD NTC thermistors can be provided with a nickel barrier termination or on special request with
silver-palladium termination. The use of no-clean solder products is recommended. In any case
mild, non-activated fluxes should be used. Flux residues after soldering should be minimized.
SMD NTCs with AgPd termination are not approved for lead-free soldering.
Nickel barrier termination
Figure 1
SMD NTC thermistors, structure of nickel
barrier termination
The nickel barrier layer of the silver/nickel/tin termination (see figure 1) prevents leaching of the
silver base metallization layer. This allows great flexibility in the selection of soldering parameters.
The tin prevents the nickel layer from oxidizing and thus ensures better wetting by the solder. The
nickel barrier termination is tested for all commonly-used soldering methods according to IEC
60068-2-58. Insufficient preheating may cause ceramic cracks. Rapid cooling by dipping in sol-
vent is not recommended.
The following test and process conditions apply for nickel barrier termination.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 10 of 23Please read Cautions and warnings and
Important notes at the end of this document.
1.3.1 Solderability (test to IEC 60068-2-58)
Preconditioning: Immersion into flux F-SW 32.
Evaluation criterion: Wetting of soldering areas ≥95%.
Solder Bath temperature (°C) Dwell time (s)
SnPb 60/40 215 ±3 3 ±0.3
SnAg (3.0 ... 4.0), Cu (0.5 ... 0.9) 245 ±3 3 ±0.3
1.3.2 Resistance to soldering heat (test to IEC 60068-2-58)
Preconditioning: Immersion into flux F-SW 32.
Evaluation criterion: Leaching of side edges ≤1/3.
Solder Bath temperature (°C) Dwell time (s)
SnPb 60/40 260 ±5 10 ±1
SnAg (3.0 ... 4.0), Cu (0.5 ... 0.9) 260 ±5 10 ±1
1.3.3 Reflow soldering
Temperature ranges for reflow soldering acc. to IEC 60068-2-58 recommendations.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 11 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Profile feature Sn-Pb eutectic assembly Pb-free assembly
Preheat and soak
- Temperature min Tsmin 100 °C 150 °C
- Temperature max Tsmax 150 °C 200 °C
- Time tsmin to tsmax 60 ... 120 s 60 ... 120 s
Average ramp-up rate Tsmax to Tp3°C/ s max. 3 °C/ s max.
Liquidous temperature TL183 °C 217 °C
Time at liquidous tL40 ... 150 s 40 ... 150 s
Peak package body temperature Tp215 °C ... 260 °C1) 235 °C ... 260 °C
Time above (TP5°C) tp10 ... 40 s 10 ... 40 s
Average ramp-down rate Tpto Tsmax 6°C/ s max. 6 °C/ s max.
Time 25 °C to peak temperature max. 8 minutes max. 8 minutes
1) Depending on package thickness.
Notes: All temperatures refer to topside of the package, measured on the package body
surface.
Number of reflow cycles: 3
Iron soldering should be avoided, hot air methods are recommended for repair
purposes.
Solder joint profiles for silver/nickel/tin terminations
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 12 of 23Please read Cautions and warnings and
Important notes at the end of this document.
1.3.4 Recommended geometry of solder pads
Recommended maximum dimensions (mm)
Case size
inch/mm
ABC
0402/1005 0.6 0.6 1.7
0603/1608 1.0 1.0 3.0
0805/2012 1.3 1.2 3.4
1206/3216 1.8 1.2 4.5
2 Conductive adhesion
An alternative to soldering for silver-palladium terminated components is the gluing of thermistors
with conductive adhesives. The benefit of this method is that it involves no thermal stress. The
adhesives used must be chemically inert.
3 Clamp contacting
Pressure contacting by means of clamps is particularly suitable for applications involving frequent
switching and high turn-on powers.
4 Robustness of terminations (leaded types)
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 feed-
throughs. During bending, any mechanical stress at the outlet of the leads must be removed. The
bending radius should be at least 0.75 mm.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 13 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Tensile strength: Test Ua1:
Value of applied force for Ua1 test:
Diameter (d) of
corresponding round leads
Force with tolerance of ±10%
∅≤0.25 mm 1.0 N
0.25 < ∅≤0.35 mm 2.5 N
0.35 < ∅≤0.50 mm 5.0 N
0.50 < ∅≤0.80 mm 10.0 N
Bending strength: Test Ub:
Two 90°-bends in opposite directions
Value of applied force for Ub test:
Diameter (d) of
corresponding round leads
Force with tolerance of ±10%
∅≤0.25 mm 0.5 N
0.25 < ∅≤0.35 mm 1.25 N
0.35 < ∅≤0.50 mm 2.5 N
0.50 < ∅≤0.80 mm 5 N
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).
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 +4 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.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 14 of 23Please read Cautions and warnings and
Important notes at the end of this document.
5 Sealing and potting
Sealing or potting processes can affect the reliability of the component.
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.
As thermistors are temperature sensitive components it should be considered that molding can af-
fect the thermal surrounding and may influence e.g. the response time.
Extensive testing is encouraged in order to determine whether overmolding or potting influences
the functionality and/ or reliability of the component.
6 Cleaning
Cleaning processes can affect the reliability of the component.
If cleaning is necessary, mild cleaning agents are recommended. Cleaning agents based on wa-
ter are not allowed. Washing processes may damage the product due to the possible static or
cyclic mechanical loads (e.g. ultrasonic cleaning). They may cause cracks which might lead to re-
duced reliability and/ or lifetime.
7 Storage
In order to maintain their solderability, thermistors must be stored in a non-corrosive atmosphere.
Humidity, temperature and container materials are critical factors.
Do not store SMDs where they are exposed to heat or direct sunlight. Otherwise, the packing ma-
terial may be deformed or SMDs may stick together, causing problems during mounting. After
opening the factory seals, such as polyvinyl-sealed packages, use the SMDs as soon as possible.
The components should be left in the original packing. Touching the metallization of unsoldered
thermistors may change their soldering properties.
Storage temperature: 25 °Cupto45°C
Relative humidity (without condensation): ≤75% annual mean
<95%, maximum 30 days per annum
Solder the thermistors listed in this data book after shipment from EPCOS within the time speci-
fied:
SMDs with AgPd termination: 6 months
SMDs with nickel barrier termination: 12 months
Leadless components: 12 months
Leaded components: 24 months
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 15 of 23Please read Cautions and warnings and
Important notes at the end of this document.
8 Placement and orientation of SMD NTC thermistors on PCB
a) Component placement
It is recommended that the PC board
should be held by means of some
adequate supporting pins such as
shown left to prevent the SMDs from
being damaged or cracked.
b) Cracks
When placing a component near an
area which is apt to bend or a grid
groove on the PC board, it is advisable
to have both electrodes subjected to
uniform stress, or to position the
component's electrodes at right angles
to the grid groove or bending line (see
c) Component orientation).
c) Component orientation
Choose a mounting position that
minimizes the stress imposed on the
chip during flexing or bending of the
board.
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 16 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Cautions and warnings
General
See "Important notes" on page 2.
Storage
Store thermistors only in original packaging. Do not open the package prior to processing.
Storage conditions in original packaging: storage temperature 25 °C ... +45 °C, relative
humidity ≤75% annual mean, <95% maximum 30 days per annum, dew precipitation is
inadmissible.
Do not store thermistors where they are exposed to heat or direct sunlight. Otherwise, the
packing material may be deformed or components may stick together, causing problems during
mounting.
Avoid contamination of thermistor surface during storage, handling and processing.
Avoid storage of thermistors in harmful environments like corrosive gases (SOx, Cl etc).
Use the components as soon as possible after opening the original packaging.
Solder thermistors within the time specified after shipment from EPCOS.
For leaded components this is 24 months, for SMD components with nickel barrier termination
12 months, for leadless components this is 12 months, for SMD components with AgPd
termination 6 months.
Handling
NTC thermistors must not be dropped. Chip-offs or any other damage must not be caused
during handling of NTCs.
Do not touch components with bare hands. Gloves are recommended.
Avoid contamination of thermistor surface during handling.
Washing processes may damage the product due to the possible static or cyclic mechanical
loads (e.g. ultrasonic cleaning). They may cause cracks to develop on the product and its parts,
which might lead to reduced reliability or lifetime.
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.
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.
Temperature measurement B57540G1
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Important notes at the end of this document.
Mounting
Ensure that no thermo-mechanical stress occurs due to production processes (curing or
overmolding processes) when thermistors are sealed, potted or overmolded or during their
subsequent operation. The maximum temperature of the thermistor must not be exceeded.
Ensure that the materials used (sealing/potting compound and plastic material) are chemically
neutral.
Electrodes/contacts must not be scratched or damaged before/during/after the mounting
process.
Contacts and housing used for assembly with the thermistor must be clean before mounting.
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 the temperature.
Avoid contamination of the thermistor surface during processing.
The connections of sensors (e.g. cable end, wire end, plug terminal) may only be exposed to
an environment with normal atmospheric conditions.
Tensile forces on cables or leads must be avoided during mounting and operation.
Bending or twisting of cables or leads directly on the thermistor body is not permissible.
Avoid using chemical substances as mounting aids. It must be ensured that no water or other
liquids enter the NTC thermistors (e.g. through plug terminals). In particular, water based
substances (e.g. soap suds) must not be used as mounting aids for sensors.
The use of no-clean solder products is recommended. In any case mild, non-activated fluxes
should be used. Flux residues after soldering should be minimized.
Operation
Use thermistors only within the specified operating temperature range.
Use thermistors only within the specified power range.
Environmental conditions must not harm the thermistors. Only use the thermistors under
normal atmospheric conditions or within the specified conditions.
Contact of NTC thermistors with any liquids and solvents shall be prevented. It must be
ensured that no water enters the NTC thermistors (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. perfluoropolyethers such as Galden).
Avoid dewing and condensation unless thermistor is specified for these conditions.
Bending or twisting of cables and/or wires is not permissible during operation of the sensor in
the application.
Be sure to provide an appropriate fail-safe function to prevent secondary product damage
caused by malfunction.
This listing does not claim to be complete, but merely reflects the experience of EPCOS AG.
Display of ordering codes for EPCOS products
The ordering code for one and the same EPCOS product can be represented differently in data
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 18 of 23Please read Cautions and warnings and
Important notes at the end of this document.
sheets, data books, other publications, on the EPCOS website, or in order-related documents
such as shipping notes, order confirmations and product labels. The varying representations of
the ordering codes are due to different processes employed and do not affect the
specifications of the respective products. Detailed information can be found on the Internet
under www.epcos.com/orderingcodes
Temperature measurement B57540G1
Glass-encapsulated sensors G1540
Page 19 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Symbols and terms
Symbol English German
A Area Fläche
AWG American Wire Gauge Amerikanische Norm für Drahtquerschnitte
B B value B-Wert
B25/100 B value determined by resistance
measurement at 25 °C and 100 °C
B-Wert, ermittelt durch Widerstands-
messungen bei 25 °C und 100 °C
Cth Heat capacitance Wärmekapazität
I Current Strom
N Number (integer) Anzahl (ganzzahliger Wert)
P25 Maximum power at 25 °C Maximale Leistung bei 25 °C
Pdiss Power dissipation Verlustleistung
Pel Electrical power Elektrische Leistung
Pmax Maximum power within stated
temperature range
Maximale Leistung im
angegebenenTemperaturbereich
∆RB/RBResistance tolerance caused by
spread of B value
Widerstandstoleranz, die durch die
Streuung des B-Wertes verursacht wird
Rins Insulation resistance Isolationswiderstand
RPParallel resistance Parallelwiderstand
RRRated resistance Nennwiderstand
∆RR/RRResistance tolerance Widerstandstoleranz
RSSeries resistance Serienwiderstand
RTResistance at temperature T
(e.g. R25 = resistance at 25 °C)
Widerstand bei Temperatur T
(z.B. R25 = Widerstand bei 25 °C)
T Temperature Temperatur
∆T Temperature tolerance Temperaturtoleranz
t Time Zeit
TAAmbient temperature Umgebungstemperatur
Tmax Upper category temperature Obere Grenztemperatur
(Kategorietemperatur)
Tmin Lower category temperature Untere Grenztemperatur
(Kategorietemperatur)
Top Operating temperature Betriebstemperatur
TRRated temperature Nenntemperatur
Tsurf Surface temperature Oberflächentemperatur
V Voltage Spannung
Vins Insulation test voltage Isolationsprüfspannung
Vop Operating voltage Betriebsspannung
Vtest Test voltage Prüfspannung
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Glass-encapsulated sensors G1540
Page 20 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Symbol English German
αTemperature coefficient Temperaturkoeffizient
∆Tolerance, change Toleranz, Änderung
δth Dissipation factor Wärmeleitwert
τcThermal cooling time constant Thermische Abkühlzeitkonstante
τaThermal time constant Thermische Zeitkonstante
Abbreviations / Notes
Symbol English German
Surface-mounted devices Oberflächenmontierbares Bauelement
* To be replaced by a number in ordering
codes, type designations etc.
Platzhalter für Zahl im Bestellnummern-
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.
Temperature measurement B57540G1
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Page 21 of 23Please read Cautions and warnings and
Important notes at the end of this document.
Page 22 of 23
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 we are 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 a 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 life-saving 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.tdk-electronics.tdk.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 our General Terms
and Conditions of Supply.
7. Our manufacturing sites serving the automotive business apply the IATF 16949 standard.
The IATF certifications confirm our compliance with requirements regarding the quality
management system in the automotive industry. Referring to customer requirements and
customer specific requirements (“CSR”) TDK always has and will continue to have the policy of
respecting individual agreements. Even if IATF 16949 may appear to support the acceptance of
unilateral requirements, we hereby like to emphasize that only requirements mutually agreed
upon can and will be implemented in our Quality Management System. For clarification
purposes we like to point out that obligations from IATF 16949 shall only become legally binding if
individually agreed upon.
Page 23 of 23
Important notes
8. The trade names EPCOS, CeraCharge, CeraDiode, CeraLink, CeraPad, CeraPlas, CSMP, CTVS,
DeltaCap, DigiSiMic, ExoCore, FilterCap, FormFit, LeaXield, MiniBlue, MiniCell, MKD, MKK,
MotorCap, PCC, PhaseCap, PhaseCube, PhaseMod, PhiCap, PowerHap, PQSine, PQvar,
SIFERRIT, SIFI, SIKOREL, SilverCap, SIMDAD, SiMic, SIMID, SineFormer, SIOV, ThermoFuse,
WindCap are trademarks registered or pending in Europe and in other countries. Further
information will be found on the Internet at www.tdk-electronics.tdk.com/trademarks.
Release 2018-10
