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IEC 60539-2
Edition 2.0 2019-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
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IEC 60539-2
Edition 2.0 2019-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Directly heated negative temperature coefficient thermistors –
Part 2: Sectional specification – Surface mount negative temperature coefficient
thermistors
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.040.30 ISBN 978-2-8322-7199-5
– 2 – IEC 60539-2:2019 RLV IEC 2019
CONTENTS
FOREWORD . 5
1 General .
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Information to be given in a detail specification . 8
4.1 General . 8
4.2 Outline drawing and dimensions . 8
4.3 Mounting . 8
4.4 Ratings and characteristics . 8
4.4.1 Particular characteristics . 8
4.4.2 Marking . 8
Terminology .
5 Preferred ratings and characteristics . 9
5.1 Tolerances on rated zero-power resistance . 9
5.2 Climatic categories . 9
6 Quality assessment procedures . 9
Primary stage of manufacture .
Structurally similar components .
Qualification approval procedures .
The manufacturer shall comply with 3.4 of IEC 60539-1. .
Quality conformance inspection .
Qualification approval on the basis of the fixed sample size procedure .
Quality conformance inspection .
Formation of inspection lots .
Test schedule .
Delayed delivery .
Assessment level .
7 Test and measurement procedures . 13
7.1 Mounting . 13
7.2 Drying and recovery . 13
7.2.1 Drying . 13
7.2.2 Recovery . 13
7.3 Visual examination and check of dimensions . 13
7.3.1 Visual examination . 13
7.3.2 Requirements . 14
7.3.3 Marking . 15
7.3.4 Dimensions . 16
7.4 Electrical tests . 16
7.4.1 Zero-power resistance . 16
7.4.2 B-value or resistance ratio . 16
7.4.3 Resistance/temperature characteristic . 16
7.5 Thermal tests . 17
7.5.1 Dissipation factor (δ) . 17
7.5.2 Thermal time constant by cooling after self-heating (τ ) . 17
c
7.6 Resistance to soldering heat . 17
7.6.1 General . 17
7.6.2 Initial measurement . 17
7.6.3 Test conditions . 17
7.6.4 Recovery . 18
7.6.5 Final inspection, measurements and requirements. 18
7.7 Solderability . 18
7.7.1 General . 18
7.7.2 Test conditions . 18
7.7.3 Recovery . 19
7.7.4 Final inspection, measurements and requirements. 19
7.8 Rapid change of temperature . 19
7.9 Thermal shock . 19
Climatic sequence.
Initial measurements .
Dry heat .
Damp heat (cyclic), first cycle .
Cold.
Damp heat (cyclic), remaining cycles .
Final measurements .
7.10 Damp heat, steady state . 21
7.11 Endurance . 21
7.11.1 Endurance at T and P . 21
3 max
7.11.2 Endurance at upper category temperature . 22
7.12 Shear (adhesion) test . 22
7.13 Substrate bending test . 22
7.14 Component solvent resistance . 22
7.15 Solvent resistance of marking . 22
Annex A (normative) Guide for the specification and coding of dimensions of surface
mount negative temperature coefficient thermistors . 23
Annex B (normative) Quality assessment procedure . 25
B.1 Primary stage of manufacture . 25
B.2 Structurally similar components . 25
B.3 Qualification approval procedures . 25
B.4 Quality conformance inspection . 25
B.4.1 General . 25
B.4.2 Qualification approval on the basis of the fixed sample size procedure . 25
B.5 Quality conformance inspection . 27
B.5.1 Formation of inspection lots . 27
B.5.2 Test schedule . 28
B.5.3 Delayed delivery . 28
B.5.4 Assessment level . 28
Figure 1 – Fault: fissure or defect . 14
Figure 2 – Fault: crack . 14
Figure 3 – Separation or delamination . 14
Figure 4 – Exposed electrodes . 15
Figure 5 – Principal faces . 15
– 4 – IEC 60539-2:2019 RLV IEC 2019
Figure 6 – Principal terminations – Gull wing . 16
Figure 7 – Principal terminations – Round termination . 16
Figure A.1 – Dimensioni
...