Printed boards and printed board assemblies - Design and use - Part 6-4: Land pattern design - Generic requirements for dimensional drawings of surface mounted components (SMD) from the viewpoint of land pattern design

This standard specifies generic requirements for dimensional drawings of SMD from the viewpoint of land pattern design. The purpose of this document is to prevent land pattern design issues caused by lack of information and/or misuse of the information from SMD outline drawing as well as to improve the utilization of IEC 61188 series. This document is applicable to the SMD of semiconductor devices and electrical components.

Leiterplatten und Flachbaugruppen - Konstruktion und Anwendung - Teil 6-4: Konstruktion des Anschlussflächenbilds - Allgemeine Anforderungen an SMD-Maßzeichnungen hinsichtlich der Konstruktion des Anschlussflächenbilds

Cartes imprimées et cartes imprimées équipées - Conception et utilisation - Partie 6-4: Conception de la zone de report - Exigences génériques pour les dessins dimensionnels de composants montés en surface (CMS) du point de vue de la conception de la zone de report

L'IEC 61188-6-4:2019 spécifie les exigences génériques pour les dessins dimensionnels de CMS du point de vue de la conception de la zone de report. Le présent document a pour objet d'éviter les problèmes de conception de la zone de report causés par un manque d'informations et/ou une mauvaise utilisation des informations provenant des dessins d'encombrement de CMS, ainsi que d'améliorer l'utilisation de la série IEC 61188. Le présent document est applicable au CMS de dispositifs à semiconducteurs et de composants électriques.

Plošče tiskanih vezij in sestavi plošč tiskanih vezij - Zasnova in uporaba - 6-4. del: Razmestitev priključkov - Splošne zahteve za merske risbe elementov za površinsko montažo (SMD) glede na razmestitev njihovih priključkov

Ta standard določa splošne zahteve za merske risbe elementov za površinsko montažo (SMD) glede na razmestitev njihovih priključkov. Namen tega dokumenta je preprečevanje težav pri razmestitvi priključkov zaradi pomanjkanja informacij in/ali zlorabe informacij iz opisa risbe elementov za površinsko montažo ter izboljšana uporaba skupine standardov IEC 61188. Ta dokument se uporablja za elemente za površinsko montažo polprevodniških elementov in električnih komponent.

General Information

Status
Published
Publication Date
14-Oct-2019
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-Jul-2019
Due Date
29-Sep-2019
Completion Date
15-Oct-2019

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SLOVENSKI STANDARD
SIST EN IEC 61188-6-4:2019
01-november-2019

Plošče tiskanih vezij in sestavi plošč tiskanih vezij - Zasnova in uporaba - 6-4. del:

Razmestitev priključkov - Splošne zahteve za merske risbe elementov za
površinsko montažo (SMD) glede na razmestitev njihovih priključkov

Printed boards and printed board assemblies - Design and use - Part 6-4: Land pattern

design - Generic requirements for dimensional drawings of surface mounted components

(SMD) from the viewpoint of land pattern design
Ta slovenski standard je istoveten z: EN IEC 61188-6-4:2019
ICS:
01.100.25 Risbe s področja Electrical and electronics
elektrotehnike in elektronike engineering drawings
31.180 Tiskana vezja (TIV) in tiskane Printed circuits and boards
plošče
SIST EN IEC 61188-6-4:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 61188-6-4:2019
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SIST EN IEC 61188-6-4:2019
EUROPEAN STANDARD EN 61188-6-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2019
ICS 31.180
English Version
Printed boards and printed board assemblies - Design and use -
Part 6-4: Land pattern design - Generic requirements for
dimensional drawings of surface mounted components (SMD)
from the viewpoint of land pattern design
(IEC 61188-6-4:2019)

Cartes imprimées et cartes imprimées équipées - Leiterplatten und Flachbaugruppen - Konstruktion und

Conception et utilisation - Partie 6-4: Conception de la zone Anwendung - Teil 6-4: Allgemeine Anforderungen an SMD-

de report - Exigences génériques pour les dessins Maßzeichnungen hinsichtlich der Konstruktion des

dimensionnels de composants montés en surface (CMS) du Anschlussflächenbilds
point de vue de la conception de la zone de report (IEC 61188-6-4:2019)
(IEC 61188-6-4:2019)

This European Standard was approved by CENELEC on 2019-06-06. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of Nort Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 61188-6-4:2019 E
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SIST EN IEC 61188-6-4:2019
EN 61188-6-4:2019 (E)
European foreword

The text of document 91/1561/FDIS, future edition 1 of IEC 61188-6-4, prepared by IEC/TC 91 "Electronics

assembly technology" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN 61188-6-4:2019.
The following dates are fixed:

• latest date by which the document has to be implemented at national level by (dop) 2020-03-06

publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2022-06-06

document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 61188-6-4:2019 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60191-1 NOTE Harmonized as EN IEC 60191-1
IEC 60191-6 NOTE Harmonized as EN 60191-6
IEC 60191-6-1 NOTE Harmonized as EN 60191-6-1
IEC 61188-5-1 NOTE Harmonized as EN 61188-5-1
IEC 61188-5-2 NOTE Harmonized as EN 61188-5-2
IEC 61188-5-3 NOTE Harmonized as EN 61188-5-3
IEC 61188-5-4 NOTE Harmonized as EN 61188-5-4
IEC 61188-5-5 NOTE Harmonized as EN 61188-5-5
IEC 61188-5-6 NOTE Harmonized as EN 61188-5-6
IEC 61188-5-8 NOTE Harmonized as EN 61188-5-8
IEC 61191-1 NOTE Harmonized as EN IEC 61191-1
IEC 61191-2 NOTE Harmonized as EN 61191-2
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SIST EN IEC 61188-6-4:2019
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu.

Publication Year Title EN/HD Year
IEC 60194 - Terms and definitions for printed circuits - -
IEC 60194-2 - Printed boards design, manufacture and
- -
assembly - Vocabulary - Part 2: Common
usage in electronic technologies as well as
printed board and electronic assembly
technologies
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SIST EN IEC 61188-6-4:2019
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SIST EN IEC 61188-6-4:2019
IEC 61188-6-4
Edition 1.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Printed boards and printed board assemblies – Design and use –
Part 6-4: Land pattern design – Generic requirements for dimensional drawings
of surface mounted components (SMD) from the viewpoint of land pattern
design
Cartes imprimées et cartes imprimées équipées – Conception et utilisation –
Partie 6-4: Conception de la zone de report – Exigences génériques pour les
dessins dimensionnels de composants montés en surface (CMS) du point
de vue de la conception de la zone de report
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180 ISBN 978-2-8322-6866-7

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 61188-6-4:2019
– 2 – IEC 61188-6-4:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms, definitions and symbols........................................................................................ 6

4 Applicable SMDs ............................................................................................................. 8

5 Requirements .................................................................................................................. 9

5.1 Figures and dimensional symbols ........................................................................... 9

5.2 Common requirements ............................................................................................ 9

5.2.1 General ........................................................................................................... 9

5.2.2 Requirements for solder joint fillet design ........................................................ 9

5.2.3 Requirements for courtyard design ................................................................ 10

5.2.4 Height parameters ......................................................................................... 10

5.2.5 Bottom view ................................................................................................... 12

5.2.6 Detail view ..................................................................................................... 12

5.2.7 Distinguish between metal and resin .............................................................. 12

5.2.8 Consistency of various dimensions ................................................................ 12

5.2.9 The relation between a land pattern and an element-placement position ........ 13

5.2.10 Coplanarity .................................................................................................... 14

5.3 Requirements for a specific SMD .......................................................................... 14

5.3.1 General ......................................................................................................... 14

5.3.2 End-terminal type .......................................................................................... 14

5.3.3 Gull-wing terminals type, inward L-shaped ribbon terminals type and

under-body L type .......................................................................................... 18

5.3.4 Bottom surface terminal type and flat lug terminals type ................................ 30

6 Supplementary dimensions ............................................................................................ 39

Bibliography .......................................................................................................................... 40

Figure 1 – Example of the dimensional relationship to the drawings of SMDs, the land

pattern design and the after soldering state .......................................................................... 12

Figure 2 – Example of dimensional consistency for an asymmetrical SMD ............................ 13

Figure 3 – Example of the direction of recommendation for land pattern position of an

asymmetrical SMD ................................................................................................................ 14

Figure 4 – Influence of good and bad (after soldering) coplanarity ........................................ 14

Figure 5 – Example of the dimensional relationship between the drawings of

components with rectangular terminals and the land pattern design ...................................... 16

Figure 6 – Example of the dimensional notations for a component with rectangular

terminals ............................................................................................................................... 17

Figure 7 – Example of the dimensional notations for cylindrical components with end

cap terminals ........................................................................................................................ 18

Figure 8 – Example of the dimensional relationship between the drawings of gull-wing

terminals type and the land pattern design ............................................................................ 19

Figure 9 – Example of the dimensional notations for gull-wing terminals type (QFP) ............ 20

Figure 10 – Details of terminal (case 1) ................................................................................ 21

Figure 11 – Details of terminal (case 2) ................................................................................ 22

Figure 12 – Details of terminal (case 3) ................................................................................ 22

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SIST EN IEC 61188-6-4:2019
IEC 61188-6-4:2019 © IEC 2019 – 3 –

Figure 13 – Details of terminal (case 4) ................................................................................ 23

Figure 14 – Details of terminal (case 5) ................................................................................ 23

Figure 15 – Example of the dimensional relationship between the drawings of inward

L-shaped ribbon terminals type and the land pattern design .................................................. 24

Figure 16 – Example of the dimensional notations for inward L-shaped ribbon terminals

type ...................................................................................................................................... 25

Figure 17 – Example of the dimensional notations for under-body L type .............................. 26

Figure 18 – Terminal shape expansion drawing of under-body L type (capacitor) .................. 27

Figure 19 – Example of the dimensional notations for a connector ........................................ 28

Figure 20 – The cross-sectional a-a detail (terminal shape) of Figure 18, side view .............. 29

Figure 21 – Example of the drawing showing the moving range (lock lever open state) ......... 29

Figure 22 – Example of the upper surface cap constitution ................................................... 29

Figure 23 – Example of the dimensional relationship between the drawings of a BGA

and the land pattern design................................................................................................... 31

Figure 24 – Example of the dimensional notations for BGA ................................................... 32

Figure 25 – Example of details of solder balls (side view) ..................................................... 33

Figure 26 – Example of the dimensional relationship between the drawings of QFN and

the land pattern design ......................................................................................................... 34

Figure 27 – Example of the dimensional notations for bottom surface terminals .................... 36

Figure 28 – Example of the dimensional relationship between the drawings of flat lug

terminals type and the land pattern design ............................................................................ 38

Figure 29 – Example of the dimensional notations for flat lug terminals type ......................... 39

Figure 30 – Example of the recommended dimensions in the tray ......................................... 39

Table 1 – Reference symbols used in this document ............................................................... 7

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SIST EN IEC 61188-6-4:2019
– 4 – IEC 61188-6-4:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED BOARDS AND PRINTED BOARD ASSEMBLIES –
DESIGN AND USE –
Part 6-4: Land pattern design – Generic requirements for dimensional
drawings of surface mounted components (SMD) from the viewpoint of
land pattern design
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

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC

Publication(s)"). 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. 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 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 IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

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 61188-6-4 has been prepared by IEC technical committee 91:

Electronics assembly technology.
The text of this International Standard is based on the following documents:
FDIS Report on voting
91/1561/FDIS 91/1572/RVD

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.

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SIST EN IEC 61188-6-4:2019
IEC 61188-6-4:2019 © IEC 2019 – 5 –

A list of all parts in the IEC 61188 series, published under the general title Printed boards and

printed board assemblies – Design and use, can be found on 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.

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.
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SIST EN IEC 61188-6-4:2019
– 6 – IEC 61188-6-4:2019 © IEC 2019
PRINTED BOARDS AND PRINTED BOARD ASSEMBLIES –
DESIGN AND USE –
Part 6-4: Land pattern design – Generic requirements for dimensional
drawings of surface mounted components (SMD) from the viewpoint of
land pattern design
1 Scope

This part of IEC 61188 specifies generic requirements for dimensional drawings of SMD from

the viewpoint of land pattern design.

The purpose of this document is to prevent land pattern design issues caused by lack of

information and/or misuse of the information from SMD outline drawing as well as to improve

the utilization of IEC 61188 series.

This document is applicable to the SMD of semiconductor devices and electrical components.

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 60194-2, Printed board design, manufacture and assembly – Vocabulary – Part 2:

Common usage in electronic technologies as well as printed board and electronic assembly

technologies
3 Terms, definitions and symbols

For the purposes of this document, the terms and definitions given in IEC 60194 and IEC

60194-2 apply, and the reference symbols are shown in Table 1.

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
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SIST EN IEC 61188-6-4:2019
IEC 61188-6-4:2019 © IEC 2019 – 7 –
Table 1 – Reference symbols used in this document
Reference Definition
symbol
SMD height (from the mounting surface to the package upper surface)
A Stand-off height (distance from the mounting surface to the package bottom)
A Package height
A Standard heel height for terminal
A Terminal height
A Terminal height (thickness)
A SMD height (from the mounting surface to the package upper surface, maximum)

A SMD height from the mounting surface to the package top (excluding moving part)

A SMD height from the mounting surface to the package top (at the lock lever open state)

A SMD height from the mounting surface to the upper surface of cap
Øb Terminal diameter for ball
Øb Ball diameter
C, C , C Row spacing. Distance between land centers
1 2
CY Courtyard width
CY Courtyard length
D Package width

D Solder balls area width (distance between the centres of the ball of both ends)

E Package length

E Solder balls area length (distance between the centres of the ball of both ends)

E Position of auxiliary terminals
E Upper surface cap width
F , F Clearance between signal and center (GND) terminal
1 2
F Distance from package-end to terminal-end of signal terminal
F Distance between signal terminals at the package corners
G, G , G Distance between lands. Measured from inside edges
1 2
H SMD total width
H SMD total length
H Height from the tray stage to the package top
i Terminal inflection point
J Protrusion length of land over the component terminal
J Heel protrusion length
J Side protrusion length
J Toe protrusion length
k , k k Land pattern length
1 2, 4
k Distance between land patterns
K , K Terminal notch length (toe)
5 6
K , K Terminal notch height (heel)
7 8
L Terminal flat part length (mounting surface side)
L , L Length from the package end to a terminal tip
0 1
L Position of auxiliary terminals
L Auxiliary terminal pitch
L Package length at the lock lever open state
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SIST EN IEC 61188-6-4:2019
– 8 – IEC 61188-6-4:2019 © IEC 2019
Reference Definition
symbol
L Upper surface cap position
L Upper surface cap length
L , L , L Terminal length (mounting surface side),
P P1 P2

Projected terminal length (when part of the terminal is away from the mounting surface)

L Terminal length (upper side)
ØM Diameter of auxiliary terminal
N Coplanarity to mounting surface
P Pitch
q Land pattern design parameter
R Terminal bend radius (inside)
R Terminal bend radius (outside)
S Distance between the terminals. Measured from inside edges
T Tray height from the tray stage to the surface that supports SMD
u , u Allowance for courtyard
1 2
ØW SMD diameter (terminal)
W W Terminal width
1, 2
W Bottom centre (GND) terminal length
W Bottom centre (GND) terminal width
W Groove width
W Position tolerance at terminal end
W Variation range of terminal tip outer position
X Land width
Y Land length
ØY Land diameter
Z Z Z Distance between lands. Measured from outside edges
, 1, 2
α, β (Datum symbols)

η Terminal horizontal angle formed by the groove centre line and the line form the egress to the tip

of the terminal
θ Terminal angle
4 Applicable SMDs
Applicable SMDs are as described below:

a) end-terminal type (components with rectangular or square terminal and cylindrical

components with end cap terminal);

NOTE 1 In IEC 61191-2, "toe" solder fillet height is specified but "heel" solder fillet height is not specified for

this type of SMD.

b) gull-wing terminals type (e.g. SOP, QFP), inward L-shaped ribbon terminals type and

under-body L type (e.g. vertical form aluminium electrolytic capacitor, connector);

NOTE 2 In IEC 61191-2, "heel" solder fillet height is required but "toe" solder fillet height is not required for

these SMD.

c) bottom surface terminal type (e.g. BGA, QFN and LGA) and flat lug terminals type.

NOTE 3 These SMDs have characteristics different from a) or b).
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SIST EN IEC 61188-6-4:2019
IEC 61188-6-4:2019 © IEC 2019 – 9 –
5 Requirements
5.1 Figures and dimensional symbols

The figures shown in this document are indicated as examples of typical SMDs. However, it is

not the purpose to specify the rule of drawings (such as how to pull out a dimension line and

dimensional symbols to be used).

The dimensional symbols in this document are used to show the various cases in order to

indicate common requirements for land pattern designs. This document is not intended to

integrate dimensional symbols.

NOTE The dimensional symbols used in this document are referring to existing International Standards and

industry standards. It is difficult to integrate the dimensional symbols because the definitions of the dimensional

symbols are different between these standards. For this reason, the dimensional symbols in this document can

differ depending on the figure. The dimensional symbols in this document give priority to coordination with land

pattern shape notation given by the IEC 61188-5 series. As a result, the notation for some SMDs can differ from

the industry standards.
5.2 Common requirements
5.2.1 General

The common requirements for dimensional drawings of SMDs from the viewpoint of land

pattern design are described in 5.2.2 to 5.2.10.

To explain a basic relation between dimensional drawings of SMDs and land pattern design, a

representative case is shown in Figure 1 (gull-wing terminals type; 4-pin S-terminals). The

quoted reference symbols in 5.2.2 to 5.2.10 are based on Figure 1.
5.2.2 Requirements for solder joint fillet design

To design a land that is a part of the land pattern and makes a solder joint to each terminal of

the SMD, the dimensional drawing of the SMD shall have the terminal's dimensions (L and

W in Figure 1) and the dimensions that specify the location of the terminal (H and P in

1 E

Figure 1). Each dimension should be indicated by a nominal value with its tolerances.

The reasons are as shown below:
a) As a principle, each terminal of the SMD will have its own land.
Land width (X) and land length (Y) are given by the following formulas:
XW+×2 J
YJ= ++L J
T PH
where
X is the land width [mm];
Y is the land length [mm];
is the terminal width [mm];
L is the terminal length [mm];
J is the toe protrusion length [mm];
J is the heel protrusion length [mm];
J is the side protrusion length [mm].
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SIST EN IEC 61188-6-4:2019
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b) As a principle, the location of each land is decided based on the dimensions, such as H

and P in Figure 1a), which indicate the physical relationship of the soldering terminals of

the SMD.
5.2.3 Requirements for courtyard design

The outermost dimensions of the SMD shall be given (e.g. H , E, D and A in Figure 1). This is

because the courtyard is designed by taking into account the outermost shape after mounting

the SMD on the land pattern.

NOTE The courtyard, which is a monopolization area for the SMD on a PCB, is designed based on the shape of

the mount state (when the SMD is located on the lands), to prevent mechanical interferences at the time of

mounting or assembly. If solder paste openings are outside the maximum extent of the package outline, plus

terminals plus lands, the court
...

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