IEC 60393-6:2003

INTERNATIONAL IEC
STANDARD
60393-6
First edition
2003-05
Potentiometers for use
in electronic equipment –
Part 6:
Sectional specification:
Surface mount preset potentiometers
Reference number
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INTERNATIONAL IEC
STANDARD
60393-6
First edition
2003-05
Potentiometers for use
in electronic equipment –
Part 6:
Sectional specification:
Surface mount preset potentiometers
 IEC 2003  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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PRICE CODE
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U
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 60393-6  IEC:2003(E)
CONTENTS
FOREWORD . 3
1 General . 4
1.1 Scope . 4
1.2 Object. 4
1.3 Normative references . 4
1.4 Information to be given in a Detail Specification. 5
2 Preferred ratings, characteristics and test severities . 9
2.1 Preferred characteristics. 9
2.2 Preferred values of ratings.14
2.3 Preferred test severities.16
3 Quality assessment procedures .17
3.1 Structurally similar components .17
3.2 Qualification approval .17
3.3 Quality conformance inspection .25
3.4 Delayed delivery.26
Figure 1 – Suitable substrate for mechanical and electrical tests (may not be suitable
for impedance measurements) . 7
Figure 2 – Suitable substrate for electrical tests. 8
Figure 3 – Rated dissipation curve .15
Figure 4 – Rated dissipation curve with larger area of operation .15
Table 1 – Temperature coefficients and temperature characteristics of resistance.10
Table 2 – Limits for change in resistance and output ratio .11
Table 3 – Fixed sample size test schedule for qualification approval – Assessment
level E.19
Table 4 – Assessment level corresponding to inspection subgroup.25
Table 5 – Assessment level corresponding to inspection subgroup.26

60393-6  IEC:2003(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POTENTIOMETERS FOR USE IN ELECTRONIC EQUIPMENT –
Part 6: Sectional specification:
Surface mount preset potentiometers
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical Specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60393-6 has been prepared by IEC technical committee 40:
Capacitors and resistors for electronic equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
40/1288/FDIS 40/1324/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This Sectional Specification is to be used in conjunction with IEC 60393-1:1989.
The committee has decided that the contents of this publication will remain unchanged
until 2008. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended
A bilingual version of this publication may be issued at a later date.

– 4 – 60393-6  IEC:2003(E)
POTENTIOMETERS FOR USE IN ELECTRONIC EQUIPMENT –
Part 6: Sectional specification:
Surface mount preset potentiometers
1 General
1.1 Scope
This International Standard is applicable to surface mount preset potentiometers for use in
electronic equipment.
1.2 Object
The object of this standard is to prescribe preferred ratings and characteristics and to
select the appropriate quality assessment procedures, tests and measuring methods from
IEC 60393-1 and to give general performance requirements for this type of potentiometer.
Test severities and requirements prescribed in Detail Specifications referring to this Sectional
Specification shall be of equal or higher performance level, lower performance levels are not
permitted.
1.3 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60063:1963, Preferred number series for resistors and capacitors
Amendment 1 (1967)
Amendment 2 (1977)
IEC 60068-1, Environmental testing. Part 1: General and guidance
IEC 60068-2-20, Environmental testing. Part 2: Tests. Test T: Soldering
IEC 60068-2-21, Environmental testing – Part 2-21: Tests – Test U: Robustness of termin-
ations and integral mounting devices
IEC 60068-2-45, Environmental testing. Part 2: Tests. Test XA and guidance: Immersion in
cleaning solvents
IEC 60068-2-58, Environmental testing – Part 2-58: Tests – Test Td – Test methods for
solderability, resistance to dissolution of metallization and to soldering heat of surface
mounting devices (SMD)
IEC 60393-1:1989, Potentiometers for use in electronic equipment – Part 1: Generic
Specification
Amendment 1 (1992)
IEC 60410:1973, Sampling plans and procedures for inspection by attributes

60393-6  IEC:2003(E) – 5 –
IEC QC 001001:2000, IEC Quality Assessment System for Electronic Components (IECQ) –
Basic rules
IEC QC 001002-3:1998, IEC Quality Assessment System for Electronic Components (IECQ) –
Rules of procedure – Part 3: Approval procedures
1.4 Information to be given in a Detail Specification
Detail Specifications shall be derived from the relevant Blank Detail Specification.
Detail Specifications shall not specify requirements inferior to those of the generic, sectional
or Blank Detail Specification.
When more severe requirements are included, they shall be listed in 1.8 of the Detail
Specification and indicated in the test schedules, for example by an asterisk.
NOTE The information given in 1.4.1 and 1.4.3 may, for convenience, be presented in tabular form.
The following information shall be given in each Detail Specification and the values quoted
shall preferably be selected from those given in the appropriate Clause of this Sectional
Specification.
1.4.1 Outline drawing and dimensions
The Detail Specification shall incorporate an illustration of the surface mount preset poten-
tiometer as aid to easy recognition and for comparison of the surface mount potentiometer
with others.
Dimensions and their associated tolerances, which affect interchangeability and mounting,
shall be given in the Detail Specification. All dimensions shall be stated in millimetres.
Normally the numerical values shall be given for the length, width and thickness of the body.
Where space is insufficient to show the detail dimensions required for inspection purposes,
such dimensions shall appear on the drawing forming an annex to the Detail Specification.
Recommended land patterns shall be given in Detail Specification.
When the outline drawing is other than described above, the Detail Specification shall state
such dimensional information as will adequately describe the surface mount potentiometer.
1.4.2 Mounting
The Detail Specification shall give guidance on methods of mounting for normal use.
Mounting for test and measurement purposes (when required) shall be in accordance with the
following Subclauses , unless otherwise specified.
1.4.2.1 Surface mount potentiometers shall be mounted on a suitable substrate; the method
of mounting will depend on the potentiometer construction. The Detail Specification shall
indicate which material is to be used for electrical measurements.
The substrate shall have metallized land areas of proper spacing to permit mounting of
surface mount potentiometers, and it shall provide electrical connection to the surface mount
potentiometer terminals. The details shall be specified in the Detail Specification.
___________
The text of 1.4.2 and its Subclauses will be integrated in a future edition of IEC 60393-1.

– 6 – 60393-6  IEC:2003(E)
Examples of test substrates for mechanical and electrical tests are shown in Figures 1 and 2
respectively. If another mounting method applies, the method should be clearly described in
the Detail Specification.
1.4.2.2 When the Detail Specification specifies wave soldering, a suitable glue, details of
which may be specified in the Detail Specification, shall be used to fasten the component to
the substrate before soldering is performed.
Small dots of glue shall be applied between the conductors of the substrate by means of a
suitable device securing repeatable results.
The surface mount potentiometers shall be placed on the dots using tweezers. In order to
ensure that no glue is applied to the conductors, the surface mount potentiometers shall not
be moved about.
The substrate with the surface mount potentiometers shall be heat-treated in an oven at
100 °C for 15 min.
The substrate shall be soldered in a wave soldering apparatus. The apparatus shall be
adjusted to have a pre-heating temperature of 80 °C to 100 °C, a solder bath at 260 °C
± 5 °C, and a soldering time of 5 s ± 0,5 s.
The soldering operation shall be repeated a second time (two cycles in total).
The substrate shall be cleaned for 3 min in a suitable solvent (see 3.1.2 of IEC 60068-2-45).
1.4.2.3 When the Detail Specification specifies reflow soldering, the following mounting
procedure applies:
a) The solder used, in preform or paste form, shall be silver bearing (2 % minimum) eutectic
Sn/Pb solder together with a non-activated flux, as stated in test T of IEC 60068-2-20.
Alternative solders, such as 60/40 or 63/37 may be used on surface mounts whose
construction includes solder leach barriers.
b) The surface mount potentiometer shall then be placed across the metallized land areas of
the test substrate so as to make contact between surface mount and substrate land areas.
c) The substrate shall then be placed in or on a suitable heating system (molten solder, hot
plate, tunnel oven, etc.). The temperature of the unit shall be maintained between 215 °C
and 260 °C, until the solder melts and reflows forming a homogeneous solder bond, but for
not longer than 10 s.
NOTE 1  The flux is removed by a suitable solvent (see 3.1.2 of IEC 60068-2-45). All subsequent handling is
such as to avoid contamination. Care is taken to maintain cleanliness in test chambers and during post test
measurements.
NOTE 2  The Detail Specification may require a more restricted temperature range.
NOTE 3  If vapour phase soldering is applied, the same method may be used with the temperatures adapted.

60393-6  IEC:2003(E) – 7 –
Dimensions in millimetres.
0,5 ± 0,1
0,5 ± 0,1
2 ± 0,1
3 ± 0,1
W
Note 3
Note 2
IEC  1420/03
Key
Solderable areas.
Areas which shall not be solderable (covered with non-solderable lacquer).
Dimensions not given should be chosen according to the design and size of the specimens to be tested.
NOTE 1  Material: Epoxide woven glass.
Thickness: 1,6 mm ± 0,1 mm.
NOTE 2  This conductor may be omitted or used as a guard electrode.
NOTE 3  Dimension W is dependent on the design of the test equipment.
Figure 1 – Suitable substrate for mechanical and electrical tests
(may not be suitable for impedance measurements)

– 8 – 60393-6  IEC:2003(E)
Dimensions in millimetres.
5 mm
Note 2
1           2            3            4          5           6
30 mm
IEC  1421/03
Key
Solderable areas.
Areas which shall not be solderable (covered with non-solderable lacquer).
Dimensions not given should be chosen according to the design and size of the specimens to be tested.
NOTE 1  Material: 90 % to 98 % alumina.
Thickness: 0,635 mm ± 0,05 mm.
NOTE 2  This conductor may be omitted or used as a guard electrode.
Figure 2 – Suitable substrate for electrical tests
1.4.3 Style (See 2.2.3 of IEC 60393-1)
The style shall be presented by a double letter code for example AB, which is arbitrarily
chosen for each Detail Specification.
The style designation therefore has no meaning unless the number of the Detail Specification
is also given.
1.4.4 Resistance law
The resistance law is generally not verified. If required, the Detail Specification shall prescribe
the measuring points and the associated limits for the output ratio and shall specify the
position of the corresponding tests in the test schedules.
1.4.5 Ratings and characteristics
The ratings and characteristics shall be in accordance with the relevant Clauses of this
Sectional Specification together with the following:
1.4.5.1 Rated resistance range
See 2.2.1. The preferred values are those of the E-series of IEC 60063 and/or the 1,
2, 5 series.
NOTE  When products approved to the Detail Specification have different ranges, the following statement should
be added: “The range of values available in each style is given in the register of approvals”.
1.4.5.2 Bump and shock
The bump and shock tests are considered to be alternatives. The Detail Specification shall
indicate which test has been selected.

60393-6  IEC:2003(E) – 9 –
1.4.6 Marking
The Detail Specification shall specify the content of the marking on the surface mount preset
potentiometer and on the body.
Surface mount preset potentiometers are generally not marked on the body. If some marking
can be applied, the surface mount preset potentiometer shall be clearly marked with the rated
resistance and many of the remaining items in 2.4 of IEC 60393-1.
All items shall be marked on the package. Deviations from the above mentioned requirements
shall be specifically stated.
2 Preferred ratings, characteristics and test severities
2.1 Preferred characteristics
The values given in the Detail Specification shall preferably be selected from the following:
2.1.1 Preferred climatic categories
The surface mount preset potentiometers covered by this Sectional Specification are
classified into climatic categories according to the general rules given in IEC 60068-1.
The lower and upper category temperature and the duration of the damp heat, steady state
test shall be chosen from the following:
Lower category temperature: −65 °C, -55 °C, −40 °C and −25 °C
Upper category temperature: +70 °C, +85 °C, +100 °C, +125 °C and +155 °C
Duration of the damp heat, steady state test: 4, 10, 21 and 56 days.
The severities for the cold and dry heat tests are the lower and upper category temperatures
respectively. Because of the construction of some surface mount preset potentiometers, these
temperatures will occur between two of the preferred temperatures given in the IEC 60068-2
series. In this case, the nearest preferred temperature within the actual temperature range of
the surface mount preset potentiometer shall be chosen for this severity.
2.1.2 Temperature coefficients and temperature characteristics of resistance
The preferred limits of change in resistance for the temperature characteristic of resistance
are given in Table 1.
Each line in the Table gives the preferred temperature coefficient and corresponding
temperature characteristics for 20 °C to 70 °C and limits of change in resistance for the
measurement of the temperature characteristic of resistance (see 4.14 of IEC 60393-1) on
the basis of the category temperature ranges of 2.1.1 of this Sectional Specification.

– 10 – 60393-6  IEC:2003(E)
Table 1 – Temperature coefficients and temperature characteristics of resistance
Temper- Temper- Temperature characteristic of resistance
ature ature (limits of percentage change in resistance)
coeffi- charac-
Reference temperature/ Reference temperature/
cient teristic
lower category temperature upper category temperature
20/70 °C
−6
10 /K % +20/−65 +20/−55 +20/−40 +20/−25 +20/+85 +20/+100 +20/+125 +20/+155
±1 000 ±5 ±8,5 ±7,5 ±6 ±4,5 ±6,5 ±8 ±10,5 ±13,5
± 750 ±3,75 ±6,4 ±5,63 ±4,5 ±3,38 ±4,88 ±6 ±7,88 ±10,13
±3,75 ±3 ±2,25 ±3,25 ±4 ±5,25 ±6,75
± 500 ±2,5 ±4,3
± 250 ±1,25 ±2,15 ±1,88 ±1,5 ±1,13 ±1,62 ±2 ±2,62 ±3,38
± 150 ±0,75 ±1,3 ±1,15 ±0,9 ±0,68 ±0,98 ±1,2 ±1,6 ±2,05
± 100 ±0,5 ±0,85 ±0,75 ±0,6 ±0,45 ±0,65 ±0,8 ±1,05 ±1,35
± 50 ±0,25 ±0,43 ±0,375 ±0,3 ±0,23 ±0,325 ±0,4 ±0,525 ±0,675
± 25 ±0,125 ±0,215 ±0,188 ±0,15 ±0,113 ±0,162 ±0,2 ±0,262 ±0,34
NOTE 1  Potentiometers having an upper category temperature of +85 °C need not be measured between 20 °C
and 70 °C.
NOTE 2  If measurements are required at additional temperatures, these shall be specified in the Detail
Specification.
60393-6  IEC:2003(E) – 11 –
2.1.3 Limits for change in resistance and output ratio
For each stability class, the preferred limits for change in resistance and output ratio for each
of the tests listed in the heading of Table 2 are as indicated.
Table 2 – Limits for change in resistance and output ratio
Stability 4.38 4.34 2.1.3.1 of this 4.43.2 4.22 4.35
Electrical Thrust and Vibration
class Climatic sequence Change of Sectional
temperature Specification endurance pull on
4.39
Shear at 70 °C spindle
Damp heat,
steady state 2.1.3.2 of this 4.43.3
Sectional Electrical
4.40
Specification endurance at
Mechanical
Substrate upper category
endurance
bending test temperature
4.43.2
2.1.3.3 of this
Electrical
Sectional
endurance at 70 °C
Specification
Resistance to
4.43.3
soldering heat
Electrical
endurance at
4.35
upper category
Vibration
temperature
4.36
Bump
4.37
Shock
U
ab
Δ
ΔΔΔΔR between terminals a and c ΔΔΔΔR between
U
ac
terminals a and
b
(See NOTE 2)
10 ±5 % ±7,5 %
±(10 % R+0,5 Ω) ±(5 % R+0,1 Ω) ±(5 % R+0,1 Ω) ±(15 % R+0,5 Ω)
5 ±2 % ±3 %
±(5 % R+0,1 Ω) ±(3 % R+0,1 Ω) ±(2 % R+0,1 Ω) ±(7,5 % R+0,1 Ω)
3 ±1 % ±2 %
±(3 % R+0,1 Ω) ±(2 % R+0,1 Ω) ±(1 % R+0,05 Ω) ±(5 % R+0,1 Ω)
2 ±1 % ±2 %
±(2 % R+0,1 Ω) ±(2 % R+0,1 Ω) ±(1 % R+0,05 Ω) ±(3 % R+0,1 Ω)
NOTE 1  The clause numbers in the heading of the Table refer to IEC 60393-1, unless otherwise specified.
U
ab
NOTE 2  The change in the output voltage ratio Δ shall be expressed in percent of the total applied voltage.
U
ac
2.1.3.1 Shear (adhesion) test
2.1.3.1.1 Test conditions: the surface mount potentiometer shall be mounted as described
in 1.4.2.
The potentiometer shall be subjected to test Ue of IEC 60068-2-21, under the following
condition.
A force of 5 N shall be applied to the surface mount potentiometer body progressively, without
shock, and shall be maintained for a period of 10 s ± 1 s.
2.1.3.1.2 Requirements: the surface mount potentiometer shall be visually examined in the
mounted state. There shall be no visible damage.
___________
The text of 2.1.3.1, 2.1.3.2, 2.1.3.3 and 2.1.3.4 and their Subclauses will be integrated in a future edition of
IEC 60393-1.
– 12 – 60393-6  IEC:2003(E)
2.1.3.2 Substrate bending test (formerly bond strength of the end face plating)
2.1.3.2.1 The surface mount potentiometer shall be mounted on an epoxide woven glass
printed board, as described in 1.4.2.
2.1.3.2.2 The resistance of the surface mount potentiometer shall be measured as specified
in 4.6 of IEC 60393-1.
2.1.3.2.3 The potentiometer shall be subjected to test Ue of IEC 60068-2-21 using the
conditions as prescribed in the relevant Specification for deflection D and the number of
bends.
2.1.3.2.4 The resistance of the surface mount potentiometer shall be measured as specified
in 4.6 of IEC 60393-1, with the board in the bent position. The change in resistance compared
with that measured in 2.1.3.2.2 shall not exceed the value specified in the Detail
Specification.
2.1.3.2.5 The printed board shall be allowed to recover from the bent position and then
removed from the test jig.
2.1.3.2.6 Final inspection and requirements: the surface mount potentiometers shall be
visually examined and there shall be no visible damage.
2.1.3.3 Resistan
...