IEC 61191-2:2017

IEC 61191-2 ®
Edition 3.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Printed board assemblies –
Part 2: Sectional specification – Requirements for surface mount soldered
assemblies
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IEC 61191-2 ®
Edition 3.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Printed board assemblies –
Part 2: Sectional specification – Requirements for surface mount soldered

assemblies
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.190; 31.240 ISBN 978-2-8322-4322-0

– 2 – IEC 61191-2:2017 © IEC 2017
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 General requirements . 7
5 Surface mounting of components . 7
5.1 General . 7
5.2 Alignment requirements . 8
5.3 Process control . 8
5.4 Surface mounted component requirements . 8
5.5 Flatpack lead forming . 8
5.5.1 General . 8
5.5.2 Surface mounted device lead bends . 8
5.5.3 Surface mounted device lead deformation . 9
5.5.4 Flattened leads . 9
5.5.5 Dual-in-line packages (DIPs) . 9
5.5.6 Parts not configured for surface mounting . 9
5.6 Small devices with two terminations . 9
5.6.1 General . 9
5.6.2 Stack mounting . 9
5.6.3 Devices with external deposited elements . 9
5.7 Lead component body positioning . 10
5.7.1 General . 10
5.7.2 Axial-leaded components . 10
5.7.3 Other components . 10
5.8 Parts configured for butt lead mounting . 10
5.9 Non-conductive adhesive coverage limits . 10
6 Acceptance requirements . 10
6.1 General . 10
6.2 Control and corrective actions . 10
6.3 Surface soldering of leads and terminations . 11
6.3.1 General . 11
6.3.2 Solder fillet height and heel fillets . 11
6.3.3 Flat ribbon L and gull-wing leads . 12
6.3.4 Round or flattened (coined) leads . 13
6.3.5 J leads . 14
6.3.6 Rectangular or square end component . 15
6.3.7 Cylindrical end-cap terminations . 16
6.3.8 Bottom only terminations . 17
6.3.9 Castellated terminations . 18
6.3.10 Butt joints . 19
6.3.11 Inward L-shaped ribbon leads . 20
6.3.12 Flat lug leads . 21
6.3.13 Ball grid array . 22
6.3.14 Column grid array . 23
6.3.15 Bottom termination components . 24

6.3.16 Components with bottom thermal plane terminations (D-Pak) . 24
6.3.17 P-style terminations . 26
6.4 General post-soldering requirements applicable to all surface-mounted
assemblies . 26
6.4.1 Dewetting . 26
6.4.2 Leaching . 26
6.4.3 Pits, voids, blowholes, and cavities . 26
6.4.4 Solder wicking . 27
6.4.5 Solder webs and skins . 27
6.4.6 Bridging . 27
6.4.7 Degradation of marking . 27
6.4.8 Solder spikes . 27
6.4.9 Disturbed joint . 27
6.4.10 Component damage. 27
6.4.11 Open circuit, non-wetting . 27
6.4.12 Component tilting. 27
6.4.13 Non-conducting adhesive encroachment . 28
6.4.14 Open circuit, no solder available . 28
6.4.15 Component on edge . 28
7 Rework and repair . 28
Annex A (normative) Placement requirements for surface mounted devices . 30
A.1 General . 30
A.2 Component positioning . 30
A.3 Small devices incorporating two terminations . 30
A.3.1 Metallization coverage over the land (side-to-side) . 30
A.3.2 Metallization coverage over the land (end) . 30
A.4 Mounting of cylindrical end-cap devices (MELFs) . 30
A.5 Registration of castellated chip carriers . 30
A.6 Surface mounted device lead and land contact . 30
A.7 Surface mounted device lead side overhang . 30
A.8 Surface mounted device lead toe overhang . 31
A.9 Surface mounted device lead height off land (prior to soldering) . 31
A.10 Positioning of J lead devices . 31
A.11 Positioning gull-wing lead devices . 31
A.12 External connections to packaging and interconnect structures . 31
Bibliography . 32

Figure 1 – Lead formation for surface mounted device . 8
Figure 2 – Fillet height . 12
Figure 3 – Flat ribbon and gull-wing leads . 13
Figure 4 – Round or flattened (coined) lead joint . 14
Figure 5 – J lead joint . 15
Figure 6 – Rectangular or square end components . 16
Figure 7 – Cylindrical end-cap terminations . 17
Figure 8 – Bottom only terminations . 18
Figure 9 – Leadless chip carriers with castellated terminations . 19
Figure 10 – Butt joints . 20

– 4 – IEC 61191-2:2017 © IEC 2017
Figure 11 – Inward L-shaped ribbon leads . 21
Figure 12 – Flat lug leads . 22
Figure 13 – BGA with collapsing balls . 23
Figure 14 – Bottom termination components . 24
Figure 15 – Bottom thermal plane terminations . 25
Figure 16 – P-style terminations . 26

Table 1 – BGA with non-collapsing balls . 23
Table 2 – Column grid array . 23
Table 3 – Reworkable defects . 29

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED BOARD ASSEMBLIES –
Part 2: Sectional specification –
Requirements for surface mount soldered assemblies

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61191-2 has been prepared by IEC technical committee 91:
Electronics assembly technology.
This third edition cancels and replaces the second edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the requirements have been updated to be compliant with the acceptance criteria in
IPC-A-610F;
b) some of the terminology used in the document has been updated;
c) references to IEC standards have been corrected;
d) five termination styles have been added.

– 6 – IEC 61191-2:2017 © IEC 2017
The text of this International Standard is based on the following documents:
CDV Report on voting
91/1386/CDV 91/1429/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61191 under the general title Printed board assemblies can be found
in the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
 reconfirmed,
 withdrawn,
 replaced by a revised edition, or
 amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of September 2019 have been included in this copy.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
PRINTED BOARD ASSEMBLIES –
Part 2: Sectional specification –
Requirements for surface mount soldered assemblies

1 Scope
This part of IEC 61191 gives the requirements for surface mount solder connections. The
requirements pertain to those assemblies that are totally surface mounted or to the surface
mounted portions of those assemblies that include other related technologies (e.g. through-
hole, chip mounting, terminal mounting, etc.).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 60194, Printed board design, manufacture and assembly – Terms and definitions
IEC 61191-1, Printed board assemblies – Part 1: Generic specification – Requirements for
soldered electrical and electronic assemblies using surface mount and related assembly
technologies
IPC-A-610, Acceptability of Electronic Assemblies
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60194 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 General requirements
The requirements of IEC 61191-1 are a mandatory part of this specification.
Workmanship shall meet the requirements of IPC-A-610 in accordance with the classification
requirements of this document.
5 Surface mounting of components
5.1 General
This clause covers assembly of components that are placed on the surface to be manually or
machine soldered and includes components designed for surface mounting as well as
through-hole components that have been adapted for surface mounting technology.

– 8 – IEC 61191-2:2017 © IEC 2017
5.2 Alignment requirements
Sufficient process control at all stages of design and assembly shall be in place to enable the
post-soldering alignments and solder joint fillet controls specified in 6.3 to be achieved.
Relevant factors affecting the requirements include land and conductor design, component
proximities, component and land solderability, solder paste/adhesive quantity and alignment
and component placement accuracy.
5.3 Process control
If suitable process controls are not in place to ensure compliance with 5.2 and the intent of
Annex A, the detailed requirements of Annex A shall be mandatory.
5.4 Surface mounted component requirements
The leads of lead surface mounted components shall be formed to their final configuration
prior to mounting. Leads shall be formed in such a manner that the lead-to-body seal is not
damaged or degraded and that they may be soldered into place by subsequent processes
which do not result in residual stresses decreasing reliability. When the leads of dual-in-line
packages, flatpacks, and other multilead devices become misaligned during processing or
handling, they may be straightened to ensure parallelism and alignment prior to mounting,
while maintaining the lead-to-body seal integrity.
5.5 Flatpack lead forming
5.5.1 General
Leads on opposite sides of surface mounted flatpacks shall be formed such that the
non-parallelism between the base surface of the component and the surface of the printed
board (i.e. component cant) is minimal. Component cant is permissible provided the final
configuration does not exceed the maximum spacing limit of 2,0 mm (see Figure 1).
No bend
into the seal
R
45° – 90° R
≤ 2,0 mm
IEC
Key
R lead-bend radius
T nominal lead thickness
Figure 1 – Lead formation for surface mounted device
5.5.2 Surface mounted device lead bends
Leads shall be supported during forming to protect the lead-to-body seal. Bends shall not
extend into the seal (see Figure 1). The lead-bend radius (R) shall be > 1 T (T = nominal lead
T
thickness). The angle of that part of the lead between the upper and lower bends in relation to
the mounting land shall be 45° minimum and 90° maximum.
5.5.3 Surface mounted device lead deformation
Lead deformation (unintentional bending) may be allowed when
a) no evidence of a short circuit or potential short circuit exists,
b) lead-to-body seal or weld is not damaged by the deformation,
c) does not violate minimum electrical spacing requirement,
d) top of lead does not extend beyond the top of body; preformed stress loops may extend
above the top of the body; however, stand-off height limit shall not be exceeded,
e) toe curl, if present on bends, shall not exceed two times the thickness of the lead (2 T),
f) coplanarity limits are not exceeded.
5.5.4 Flattened leads
Components with axial leads of round cross-section may be flattened (coined) for positive
seating in surface mounting. If flattening is used, the flattened thickness shall be not less than
40 % of the original diameter. Flattened areas of leads shall be excluded from the 10 %
deformation requirement in 6.5.3 of IEC 61191-1:2013.
Flattened leads on opposite sides of a surface mount part shall be formed such that the non-
parallelism between the base surface of the component and the surface of the printed board
(e.g. component cant) is minimal.
5.5.5 Dual-in-line packages (DIPs)
Dual-in-line packages may be surface mounted provided the leads are configured to meet the
mounting requirements for surface mounted loaded parts. The lead preparation operation
shall be performed using die forming/cutting systems. Hand forming and trimming of leads are
prohibited.
5.5.6 Parts not configured for surface mounting
Flatpacks of the through-hole configuration, transistors, metal power packages, and other
non-axial lead components shall not be surface mounted unless the leads are formed to meet
the surface mounted device lead forming requirements. Such applications shall be agreed on
between user and manufacturer.
5.6 Small devices with two terminations
5.6.1 General
The detailed requirements for mounting of small devices with two lead terminations are
defined in 5.6.2 and 5.6.3.
5.6.2 Stack mounting
When part stacking is permitted by the assembly drawing, parts shall not bridge spacing
between other parts or components such as terminals or other chip components.
5.6.3 Devices with external deposited elements
Components with electrical elements deposited on an external surface (such as chip resistors)
shall be mounted with that surface facing away from the printed board or substrate.

– 10 – IEC 61191-2:2017 © IEC 2017
5.7 Lead component body positioning
5.7.1 General
Parts mounted over protected surfaces and insulated parts that are positioned over circuitry
or parts mounted over surfaces without exposed circuitry may be flush mounted (i.e. no stand-
off height). Parts mounted over exposed circuitry shall have their leads formed to provide a
minimum of 0,25 mm between the bottom of the component body and the exposed circuitry.
The maximum clearance between the bottom of the leaded component body and the printed
wiring surface shall not exceed 2,0 mm.
5.7.2 Axial-leaded components
The body of a surface-mounted axial-leaded component shall be spaced from the surface of
the printed board at a maximum of 2,0 mm unless the component is mechanically attached to
the substrate by adhesive or other means. Leads on opposite sides of surface mounted
axial-leaded components shall be formed such that component cant (non-parallelism between
the base surface of the mounted component and the surface of the printed board) is minimal
and in no instance shall body cant result in non-conformance with maximum spacing limits.
5.7.3 Other components
TO-can devices, tall profile components (i.e. over 15 mm), transformers, and metal power
packages may be surface mounted provided the parts are bonded or otherwise secured to the
board in a manner which enables the part to withstand the end-item shock, vibration and
environmental stresses.
5.8 Parts configured for butt lead mounting
Components designed for through hole (pin-in-hole) applications and modified for butt joint
attachment, or stiff leaded dual-in-line packages may be butt mounted on level A and B
products. Butt mounting is not permitted on level C products unless the component is
designed for surface mounting. Components with solder-charged terminations designed for butt
mounting may be acceptable for all classes. For other butt-mounted termination components
acceptance criteria have to be agreed between the manufacturer and the user.
5.9 Non-conductive adhesive coverage limits
Non-conductive adhesive materials, when used for component mounting, shall not flow onto,
or obscure, areas to be soldered or into vias or plated-through holes.
6 Acceptance requirements
6.1 General
Materials, processes, and procedures described and specified in IEC 61191-1 provide for
soldered interconnections that are better than the minimum surface mount acceptance
requirements in this clause. Processes and their control should be capable of producing
product meeting or exceeding the acceptance criteria for defined product levels.
6.2 Control and corrective actions
The detailed requirements for acceptance, corrective action limits, control limit determination,
and general assembly criteria described in IEC 61191-1 are a mandatory part of this standard.
In addition 6.3 shall be met for all surface mount assembly and for connection acceptability.

6.3 Surface soldering of leads and terminations
6.3.1 General
Solder joints or terminations on components designed for surface mounting shall exhibit
solder joints that meet the general descriptions of Clause 10 of IEC 61191-1:2013 with the
specific measurements defined in 6.3.3 to 6.3.17 of this document. Some surface-mounted
components will self-align during reflow soldering but a degree of misalignment is permitted to
the extent specified. However, minimum design conductor spacing shall not be violated.
In 6.3.3 to 6.3.17, certain joint features are unspecified in size and the only requirement is
that a properly wetted fillet to both lead/termination and lands be visible. Geometric
dimensions not called out with any requirements are considered non-critical to the
performance of the interconnection.
Surface-mounted joints formed to connector, socket, and other leads or terminations without
mechanical support, subjected to stress from insertion and withdrawal of components or
printed boards, shall meet the requirements of level C.
6.3.2 Solder fillet height and heel fillets
6.3.2.1 General
The height F of solder fillets, including heel fillets, as required in the following subclauses
shall be judged by the distance the applied solder has risen up the joined surface. Figure 2
illustrates this measurement for joints of equal height but having different solder volume. In
6.3.3 to 6.3.12, for some lead configurations, the minimum acceptable fillet height criterion is
referenced to the lead thickness T, or one half the thickness (0,5 T). When referenced to T,
the height of the heel fillet to a formed lead shall be measured at the lowest point of the inside
bend radius of the lead, as indicated by point A of Figure 2b (e.g. level C in Figures 3 to 5).
When referenced to 0,5 T, the fillet may be 0,5 T lower (e.g. level B in Figures 3 to 5).
NOTE Subclause 6.3.3 provides an organization that combines the requirement paragraph, the appropriate figure
and a dimensional table that describes the specific details.
6.3.2.2 Solder connection contours
A mounting technique shall be used to compensate for the coefficient of thermal expansion
(CTE) mismatch of the part and board. This mounting technique shall be limited to part leads,
specialized mounting devices, and normal solder connections. The use of specialized stand-
offs mounted between the part and the land is permissible. Leadless components shall not be
soldered into place using redundant interconnect wiring between the component castellation
and the land.
Designs that use special solder connection contours as part of a CTE mismatch compensation
system shall be identified on the approval assembly drawing. The mounting technique shall be
capable of performing with a solder connection which meets the requirements of this
document.
6.3.2.3 Surface mount device lead heel position
The heel of a leaded component shall not overhang the land.
NOTE The heel begins where the lead starts to curve at the lead bend.
6.3.2.4 Break-away tie bars
Components (e.g. connectors and flexible circuits) which incorporate break-away tie bars in
their design may be installed or soldered in place prior to removal of the tie bar. Exposed
basis metal resulting from tie bar removal is permissible.

– 12 – IEC 61191-2:2017 © IEC 2017
F = fillet height
IEC
a) Fillet height
L = projected lead length
T = lead thickness
T
A = lowest point of inside
bend radius A
L L
IEC
b) Fillet height referenced to lead thickness
Key
A lowest point of inside bend radius
F fillet height
L projected lead length
T lead thickness
Figure 2 – Fillet height
6.3.3 Flat ribbon L and gull-wing leads
Solder joints between substrate lands and flat ribbon leads formed into an L, and gull-wing
shaped component leads of either stiff or flexible materials shall meet the alignment and
solder fillet requirements of Figure 3 for each product level.
F
F
F
Lead
L
W
L
B
W
A
A
B
W
Land
C
Side overhang Toe overhang
Others lead configurations
End joint width
g
a
See Note
See note
of the table
of the table
Line bisecting
lower bend radius
Center line of T
D D
Toe down heel fillet height
D = side joint length W = lead width T = lead thickness L = formed foot length

IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C

d d d
Maximum side overhang ½W or 0,5 mm, ½W or 0,5 mm, ¼W or 0,5 mm,
A
whichever is less whichever is less whichever is less
Maximum toe overhang Not permitted when Not permitted when
d
B
d d
L < 3W L < 3W
c
Minimum end joint width C ½W ½W ¾W
Minimum side
When L ≥ 3W
3W or ¾L, whichever is longer
b
W or 0,5mm,
joint length
D
whichever is less
When L < 3W L
f
Maximum heel fillet height E
Minimum heel T ≤ 0,4 mm G + T
e f
F G + T
fillet height
T > 0,4 mm G + ½T
e e e
Minimum solder thickness G
a
Solder fillets for levels A and B may extend through the top bend.
b
Leads not having wettable sides or ends by design (such as leads stamped or sheared from prepared stock)
are not required to have side or end fillets, but side overhang is not permitted (all levels).
c, d
Shall not violate minimum design conductor spacing.
e
Properly wetted fillet evident.
f
Solder does not touch body or end seal.
g
In case of toe down configuration, minimum fillet height F extends at least to the mid-point of the outside lead
bend.
Figure 3 – Flat ribbon and gull-wing leads
6.3.4 Round or flattened (coined) leads
Joints formed to round or flattened (coined) leads shall meet the dimensional and fillet
requirements of Figure 4 for each product level.
E
F
T
G
E
F
G
T
G
F
T
G
– 14 – IEC 61191-2:2017 © IEC 2017
W
W
L
A
A
A C
A C
Side overhang Toe overhang
B
End joint width
a
See note
of the table
Line bisecting
W = flattened lead width or
lower bend
diameter of round lead
radius
T = thickness of lead at joint
site (cover land)
L = formed foot length
D
Others land configurations
Toe down heel
fillet height
Side joint length
IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C
Maximum side overhang ¼W or 0,5 mm,
b
A ½W or 0,5 mm, whichever is less
b
whichever is less
b b b
Maximum toe overhang B
c c
Minimum end joint width C ¾W
Minimum side joint length D W 1½W
a a a
Maximum heel fillet height E
c d d
Minimum heel fillet height F G + ½T G + T
c c c
Minimum solder thickness G
c
Minimum side joint height Q G + ½T G + ½T
a
Solder does not touch package body or seal.
b
Shall not violate minimum design conductor spacing.
c
Properly wetted fillet evident.
d
In case of toe down configuration, minimum heel fillet height F extends at least to the mid-point of the outside
lead bend
Figure 4 – Round or flattened (coined) lead joint
6.3.5 J leads
Joints formed to leads having a J shape at the joint site shall meet the dimensional and fillet
requirements of Figure 5 for each product level.
E
F
T
G
F
G
Q
G
Q
W
Lead
W
T
A
Toe overhang
C
Land
Side overhang
A
a
See note
B
of the table
End joint width
T
W = lead width
T = lead thickness
D
Side joint length
IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C
d
A ½W ½W ¼W
Maximum side overhang
b d b d b d
Maximum toe overhang B
Minimum end joint width C ½W ¾W
c
Minimum side joint length D 1½W 1½W
a a a
Maximum fillet height E
Minimum fillet height F G + ½T G + T
c c c
Minimum solder thickness G
a
Maximum solder fillet does not touch package body or end seal.
b
Unspecified parameter.
c
Properly wetted fillet evident.
d
Shall not violate minimum design conductor spacing.
Figure 5 – J lead joint
6.3.6 Rectangular or square end component
Solder joints to components having terminations of a square or rectangular configuration shall
meet the dimensional and solder fillet requirements of Figure 6 for each product level.
E
F
G
G
– 16 – IEC 61191-2:2017 © IEC 2017
W
W
Side overhang
of termination
A
C
A
P
P
End overhang B
a
End joint width
See note
T
of the table
W W W
J D
One or Three face Five face
two-sided termination termination
End overlap
termination
Termination configurations
H = height of termination zone T = length of termination zone
W = width of termination area P = width of land

IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C
e
Maximum side overhang ¼W or P,
A ½W or P, whichever is less
whichever is less
End overhang B Not permitted
Minimum end joint width ¾W or P,
C ½W or P, whichever is less
whichever is less
c d
Minimum side joint length D
a a
Maximum fillet height E
Minimum fillet height G + ¼H or G + 0,5,
d
F
whichever is less
b d
Minimum solder thickness G
c
Minimum end overlap J required ¼T
a
The maximum fillet may overhang the land or extend onto the top of the end-cap metallization; however, the
solder shall not extend further onto the component body.
b
Unless satisfactory cleaning can be demonstrated with reduced clearance. G is not specified when cleaning is
not required.
c
Not required for one face only termination type components.
d
Properly wetted fillet evident.

e
Shall not violate minimum design conductor spacing.
Figure 6 – Rectangular or square end components
6.3.7 Cylindrical end-cap terminations
Solder joints to components having cylindrical end-cap terminations (e.g. MELFs) shall meet
the dimensional and solder fillet requirements of Figure 7 for each product level.
E
G
H
F
H
G
F
W
A A
B
C
Side overhang
a
See note End overhang
of the table
P
T
End joint width
W = diameter of termination
T = termination / plating length
S = land length
D
J
S
Side joint length
and end overlap
IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C
c
Maximum side overhang A ¼W or P, whichever is less
End overhang B Not permitted
b
Minimum end joint width C ½W or P, whichever is less
b
Minimum side joint length D ½T or S, ¾T or S,
whichever is less whichever is less
a
Maximum fillet height E
(end and side)
b
Minimum fillet height F G + ¼W or
(end and side)
G + 1,0 mm,
whichever is less
b
Minimum solder thickness G
b
Minimum end overlap J ¼T ¾T
a
The maximum fillet may overhang the land or extend onto the top of the end-cap metallization; however, the
solder shall not extend further onto the component body.
b
Properly wetted fillet evident.

c
Shall not violate minimum design conductor spacing.
Figure 7 – Cylindrical end-cap terminations
6.3.8 Bottom only terminations
Discrete chip components, leadless chip carriers, and other devices having metallized
terminations on the bottom side only shall meet the dimensional and solder fillet requirements
of Figure 8 for each product level.
E
G
F
F
– 18 – IEC 61191-2:2017 © IEC 2017
T
A
W
J
C
P B
A
Side overhang
End overhang End joint width
W = termination width
T = termination length
P = land width
D
B
Side joint length
IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C

d
Maximum side overhang A ½W or P, whichever is less ¼W or P,

d
whichever is less
End overhang B Not permitted
Minimum end joint width C ½W or P, whichever is less ¾W or P,
whichever is less
a a a
Minimum side joint length D
a a a
Maximum fillet height E
a a a
Minimum fillet height F
b b b
c
Minimum solder thickness G
b
Minimum end overlap J ½T ¾T
a
Unspecified parameter.
b
Properly wetted fillet evident.
c
If cleaning is required, G is not specific as long as satisfactory cleaning can be demonstrated with reduced
clearance.
d
Shall not violate minimum design conductor spacing.
Figure 8 – Bottom only terminations
6.3.9 Castellated terminations
Joints formed to castellated terminations of leadless chip carriers shall meet the dimensional
and solder fillet requirements of Figure 9 for each product level.
G
F
G
E
W
B
Corner metallization
(termination)
A A
Fillet required if
Side overhang Side overhang
land is present
A C
D
P
Side joint length End joint width
W = castellation width
H = castellation height
P = land length external
to package
IEC
Dimensions in millimetres
Feature Dimension Level A Level B Level C

d
Maximum side overhang A ½W ½W ¼W
End overhang B Not permitted Not permitted Not permitted
Minimum end joint width C ½W ½W ¾W
a c
Minimum side joint length D Depth of castellation
a d
Maximum fillet height E
c
Minimum fillet height F
G + ¼H G + ½H
c
b
Minimum solder thickness G
a
The maximum fillet may extend beyond the top of castellation provided it does not contact the body

b
If cleaning is required, G is not specific as long as satisfactory cleaning can be demonstrated with reduced
clearance.
c
Properly wetted fillet evident.

d
Shall not violate minimum design conductor spacing.
Fig
...