IPC-SM-782A-表面贴装焊盘图形设计标准.pdf.pdf - 第151页

1.0 SCOPE This subsection provides the component and land pattern dimensions for square SQFP (Shrink Quad Flat Pack) and QFP (metric plastic quad flat pack) components. Basic construc- tion of the SQFP device is also cov…

6.0 TOLERANCE AND SOLDER JOINT ANALYSIS

Figure 4 provides an analysis of tolerance assumptions and

resultant solder joints based on the land pattern dimensions

shown in Figure 3. Tolerances for the component dimensions,

the land pattern dimensions (fabrication tolerances on the

interconnecting substrate), and the component placement

equipment accuracy are all taken into consideration.

Figure 4 provides the solder joint minimums for toe, heel, and

side fillets, as discussed in Section 3.3. The tolerances are

addressed in a statistical mode, and assume even distribution

of the tolerances for component, fabrication, and placement

accuracy.

Individual tolerances for fabrication (‘‘F’’) and component

placement equipment accuracy (‘‘P’’) are assumed to be as

given in the table. These numbers may be modified based on

user equipment capability or fabrication criteria. Component

tolerance ranges (C

, and C

) are derived by subtracting

minimum from maximum dimensions given in Figure 2. The

user may also modify these numbers, based on experience

with their suppliers. Modification of tolerances may result in

alternate land patterns (patterns with dimensions other than

the IPC registered land pattern dimensions).

The dimensions for minimum solder fillets at the toe, heel, or

side (J

) have been determined based on industry

empirical knowledge and reliability testing. Solder joint

strength is greatly determined by solder volume. An observ-

able solder fillet is necessary for evidence of proper wetting.

Thus, the values in the table usually provide for a positive sol-

der fillet. Nevertheless, the user may increase or decrease the

minimum value based on process capability.

RLP No.

Tolerance

Asssumptions

(mm)

Solder Joint

Toe (mm) Heel (mm) Side (mm)

FPC

min J

max C

min J

max C

min J

max

530A 0.10 0.10 0.50 0.27 0.53 0.61 0.27 0.58 0.10 -0.01 0.08

531A 0.10 0.10 0.50 0.29 0.55 0.61 0.24 0.56 0.10 -0.01 0.08

532A 0.10 0.10 0.50 0.24 0.50 0.61 0.29 0.61 0.10 -0.01 0.08

533A 0.10 0.10 0.50 0.32 0.58 0.61 0.22 0.53 0.10 -0.01 0.08

534A 0.10 0.10 0.50 0.27 0.53 0.61 0.27 0.58 0.10 -0.01 0.08

535A 0.10 0.10 0.50 0.32 0.57 0.61 0.22 0.53 0.10 -0.01 0.08

Figure 4 Tolerance and solder joint analysis

Zmax

Lmin

▼

/2 T

min

Zmax = Lmin + 2J

min + T

Where:

min = Minimum toe fillet

= Combined tolerances

at toe fillet

Smax

min

Gmin = Smax - 2J

min - T

Where:

min = Minimum heel fillet

= Combined tolerances

at heel fillet

/2 T

Xmax

Xmax = Wmin + 2J

min + T

Where:

min = Minimum side fillet

= Combined tolerances

at side fillet

▼

Toe Fillet

▼

Heel Fillet Side Fillet

▼

max

min

▼

Gmin

▼

/2 T

max

▼

Wmin

▼

IPC-782-11-1-4

IPC-SM-782

Subject

PQFP

Date

5/96

Section

11.1

Revision

Page4of4

1.0 SCOPE

This subsection provides the component and land pattern

dimensions for square SQFP (Shrink Quad Flat Pack) and QFP

(metric plastic quad flat pack) components. Basic construc-

tion of the SQFP 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 pattern dimensions.

2.0 APPLICABLE DOCUMENTS

See Section 11.0 and the following for documents applicable

to this subsection.

2.1 Electronic Industries Association (EIA)

JEDEC Publication 95

Registered and Standard Outlines for

Solid State and Related Products, ‘‘Metric Quad Flat Pack

Family 3.2 mm Footprint,’’ Outline MO-108, issue ‘‘A,’’ dated

10/90

Application for copies should be addressed to:

Global Engineering Documents

1990 M Street N.W.

Washington, DC

2.2 Electronic Industries Association of Japan (EIAJ)

EIAJ-ED-7404-1

General Rules for the Preparation of Outline

Drawings of Integrated Circuits Fine Pitch Quad Flat Packages

(dated January 26, 1989)

3.0 COMPONENT DESCRIPTIONS

Flatpacks are widely used in a variety of applications for com-

mercial, industrial, or military electronics.

3.1 Basic Construction See Figure 1.

The shrink quad flat pack has been developed for applications

requiring low height and high density. The SQFP, along with

the TSOP components, are frequently used in memory card

applications. The square SQFP family comes in 13 standard

sizes, each of which sizes can come in either a 0.5, 0.4, or 0.3

mm pitch. There are therefore 39 configurations for square

SQFPs.

Two different pin counts are allowed for each package and

the component will still meet the standard (e.g., a 5x5 pack-

age with a 0.3 mm pitch can have either 56 or 48 pins, and

still meet EIAJ-7404-1).

QFPs are also square and come in larger pitches. Wherever

applicable, the body sizes of the components identified in Fig-

ures 2 and 3 show the relationships and pin numbers for

SQFPs and QFPs that have the same body size.

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 number

and an index area. The index area shall identify the location of

pin 1.

3.1.3 Carrier Package Format The carrier package for-

mat for flatpacks may be tube format; but, in most instances,

flatpacks are delivered in a carrier tray.

3.1.4 Process Considerations SQFPs and QFPs are usu-

ally processed using standard solder reflow processes. Parts

should be capable of withstanding ten cycles through a stan-

dard reflow system operating at 215°C. Each cycle shall con-

sist of 60 seconds exposure and 215°C.

IPC-782-11-2-1

Figure 1 SQFP & QFP (Square)

IPC-SM-782

Surface Mount Design

and Land Pattern Standard

Date

5/96

Section

11.2

Revision

Subject

SQFP/QFP (Square)

Page1of10

4.0 COMPONENT DIMENSIONS

In this subsection, Figures 2a–2d provide the component

dimensions for SQFP (Square) components. (Also see

pages 4, 6 and 8.)

Component

Identiﬁer

L (mm) S (mm) W (mm) T (mm)

(mm)

min max min max min max min max ref ref basic max

SQFP 5X5-24 6.80 7.20 5.20 5.89 0.10 0.30 0.40 0.80 5.00 5.00 0.50 1.70

SQFP 5X5-32 6.80 7.20 5.20 5.89 0.10 0.30 0.40 0.80 5.00 5.00 0.50 1.70

SQFP 5X5-32-F 6.80 7.20 5.20 5.89 0.05 0.22 0.40 0.80 5.00 5.00 0.40 1.70

SQFP 5X5-40 6.80 7.20 5.20 5.89 0.05 0.22 0.40 0.80 5.00 5.00 0.40 1.70

SQFP 5X5-48 6.80 7.20 5.20 5.89 0.05 0.15 0.40 0.80 5.00 5.00 0.30 1.70

SQFP 5X5-56 6.80 7.20 5.20 5.89 0.05 0.15 0.40 0.80 5.00 5.00 0.30 1.70

SQFP 6X6-32 7.80 8.20 6.20 6.89 0.10 0.30 0.40 0.80 6.00 6.00 0.50 1.70

SQFP 6X6-40 7.80 8.20 6.20 6.89 0.10 0.30 0.40 0.80 6.00 6.00 0.50 1.70

SQFP 6X6-40-F 7.80 8.20 6.20 6.89 0.05 0.22 0.40 0.80 6.00 6.00 0.40 1.70

SQFP 6X6-48 7.80 8.20 6.20 6.89 0.05 0.22 0.40 0.80 6.00 6.00 0.40 1.70

SQFP 6X6-56 7.80 8.20 6.20 6.89 0.05 0.15 0.40 0.80 6.00 6.00 0.30 1.70

SQFP 6X6-64 7.80 8.20 6.20 6.89 0.05 0.15 0.40 0.80 6.00 6.00 0.30 1.70

SQFP 7X7-40 8.80 9.20 7.20 7.89 0.10 0.30 0.40 0.80 7.00 7.00 0.50 1.70

SQFP 7X7-48 8.80 9.20 7.20 7.89 0.10 0.30 0.40 0.80 7.00 7.00 0.50 1.70

SQFP 7X7-56 8.80 9.20 7.20 7.89 0.05 0.22 0.40 0.80 7.00 7.00 0.40 1.70

SQFP 7X7-64 8.80 9.20 7.20 7.89 0.05 0.22 0.40 0.80 7.00 7.00 0.40 1.70

SQFP 7X7-72 8.80 9.20 7.20 7.89 0.05 0.15 0.40 0.80 7.00 7.00 0.30 1.70

SQFP 7X7-80 8.80 9.20 7.20 7.89 0.05 0.15 0.40 0.80 7.00 7.00 0.30 1.70

Figure 2a SQFP (Square) component dimensions

0~ 0.25

▼

0~ 10°

▼

IPC-782-11-2-2a

IPC-SM-782

Subject

SQFP/QFP (Square)

Date

5/96

Section

11.2

Revision

Page2of10