IPC-SM-782A 表面安装设计和焊盘设计标准(带BGA).pdf - 第104页

4.0 COMPONENT DIMENSIONS Figure 2 provides the component dimensions for SOT 143 components. Component Identiﬁer L (mm) S (mm) W1 (mm) W2 (mm) T (mm) P1 (mm) P2 (mm) H (mm) min max min max min max min max min max basic ba…

1.0 SCOPE

This subsection provides the component and land pattern

dimensions for SOT 143 (small outline transistor) components.

Basic construction of the SOT 143 device is also covered. At

the end of this subsection is a listing of the tolerances and

target solder joint dimensions used to arrive at the land pat-

tern dimensions.

2.0 APPLICABLE DOCUMENTS

See Section 8.0 for documents applicable to the subsections.

2.1 Electronic Industries Association (EIA)

JEDEC Pub-

lication 95 Registered and Standard Outlines for Solid State

and Related Products, TO-253, Issue ‘‘C’’ dated 11/14/90

Application for copies should be addressed to:

Global Engineering Documents

1990 M Street N.W.

Washington, DC

3.0 COMPONENT DESCRIPTIONS

These parts are for dual diodes and Darlington transistors.

3.1 Basic Construction

See Figure 1. The dimensional

characteristics are designed to meet the needs of the surface

mount industry. The clearance between the body of the com-

ponent and the packaging and interconnect structure is speci-

fied at 0.05 to 0.13 mm [0.002 to 0.005 in] to accommodate

reflow or wave soldering processes.

3.1.1 Termination Materials

Leads must be solder-

coated with a tin/lead alloy. The solder should contain

between 58 to 68% tin. Solder may be applied to the leads by

hot dipping or by plating from solution. Plated solder termina-

tions should be subjected to post-plating reflow operation to

fuse the solder. The tin/lead finish should be at least 0.0075

mm [0.0003 in] thick.

Solder finish applied over precious metal electrodes should

have a diffusion barrier layer between the electrode metalliza-

tion and the solder finish. The barrier layer should be nickel or

an equivalent diffusion barrier, and should be at least 0.00125

mm [0.00005 in] thick.

3.1.2 Marking

Parts are available with or without marked

values.

3.1.3 Carrier Package Format

Carrier package format

shall be according to the following: body type TO-253, 8 mm

tape/4 mm pitch.

3.1.4 Resistance to Soldering

Parts should be capable of

withstanding five cycles through a standard reflow system

operating at 215°C. Each cycle shall consist of 60 seconds

exposure at 215°C. Parts must also be capable of withstand-

ing a minimum of 10 seconds immersion in molten solder at

260°C.

IPC-782-8-9-1

Figure 1 SOT 143 construction

IPC-SM-782

Surface Mount Design

and Land Pattern Standard

Date

8/93

Section

8.9

Revision Subject

SOT 143

Page1of4

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4.0 COMPONENT DIMENSIONS

Figure 2 provides the component dimensions for SOT 143 components.

Component

Identiﬁer

L (mm) S (mm) W1 (mm) W2 (mm) T (mm)

(mm)

min max min max min max min max min max basic basic max

SOT 143 2.10 2.64 1.00 1.69 0.37 0.46 0.76 0.89 0.25 0.55 1.92 1.72 1.20

Figure 2 SOT 143 component dimensions

▼

▼▼

1.20–1.40

2.80–3.04

▼

0.85–0.130

▼

IPC-782-8-9-2

IPC-SM-782

Subject

SOT 143

Date

8/93

Section

8.9

Revision

Page2of4

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5.0 LAND PATTERN DIMENSIONS

Figure 3 provides the land pattern dimensions for SOT 143

components. These numbers represent industry consensus

on the best dimensions based on empirical knowledge of fab-

ricated land patterns.

In the table, the dimensions shown are at maximum material

condition (MMC). The least material condition (LMC) should

not exceed the fabrication (F) allowance shown on page 4.

The LMC and the MMC provide the limits for each dimension.

The dotted line in Figure 3 shows the grid placement court-

yard which is the area required to place land patterns and

their respective components in adjacent proximity without

interference or shorting. Numbers in the table represent the

number of grid elements (each element is 0.5 by 0.5 mm) in

accordance with the international grid detailed in IEC publica-

tion 97.

RLP No.

Component

Identiﬁer Z (mm) G (mm) X1 (mm)

X2 (mm) C E1 E2 Y

Placement

Grid (No.

of Grid

elements)min max ref Basic Basic ref

225 SOT 143 3.60 0.80 1.00 1.00 1.20 2.20 1.90 1.70 1.40 8x8

Figure 3 SOT 143 land pattern dimensions

▼

X1X2

Grid

Placement

Courtyard

▼

IPC-782-8-9-3

IPC-SM-782

Subject

SOT 143

Date

8/93

Section

8.9

Revision

Page3of4

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