IPC-SM-782A-表面贴装焊盘图形设计标准.pdf.pdf - 第182页

4.0 COMPONENT DIMENSIONS Figure 2 provides the component dimensions for LCC components. Component Identiﬁer T ype L (mm) S (mm) W (mm) T1 (mm) T2 (mm) H (mm) P (mm) min max min max min max min max m in max max basic LCC-…

1.0 SCOPE

This subsection provides the component and land pattern

dimensions for leadless ceramic chip carriers (LCC compo-

nents). Basic construction of the LCC 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 12.0 and the following for documents applicable

to this subsection.

2.1 Electronic Industries Association (EIA)

JEDEC Publication 95

Registered and Standard Outlines for Solid JEDEC Publication

95 State and Related Products, ‘‘0.050 In. Center, Leadless

Type A,’’ Outline MS002, issue ‘‘A,’’ dated 9/29/80, and

‘‘0.050 In. Center, Leadless Type C,’’ Outline MS004, issue

‘‘B,’’ dated 5/90

3.0 Component Descriptions

3.1 Basic Construction

A leadless chip carrier is a

ceramic package with integral surface-metallized terminations.

Leadless Types A, B, and D chip carriers have a chamfered

index corner that is larger than that of Type C. Another differ-

ence between the A, B, and D types and Type C is the fea-

ture in the other three corners. The types A, B, and D, were

designed for socket applications and printed wiring intercon-

nections. The Type C is primarily intended for direct attach-

ment through reflow soldering. This application difference is

the main reason for their mechanical differences. These pack-

ages mount in different orientations, depending on type,

mounting structure and preferred thermal orientation.

Leadless Type A is intended for lid-down mounting in a

socket, which places the primary heat-dissipating surface

away from the mounting surface for more effective cooling in

air-cooled systems.

Type C is a ceramic package similar to leadless Type B

except for corner configuration. The 50 mil center family,

which includes both leadless and leaded devices, is designed

to mount on a common mounting pattern. They may be

directly attached to the mounting structure, or can be plugged

into sockets. One basic restriction is that there shall be no

terminals in the corners of the package. There are a number

of common sizes.

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.

3.1.2 Marking All parts shall be marked with a part num-

ber and ‘‘Pin 1’’ location. Pin 1 location may be molded into

the plastic body.

3.1.3 Carrier Package Format Tube carriers are preferred

for best handling.

3.1.4 Process Considerations LCCs are usually pro-

cessed using standard solder reflow processes. Parts should

be capable of withstanding ten cycles through a standard

reflow system operating at 215°C. Each cycle shall consist of

60 seconds exposure at 215°C.

IPC-782-12-3-1

Figure 1 LCC Construction

IPC-SM-782

Surface Mount Design

and Land Pattern Standard

Date

8/93

Section

12.3

Revision Subject

LCC

Page1of4

4.0 COMPONENT DIMENSIONS

Figure 2 provides the component dimensions for LCC components.

Component

Identiﬁer Type

L (mm) S (mm) W (mm) T1 (mm) T2 (mm)

(mm)

min max min max min max min max m in max max basic

LCC-16 Type C 7.42 7.82 4.64 5.16 0.56 1.04 1.15 1.39 1.96 2.36 2.54 1.27

LCC-20 Type C 8.69 9.09 5.91 6.43 0.56 1.04 1.15 1.39 1.96 2.36 2.54 1.27

LCC-24 Type C 10.04 10.41 7.26 7.76 0.56 1.04 1.15 1.39 1.96 2.36 2.54 1.27

LCC-28 Type C 11.23 11.63 8.45 8.97 0.56 1.04 1.15 1.39 1.96 2.36 2.54 1.27

LCC-44 Type C 16.26 16.76 13.48 14.08 0.56 1.04 1.15 1.39 1.96 2.36 3.04 1.27

LCC-52 Type C 18.78 19.32 16.00 16.64 0.56 1.04 1.15 1.39 1.96 2.36 3.04 1.27

LCC-68 Type C 23.83 24.43 21.05 21.74 0.56 1.04 1.15 1.39 1.96 2.36 3.04 1.27

LCC-84 Type C 28.83 29.59 26.05 26.88 0.56 1.04 1.15 1.39 1.96 2.36 3.04 1.27

LCC-100 Type A 34.02 34.56 31.24 31.88 0.56 1.04 1.15 1.39 1.96 2.36 4.06 1.27

LCC-124 Type A 41.64 42.18 38.86 39.50 0.56 1.04 1.15 1.39 1.96 2.36 4.06 1.27

LCC-156 Type A 51.80 52.34 49.02 49.66 0.56 1.04 1.15 1.39 1.96 2.36 4.06 1.27

Figure 2 LCC component dimensions

▼

Note: Component body Widths normally described as “A” & “B” on other components are equal to “L”.

▼

IPC-782-12-3-2

IPC-SM-782

Subject

LCC

Date

8/93

Section

12.3

Revision

Page2of4

5.0 LAND PATTERN DIMENSIONS

Figure 3 provides the land pattern dimensions for LCC com-

ponents. These numbers represent industry consensus on the

best dimensions based on empirical knowledge of fabricated

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) X (mm)

(mm)

(mm) C (mm) D (mm) E (mm)

Placement Grid

(No. of Grid

Elements)ref ref ref ref ref

830 LCC-16 9.80 4.60 0.80 2.60 3.40 7.20 3.81 1.27 22X22

831 LCC-20 11.00 5.80 0.80 2.60 3.40 8.40 5.08 1.27 24X24

832 LCC-24 12.40 7.20 0.80 2.60 3.40 9.80 6.35 1.27 26X26

833 LCC-28 13.60 8.40 0.80 2.60 3.40 11.00 7.62 1.27 30X30

834 LCC-44 18.80 13.60 0.80 2.60 3.40 16.20 12.70 1.27 40X40

835 LCC-52 21.20 16.00 0.80 2.60 3.40 18.60 15.24 1.27 44X44

836 LCC-68 26.20 21.00 0.80 2.60 3.40 23.60 20.32 1.27 54X54

837 LCC-84 31.40 26.20 0.80 2.60 3.40 28.80 25.40 1.27 64X64

838 LCC-100 36.40 31.20 0.80 2.60 3.40 33.80 30.48 1.27 74X74

839 LCC-124 44.20 39.00 0.80 2.60 3.40 41.60 38.10 1.27 90X90

840 LCC-156 54.20 49.00 0.80 2.60 3.40 51.60 48.26 1.27 110X110

Figure 3 LCC land pattern dimensions

▼

Pin 2

Pin 1

▼

Full radius

optional

▼

1.00 MIN.

1.10 NOM.

1.20 MAX.

.10 MIN.

.20 NOM.

.40 MAX.

▼

Contact

metallization

▼

Grid placement

courtyard

IPC-782-12-3-3

IPC-SM-782

Subject

LCC

Date

8/93

Section

12.3

Revision

Page3of4