Printed boards and printed board assemblies - Design and use - Part 7: Electronic component zero orientation for CAD library construction

IEC 61188-7:2017 establishes a consistent technique for the description of electronic component orientation, and their land pattern geometries. This facilitates and encourages a common data capture and transfer methodology amongst and between global trading partners.
This edition includes the following significant technical changes with respect to the previous edition:
a) Figure 1 has been corrected;
b) the term “rectangle” has generally been replaced by “polygon”;
c) level B has been indicated as preferred level for new libraries.

Cartes imprimées et cartes imprimées équipées - Conception et utilisation - Partie 7: Orientation nulle des composants électroniques pour l'élaboration d’une bibliothèque CAO

L’IEC 61188-7:2017 établit une technique cohérente pour décrire l’orientation des composants électroniques, ainsi que les géométries de leurs zones de report. Cela facilite et encourage une méthodologie commune de saisie et de transfert des données parmi et entre les partenaires commerciaux mondiaux.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) la Figure 1 a été corrigée;
b) le terme “ rectangle “ a été généralement remplacé par “ polygone “;
c) le niveau B a été indiqué comme niveau à privilégier pour les nouvelles bibliothèques.

General Information

Status
Published
Publication Date
09-Apr-2017
Current Stage
PPUB - Publication issued
Start Date
10-Apr-2017
Completion Date
10-Apr-2017
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IEC 61188-7
Edition 2.0 2017-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Printed boards and printed board assemblies – Design and use –
Part 7: Electronic component zero orientation for CAD library construction
Cartes imprimées et cartes imprimées équipées – Conception et utilisation –
Partie 7: Orientation nulle des composants électroniques pour l’élaboration
d’une bibliothèque CAO
IEC 61188-7:2017-04(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61188-7
Edition 2.0 2017-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Printed boards and printed board assemblies – Design and use –
Part 7: Electronic component zero orientation for CAD library construction
Cartes imprimées et cartes imprimées équipées – Conception et utilisation –
Partie 7: Orientation nulle des composants électroniques pour l’élaboration
d’une bibliothèque CAO
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180 ISBN 978-2-8322-7388-3

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
---------------------- Page: 3 ----------------------
– 2 – IEC 61188-7:2017  IEC 2017
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

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

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

3 Terms and definitions ...................................................................................................... 6

4 Basic rules ...................................................................................................................... 6

4.1 Common rules......................................................................................................... 6

4.2 General basic rules ................................................................................................. 6

4.3 Level A basic rule ................................................................................................... 7

4.4 Level B basic rule ................................................................................................... 7

4.5 File description definition ........................................................................................ 7

4.6 Component orientations .......................................................................................... 8

5 Origin point of land pattern ............................................................................................ 18

5.1 General ................................................................................................................. 18

5.2 Surface mount components ................................................................................... 18

5.3 Through-hole leaded components ......................................................................... 19

6 Land pattern to footprint comparison ............................................................................. 20

7 Components with one terminal ....................................................................................... 20

7.1 Surface mount components ................................................................................... 20

7.2 Through-hole leaded components ......................................................................... 20

Figure 1 – Example of level A orientation concepts ................................................................. 8

Figure 2 – Connector and switch library symbol examples .................................................... 19

Figure 3 – Through-hole components with terminal point of origin orientation ....................... 19

Figure 4 – Circular or square one-terminal component .......................................................... 20

Figure 5 – Rectangular or oval one-terminal component ....................................................... 20

Figure 6 – Surface mount components with one lead offset ................................................... 20

Table 1 – Discrete component land pattern conventions ......................................................... 9

Table 2 – Diode and transistor land pattern conventions ....................................................... 10

Table 3 – Transistor and IC land pattern conventions ........................................................... 11

Table 4 – Integrated circuit packages land pattern conventions ............................................ 12

Table 5 – Integrated circuit packages land pattern conventions ............................................ 14

Table 6 – BGA land pattern conventions ............................................................................... 15

Table 7 – Resistor array and connector land pattern conventions.......................................... 16

Table 8 – Level A land pattern convention summary ............................................................. 17

Table 9 – Level B land pattern convention summary ............................................................. 18

---------------------- Page: 4 ----------------------
IEC 61188-7:2017  IEC 2017 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED BOARDS AND PRINTED BOARD ASSEMBLIES –
DESIGN AND USE –
Part 7: Electronic component zero orientation
for CAD library construction
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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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 61188-7 has been prepared by IEC technical committee 91:

Electronics assembly technology.

This bilingual version (2019-09) corresponds to the monolingual English version, published in

2017-04.

This second edition cancels and replaces the first edition published in 2009. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
a) Figure 1 has been corrected;
b) the term “rectangle” has generally been replaced by “polygon”;
---------------------- Page: 5 ----------------------
– 4 – IEC 61188-7:2017  IEC 2017
c) level B has been indicated as preferred level for new libraries.
The text of this International Standard is based on the following documents:
CDV Report on voting
91/1382/CDV 91/1428/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.
The French version of this standard has not been voted upon.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of the IEC 61188 series, 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.
---------------------- Page: 6 ----------------------
IEC 61188-7:2017  IEC 2017 – 5 –
INTRODUCTION

One of the factors of establishing a CAD library component description and land pattern

standard is to adopt a fixed zero component orientation so that all CAD images are built with

the same rotation for the purpose of assembly machine automation.

The land pattern standards clearly define all the properties necessary for standardization and

acceptability of a one world CAD library. The main objective in defining a one world CAD

library is to achieve the highest level of electronic product development automation. This

encompasses all the processes involved from engineering to PCB layout to fabrication,

assembly and test. The data format standards need this type of consistency in order to meet

the efficiency that electronic data transfer can bring to the industry.

Many large firms have spent millions of dollars creating and implementing their own unique

standards for their own electronic product development automation. These standards are

proprietary to each firm and are not openly shared with the rest of the industry. This has

resulted in massive duplication of effort, costing the industry millions of man hours in waste

and creating industry chaos and global non-standardization.

The main purpose of creating the land pattern standards is to achieve reliable solder joint

formation platforms; the reason for developing the data transfer structure is to improve the

efficiency with which engineering intelligence is converted into manufacturing reality. Even if

the neutral CAD format can drive all the manufacturing machines, it would be meaningless

unless the component description standard for CAD land patterns were implemented with

some consistency. Zero component orientation has a key role in machine automation.

The obvious choice for global standardization for EE hardware engineering, PCB design

layout, manufacturing, assembly and testing processes is to incorporate the standard land

pattern conventions. Any other option continues the confusion and additional manual hours of

intervention in order to achieve the goals of automation. In addition, the ease of having one

system export a file so that another system can accomplish the work can require unnecessary

manipulation of the neutral format in order to meet the object of clear, unambiguous software

code.

The design of any assembly will continue to permit arrangement and orientation of

components at any orientation consistent with design standards. Starting from a commonly

understood data capture concept will benefit the entire supply chain.

This standard defines angle and origin point of land patterns for land pattern designing.

---------------------- Page: 7 ----------------------
– 6 – IEC 61188-7:2017  IEC 2017
PRINTED BOARDS AND PRINTED BOARD ASSEMBLIES –
DESIGN AND USE –
Part 7: Electronic component zero orientation
for CAD library construction
1 Scope

This part of IEC 61188 establishes a consistent technique for the description of electronic

component orientation, and their land pattern geometries. This facilitates and encourages a

common data capture and transfer methodology amongst and between global trading partners.

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 61188-5 (all parts), Printed boards and printed board assemblies – Design and use – Part

5-x: Attachment (land/joint) considerations
3 Terms and definitions
No terms and definitions are listed in this document.

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 Basic rules
4.1 Common rules

Common rules are divided into two groups: level A and level B. The main difference between

the rules is the original orientation within the CAD system library. This orientation may be any

version that the designer finds useful including his own version; however, when the

information is transferred to an assembler, the orientation shall be properly defined without

ambiguity or shall be corrected in order that any variation between the different systems are

properly matched. This conversion of the CAD data to manufacturing information may include

the datum of the board, fabrication panel or assembly array panel and shall have the proper

orientation of all components on the board no matter what library was used as the original

input.
4.2 General basic rules
The following basic rules apply.
• Components and land patterns are drawn in top view.
• The component point of origin is shown by "+" or "x".
---------------------- Page: 8 ----------------------
IEC 61188-7:2017  IEC 2017 – 7 –

• The origin point of land patterns may be different from the origin point of the placement.

• A polygon that contains the component body and land patterns (in top view) should be a

part of the library component description. This rectangle is the courtyard that provides a

minimum electrical and physical clearance for the part and the land pattern. The point of

origin of the description should match that of the component and land pattern.

• The arrangement of land-patterns is fixed uniformly by the classification and the shape of

components and shall be as described in IEC 61188-5-1 to IEC 61188-5-8. The

information for the land-patterns is independent from the angle in the component delivery

system (tape, tray, tube, etc.). The location of pin one in the land pattern or component

description shall be identical with any polarization mark on the component. If other

descriptions are used on the component data (e.g. cathode, anode, base, emitter,

collector), the library description shall assign an appropriate pin one designation.

• The component orientation shall position pin one as being on the left-hand side of the

component description.

• The component, land pattern and polygon area shall be identical in the computer library

with each description using the same point of origin coordinates. It is recommended that

the point of origin is the same as the way the component is positioned on the final design

of the board, which is normally by the centroid of the component body. Only the

component rotation shall be altered to match the rules for level A or level B descriptions

for components with more than two pins.
4.3 Level A basic rule
For level A, the following basic rule applies.

• For level A type component descriptions for multiple leaded parts, pin one shall be left

oriented as indicated in the basic rules; however, pin one shall be located at the upper or

upper-left position.
4.4 Level B basic rule
For level B, the following basic rule applies.

• For level B type component descriptions for multiple leaded parts, pin one shall be left

oriented as per the basic rules; however, pin one shall be located at the left or lower-left

position.
4.5 File description definition

Since the basic rules allow two variations of levels in the description of the CAD system

library, it is a mandatory requirement to define which level was used (level A or Level B) for

the component descriptions in the data file. This information is a mandatory requirement in

the header of any file that incorporates land patterns using these principles of zero-based

orientation. See Figure 1.
---------------------- Page: 9 ----------------------
– 8 – IEC 61188-7:2017  IEC 2017
0° orientation
Mirror image
90° orientation
Mirror image
180° orientation
Mirror image
270° orientation
Mirror image
IEC
Figure 1 – Example of level A orientation concepts
4.6 Component orientations

The zero component orientations expressed in this document are defined in terms of the

standard component CAD library with respect to a given PCB design. Recognizing that a

single land pattern may be used for the same component part from different suppliers and that

each component supplier can have different orientations on their reels or that the components

can come in trays, there exists the possibility that the PCB designer loses the ability to

reference a single land pattern if the zero rotation of a part is according to the method in

which the component is delivered to the assembly machine.

Since the CAD library contains a single land pattern, the zero component rotation is thus

defined according to the CAD library. Subsequently, component suppliers can identify the

orientation of the parts on the reels by associating the placement of the part on the reel to

zero orientations defined in this document. If pin one is at the lower left as defined by the pick

and place machine tape and reel, for example, then the component on the reel is rotated 90°

---------------------- Page: 10 ----------------------
IEC 61188-7:2017  IEC 2017 – 9 –

counterclockwise from the zero rotation given in this document. Standardizing the orientation

of components for the installation and usage of various packaging methods, such as tubes,

trays or tapes and reels, among the variations of automated assembly equipment in existence

today is outside the scope of this document.

Table 1 to Table 7 show zero component rotations using the basic rules and rules for level A

and level B component descriptions. For new CAD libraries, level B should be used as the

preferred orientation.
Table 1 – Discrete component land pattern conventions
Package type Component example Level A Level B
Chip capacitor
Chip resistor
Chip inductor
Molded capacitor
Molded diode
---------------------- Page: 11 ----------------------
– 10 – IEC 61188-7:2017  IEC 2017
Package type Component example Level A Level B
Molded inductor
Precision
wirewound
Table 2 – Diode and transistor land pattern conventions
Package type Component example Level A Level B
Diode (MELF)
Resistor (MELF)
Aluminium
electrolytic
capacitor
SOT23-3
---------------------- Page: 12 ----------------------
IEC 61188-7:2017  IEC 2017 – 11 –
Package type Component example Level A Level B
SOT23-5
SOT343
SOT223
Table 3 – Transistor and IC land pattern conventions
Package type Component example Level A Level B
TO252 (DPAK)
SOIC, SOP, and
SSOP
TSSOP
---------------------- Page: 13 ----------------------
– 12 – IEC 61188-7:2017  IEC 2017
Package type Component example Level A Level B
SOJ
Square QFP,
pin one in
corner
Rectangular
QFP, pin one in
corner
Table 4 – Integrated circuit packages land pattern conventions
Package Component example Level A Level B
type
Bump QFP,
pin one in
corner
---------------------- Page: 14 ----------------------
IEC 61188-7:2017  IEC 2017 – 13 –
Package Component example Level A Level B
type
Bump QFP,
pin one in
middle
Ceramic flat
package
CQFP
(ceramic
quad flat
package)
PLCC (QFJ)
square
J leaded,
pin one in
middle
---------------------- Page: 15 ----------------------
– 14 – IEC 61188-7:2017  IEC 2017
Table 5 – Integrated circuit packages land pattern conventions
Package type Component example Level A Level B
PLCC (QFJ)
rectangular
J leaded
pin one in
middle
LCC square
pin one in
middle
QFN square
QFN
rectangular
---------------------- Page: 16 ----------------------
IEC 61188-7:2017  IEC 2017 – 15 –
Table 6 – BGA land pattern conventions
Package Component example Level A Level B
type
BGA
square
BGA
rectangular
---------------------- Page: 17 ----------------------
– 16 – IEC 61188-7:2017  IEC 2017
Table 7 – Resistor array and connector land pattern conventions
Package Component example Level A Level B
type
Resistor
array
SMT
connector
Pin 1
Pin 1

Table 8 provides a summary of the land pattern conventions for level A library concepts.

---------------------- Page: 18 ----------------------
IEC 61188-7:2017  IEC 2017 – 17 –
Table 8 – Level A land pattern convention summary
Level A summary – Component marking identifies pin one of land pattern

1) Chip capacitors, resistors and inductors (RES, CAP and IND) – Pin one of land pattern on left

2) Molded Inductors (INDM), resistors (RESM) and tantalum capacitors (CAPT) – Pin one of land pattern on

left
3) Precision wire-wound Inductors (INDP) – Pin one of land pattern on left
4) MELF diodes – Pin one of land pattern on left
5) Aluminium electrolytic capacitors (CAPAE) – Pin one of land pattern on left

6) SOT Devices (SOT23, SOT23-5, SOT223, SOT89, SOT143, etc.) – Pin one of land pattern on upper left

7) TO252 & TO263 (DPAK Type) devices – Pin one of land pattern on upper left

8) Small outline gullwing ICs (SOIC, SOP, TSOP, SSOP, TSSOP) – Pin one of land pattern on upper left

9) Ceramic flat packs (CFP) – Pin one of land pattern on upper left
10) Small outline J lead ICs (SOJ) – Pin one of land pattern on upper left
11) Quad flat pack ICs (PQFP, SQFP) – Pin one of land pattern on upper left
12) Ceramic quad flat packs (CQFP) – Pin one of land pattern on upper left
13) Bum
...

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