IPC-CM-770D-1996.pdf - 第23页

January 1996 IPC-CM-770 enhance the interconnection capabilities and to interface with housings, supports, test equipment and other periph- eral structures. The details of these special components are contained in Sectio…

IPC-CM-770

Januaty

1996

4.1 Discrete Axial-Leaded Components

Discrete axial-

leaded devices are two-leaded board mounted components

that have the leads exiting from the ends of the component

along the axis of the components. They are considered suit-

able for automatic component insertion. The most common

axial-leaded devices are resistors, capacitors and diodes.

Detailed description of axial leaded components in con-

tained in Section

4.2 Discrete Radial-Leaded Components

Discrete

radial-leaded devices are two-leaded board mounted com-

ponents that have all of the leads exiting from one side of

the component. Sometimes this side is on the perimeter of

the package and sometimes it is the bottom of the compo-

nent.

The body shapes vary from simple disc-shaped capacitors

to transistor-outline “TO” package high power transistors.

Details of radial-leaded components are contained in Sec-

tion 6.

4.3 Chip Components

Chip components comprise a

wide variety of two-terminal devices for surface mount

attachment. Some of the chip components have formed

metal leads for attachment but most are simple ceramic

devices with plated or solder dipped terminations that are

integral with the body of the component, chip components

are small and are designed and packaged for automatic

component handling. The details of chip components are

contained in Section 7.

4.4 Multileaded-Radial Components

Multileaded radial

components are assembled components that have all of the

leads exiting from one side of the component or from the

perimeter of the component base. Generally active semi-

conductor devices or arrays of two terminal devices can be

packaged in multileaded radial configurations. The details

of multileaded radial components are contained in Section

4.5 Small Outline Components

Small outline compo-

nents (SOTS) are a family of three- or four-lead plastic

post-molded components intended for surface mount

attachment. Small outline integrated circuits (SolCs) com-

prise a family of multileaded surface mount components

that have two rows of formed leads on

5.08

mm centers.

Details of

“SO”

components are contained in Section

4.6 ln-Line-Lead Components

This class of components

includes the traditional through board mounted components

that have the leads arrayed in one or more rows of formed

metal leads spaced on 2.54 mm centers. The body configu-

rations are variable but most of them are designed for

assembly with automatic machinery. The details of dual-

inline (DIP) and single-inline (SIP) packages are contained

in Section

10.

4.7 Multiple-Ribbon-Lead Components

Ribbon-leaded

components have flat wire ribbon leads that are arrayed

around the perimeter of the component. They are fre-

quently used to package high density integrated circuits

with special electrical requirements. Ribbon-leaded compo-

nent details are contained in Section

11.

4.8 Chip Carriers

Chip carriers are currently the most

common multileaded surface mount package. Their termi-

nations are arrayed around the perimeter of the rectangular

body and can be in the form of either formed metal leads

or pads that are integral to the body of the component. For

printed board mounting most chip carrier leads are located

on 1.27 mm centers but newer designs are considering

0.635 mm and smaller spacings between leads. The small

lead spacing and the large number of leads can require

special assembly procedures. Chip carrier package details

are contained in Section 12.

4.9 Pin Grid Arrays

Pin grid arrays form a class of very

high inputloutput (I/O) through board mount integrated cir-

cuit package. The leads are arranged in a solid area-filling

array across the bottom of the package, frequently with

space left free under the chip mount area. Details of pin

grid array packages are contained in Section 13.

4.1

Unpackaged Semiconductors

This type of compo-

nent includes all semiconductor devices that are not in indi-

vidual discrete packages. They may consist of individual

semiconductor dice that have termination bonding pads or

they may be semiconductor dice bonded to flexible sub-

strates, such as TAB, to aid in their handling and intercon-

nection. These components are used primarily with chip-

on-board technology as described in Section 14.

4.1 1 Connectors

Connectors form the means to inter-

connect between a printed board structure and another level

of interconnection with a separable connection. Connectors

between printed wiring boards and cables, backplanes and

special printed board structures are common. Frequently

connectors consist of a molded plastic housing that con-

tains formed metal contacts. Connectors can be either

through board or surface mount assembled. Connector

details are contained in Section

15.

4.12 Sockets

A socket is a form of connector used to

make separable contact between a printed board structure

and the terminations (leads) of a component. Sockets are

frequently assembled with the same technologies used for

components. Details of sockets are contained in Section 16.

4.1 3 Electromechanical and Interconnect Compo-

nents

Other board mounted components, such as pins,

wires, terminals, and mechanical hardware comprise a wide

set of parts that are assembled to printed wiring products to

1-8

Licensed by Information Handling Services

January

1996

IPC-CM-770

enhance the interconnection capabilities and to interface

with housings, supports, test equipment and other periph-

eral structures. The details of these special components are

contained in Sections

16,

and

18.

4.1 4 Packaging and Interconnecting (Printed Board)

Structures

Printed board structures include conventional

and modified organic printed boards, inorganic ceramic

printed boards, and supporting planekore structures.

Details concerning printed board structures are described in

Section

19.

4.1

TAB

Tape Automated Bonding (TAB) involves the

automated bonding of semiconductor devices (dies) to a

flexible lead frame in tape and reel format. The devices are

delivered to the assembly operation on tape where the indi-

vidual devices and part of the interconnecting lead frame

are excised, the leads formed and the devices directly

mounted to a printed board structure. TAB devices are fre-

quently encapsulated after mounting to the printed board

structure. Details are contained in Section

24.

4.16 Pad Grid Arrays

Pad Grid Arrays, also known as

Land Grid Arrays are surface mount packages where the

interconnections are distributed in an area array on the bot-

tom of the package. The interconnections are typically sol-

der columns connecting lands on the bottom of the pack-

age to a matching set of lands on a printed board structure

beneath it. Details of Pad Grid Arrays are contained in

Section

13.

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IPC-CM-770

Januaty

1996

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