IPC-CM-770D-1996 - 第43页

January 1996 IPC-CM-770 i I I l I I I L 'I t-"I t T SOT 23 t"i SOT 89 IPC-I- Typical SOT Packages into a 10+5" vee provide retention of the component. (See Figure 10- 1 .) 10.1.2 Single-lnline Package…

IPC-CM-770

Januaty

1996

view

040 150

L-

o12

SO-16

(INCHES

SHOWN)

IPC-1.00375

Figure 9-1 SO-1 6 Package Drawings Typical Dimension

9.1.3 Outlines

package are included in JEDEC

95-83.

9.2 Through-Hole Mounting

devices are not

designed for through-hole mounting.

9.3 Surface Mounting

9.3.1 Component Preparation

devices are supplied

by the manufacturers preformed for surface mounting.

Lead configurations are illustrated in Figures 9-1 and 9-2.

9.3.2 Land Patterns

Land pattern configurations for

small outline packages are provided in IPC-SM-782.

The SOT-23 package is the most common three leaded sur-

face mount device configuration. SO-89 packages are used

for high power devices where heat transfer to the support-

ing printed board is important.

With an SOT-23, the single land on one side of the pack-

age can be enlarged when reflow soldering is used,

that

the solder-lead surface tension is more nearly balanced.

When wave soldering is used the parts are held onto the

board with an adhesive and the surface tension balance is

not important.

9.3.3 LeadlLand Configuration After Assembly

devices may be mounted with or without adhesive.

adhe-

sive is used to secure the

package to the substrate,

major considerations are:

The adhesive must not contaminate the land area.

The adhesive must be cured prior to soldering

9.3.4 Mounted Component Configurations

Applicable

guidelines are included in Section 22.

9.4 Mixed Technology

Higher count

devices are nor-

mally mounted on the component side of the substrate

while the small SOT devices can be found on both sides.

Therefore, the guidelines of Section 25 are the usual

method of fabrication when the assembly uses both

devices and through-the-board mounted devices.

9.5 Manual Assembly

Manual techniques for assembly

using

devices are included in Section 22.

9.6 Automated Assembly

Automated techniques for

assembly using

devices are included in Section 22.

9.7 Handling and Storage

The handling and storage of

small-outline components should be in accordance with the

guidelines of Section 26.

9.8 Soldering

General soldering techniques applying to

all types of components are described in Section 27.

9.9 Cleaning

General techniques for cleaning applying

to all types of components are described in Section 28.

9.1

Conformal Coating

General techniques for confor-

mal coating for all types of assemblies are described in

Section 29.

10.0 INLINE-LEAD COMPONENTS

10.1

Part Type Description

10.1.1 Dual-lnline Packages

The dual inline multiple-

lead component (DIP) has its lead pointing downward

ready for insertion into holes in a printed board.

The dual inline package can be inserted easily, either auto-

matically or manually. Sockets are available for mounting

and testing purposes. Automatic insertion is very feasible

using this package configuration.

A DIP is made of metal, ceramic, glass, plastic, or combi-

nations of these materials. Leads, body, and glass sealing

are designed to make this a rugged package. Lead configu-

ration (shoulder) provides a standoff feature. Leads formed

3-6

Licensed by Information Handling Services

January

1996

IPC-CM-770

t-"I

SOT

t"i

SOT

IPC-I-

Typical SOT Packages

into a

10+5"

vee provide retention of the component. (See

Figure

10-

10.1.2 Single-lnline Packages

The single inline (SIP)

components are similar to the dual inline (DIP) compo-

nents with leads that exit the component body "in-line"

2.54

mm apart center to center, but in a single row pattern

rather that the dual row (square) pattern of the DIP (see

Figure

10-2).

Single inline (SIP) component configuration is usually

associated with resistor networks and can therefore reduce

handling, inventory, and assembly require- ments by the

use of a single component, versus a number of discrete

components. Advantageous use of the SIP type component

are applications where printed board real estate is limited.

10.2 Through-Hole Mounting

10.2.1 Component Preparation

SIP components are

ready for manual insertion without the use of special tools

or fixtures. Lead preparation is not normally required. Lead

clinching is required for component retention on board

through manufacturing operations. Standoffs are usually

built-in to the component body to accomplish proper board

spacing as shown in the typical SIP specification in Figure

10-2.

For DIP packages (whether lands are of a round,

square or ribbon across section) leads should be dressed to

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IPC-CM-770

Januaty

1996

110.16

mm1

[.400"] max

2.54

OO"]

max

.25

[.O1

O"]

non

accum

IPC-I-O0042

Figure 10-1 16-Lead DIP

IPC-1-00373

Figure 10-2 Single In-line Component

and through the printed board such that deformation does

not cause clearance spacings to be reduced beyond the

minimum. Slanting, bowing and bending of leads in any

direction should not exceed

of the lead width (or diam-

eter) nor should leads be twisted more than

15".

10.2.2 Land Patterns

DIP layouts usually follow a rect-

angular grid pattern and reasonable densities are possible,

such as that shown in Figure

10-3.

10.2.3 Lead Configuration After Assembly

The maxi-

mum clinched lead length is dependent upon the length of

lead that is available for cutting and clinching and the

thickness of the printed board.

nominal clinched lead

ength is

1.25

mm although a range from

0.75

mm mini-

mum to

2.25

mm maximum is attainable. In all cases the

land diameter should be large enough to accommodate the

clinched lead to minimize solder bridging. (See Figure

10-4.)

minimum of two

(2)

diagonally opposite leads should be

clinched for part retention as shown in Figure

10-4.

10.2.4 Mounted Configuration

The base of the device

should be parallel to the surface of the printed board to the

All

lines 0.3

[0.012]

Plated hole

1.0 [0.040]

All

line spacing 0.2 [0.010]

Lands 1.5 [0.06]

Component centers 12.5 [0.5]

22.5 [0.9]

Component area 19.6 [0.785]

8.3 [0.332]

........

9 lines 7.5 10.31

lin es^^^^^^

-5 lines 5.0 [0.2]

........*

5.0 [0.2]--1 200

IPC-1-00169

Figure 10-3 A Typical Dual In-line Layout

View

IPC-I-O0201

Figure 10-4 Lead Configuration (After Assembly)

extent that minimum lead protrusion and maximum com-

ponent body height from the board is maintained (see IPC-

A-610).

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