CN114449752A

CN114449752A - Common pad of SMT

Info

Publication number: CN114449752A
Application number: CN202111682101.8A
Authority: CN
Inventors: 刘丹; 肖安勇; 王安顺
Original assignee: Sichuan Tianyi Comheart Telecom Co Ltd
Current assignee: Sichuan Tianyi Comheart Telecom Co Ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-05-06

Abstract

The invention discloses an SMT (surface mount technology) common bonding pad, which comprises two symmetrically arranged bonding pads, wherein each bonding pad comprises a large-size packaging part and a small-size packaging part, the small-size packaging parts of the two bonding pads are arranged on the inner side, the large-size packaging part is arranged on the outer side, the combination of the two small-size packaging parts is used for packaging small-size devices, and the two large-size packaging parts are used for packaging large-size devices; still include positioning element, positioning element including set up in holding tank, toughness butt joint piece on the pad lateral wall, toughness butt joint piece the bottom with the interior wall connection of holding tank, the top slope upwards stretches out the holding tank is used for the installation on the PCB the lateral wall of the constant head tank of pad is provided with the spacing groove, works as the pad set up in when among the constant head tank, toughness butt joint piece set up partially in among the spacing groove.

Description

Common pad of SMT

Technical Field

The invention relates to the field of pad structure design, in particular to an SMT (surface mount technology) common pad.

Background

PCBA is through PCB vacant board SMT upper part, through the whole process of DIP plug-in components, wherein, SMT (surface Mounted technology) surface mounting technique mainly utilizes the mounter to paste some microminiature parts onto PCB board, and its production flow is: positioning a PCB, printing solder paste, mounting by a mounter, passing through a reflow furnace and performing manufacturing inspection; DIP is a "plug-in", that is, a part is inserted on a PCB board, which is an integrated part in the form of a plug-in when the size of some parts is large and it is not suitable for mounting technology. The main production flow is as follows: sticking gum, inserting, checking, wave soldering, printing and manufacturing and checking. With the increasing popularity of electronic products, the replacement frequency of the products is faster and faster, and the utilization rate of the PCBA in the core components of the electronic products is also increased. Under the condition of general shortage of electronic materials at present, the purchasing cost of electronic devices is higher and higher, and even devices suitable for packaging cannot be purchased frequently, so that the manufacturing cost and the delivery cycle of products are influenced. For example, the 0201 type chip resistor and the 0402 type chip resistor are commonly used on a display module, the packaging sizes of the 0201 type chip resistor and the 0402 type chip resistor are different, the 0402 type chip resistor is larger than the packaging size of the 0201 type chip resistor, common pads are designed for one chip resistor, the commonality is poor, when substitute delivery occurs, redesign and manufacturing are needed, and the production period and the production cost are increased.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the object of the present invention is to: an SMT common bonding pad is provided, which has good compatibility and can be compatible with the welding packages of devices with different sizes.

In order to achieve the purpose, the invention provides the following technical scheme:

a common welding disc for SMT comprises two symmetrical welding discs, wherein each welding disc comprises a large-size packaging part and a small-size packaging part, the small-size packaging parts of the two welding discs are arranged on the inner side, the large-size packaging part is arranged on the outer side, the combination of the two small-size packaging parts is used for packaging small-size devices, and the two large-size packaging parts are used for packaging large-size devices;

still include positioning element, positioning element including set up in holding tank, toughness butt joint piece on the pad lateral wall, toughness butt joint piece the bottom with the interior wall connection of holding tank, the top slope upwards stretches out the holding tank is used for the installation on the PCB the lateral wall of the constant head tank of pad is provided with the spacing groove, works as the pad set up in when among the constant head tank, toughness butt joint piece set up partially in among the spacing groove.

As a further improvement of the above, the spacing between the two small-sized packages is 0.21 mm.

As a further improvement of the above aspect, a dimension in a direction from one pad to another pad is a length, a dimension from one side of the one pad to the other side thereof is a width, and a length of the small-sized package portion is 0.07 mm.

As a further improvement of the above, the length of the large-size package portion is 0.4 mm.

As a further improvement of the above, the total length of the two pads is 1.15 mm.

As a further improvement of the scheme, the contact surfaces of the bottom wall of the welding disc and the bottom wall of the positioning groove are respectively provided with limiting teeth which are arranged in a staggered mode.

As a further improvement of the scheme, a plurality of small bulges are arranged on the bonding pad.

As a further improvement of the scheme, an elastic cushion layer is arranged between the flexible abutting sheet and the bonding pad.

Compared with the prior art, the invention has the following beneficial effects:

1. the device can be compatible with the chip resistors with different sizes, so that the compatibility and the adaptability of the device are improved, and the production cost is reduced.

2. The board surface space of the PCB board can not be increased, and the compatible purpose can be realized without replacing the PCB board.

3. The top wall of spacing groove with the top butt of toughness butt piece makes the pad is difficult for following drop on the PCB board. The reliability of the device is improved.

Drawings

FIG. 1 is a diagram of a common SMT pad configuration according to the present invention;

FIG. 2 is a schematic diagram of a pad and PCB connection;

FIG. 3 is an enlarged view of FIG. 2 at A;

fig. 4 is an enlarged view of fig. 2 at B.

List of reference numerals

1-a large-size packaging part, 2-a small-size packaging part, 3-a bonding pad, 4-a PCB, 5-a small bump, 6-an accommodating groove, 7-a limiting groove and 8-a toughness butting sheet.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or apparatus must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The invention will be further described with reference to the accompanying drawings, but the scope of the invention is not limited to the following.

As shown in fig. 1 and 2, to solve the problems in the prior art, the SMT common pad provided by the present invention includes two symmetrically arranged pads, where the pad includes a large-sized packaging portion and a small-sized packaging portion, the small-sized packaging portion of the two pads is arranged at the inner side, the large-sized packaging portion is arranged at the outer side, the combination of the two small-sized packaging portions is used for packaging small-sized devices, and the two large-sized packaging portions are used for packaging large-sized devices; compared with the prior art, by taking the simultaneous compatibility of the 0201 type chip resistor and the 0402 type chip resistor as an example, when the bonding pad is used, the 0201 type chip resistor with the small size is welded through the two small-size packaging parts, and the 0402 type chip resistor with the large size is welded through the two large-size packaging parts, under the structure, the compatibility of chip resistors with different sizes can be ensured while the board surface space of a PCB (printed circuit board) is not increased and the PCB is not replaced, the compatibility and the adaptability of the device are improved, the production cost is reduced, and in addition, when some devices in the market are in shortage, due to the compatibility of the device, a producer can flexibly select devices with lower cost, and the production cost is further reduced.

As shown in fig. 3 and 4, in the process of soldering a device, it is known that a pad is likely to fall off due to an excessively long soldering time or repeated soldering, and in order to solve the above problems in the prior art, the device further includes a positioning component, where the positioning component includes a receiving groove and a flexible contact piece, the receiving groove and the flexible contact piece are disposed on the side wall of the pad, the bottom end of the flexible contact piece is connected to the inner wall of the receiving groove, the top end of the flexible contact piece extends obliquely upward from the receiving groove, a position-limiting groove is disposed on the side wall of a position-limiting groove on the PCB board, and when the pad is disposed in the position-limiting groove, the flexible contact piece is partially disposed in the position-limiting groove. Particularly, when the installation during the pad, press into the pad during the in-process among the constant head tank on the PCB board, toughness butt piece is at first crowded into among the holding tank, avoid it to cause the hindrance to the removal of pad, work as toughness butt piece removes when limiting groove department, under the effect of its elastic restoring force, toughness butt piece's top is followed pop out among the holding tank and is got into among the limiting groove, the roof of limiting groove with toughness butt piece's top butt makes the pad is difficult for following drop on the PCB board. In this device, toughness butt piece can adopt the brass material to make, and is further, toughness butt piece with be provided with the elastic cushion layer between the pad. The elastic cushion layer can play an elastic supplementary role for the toughness butt joint piece, so that the toughness butt joint piece cannot enter the limiting groove, and the elastic cushion layer can be made of high-temperature-resistant rubber.

As a further improvement of the scheme, the bottom wall of the pad and the contact surface of the bottom wall of the positioning groove are respectively provided with limiting teeth which are arranged in a staggered mode, the limiting teeth on the pad and the positioning groove are increased firstly, the contact area of the pad and the PCB is increased secondly, a transverse limiting effect is achieved secondly, and the connection strength between the pad and the PCB is further improved.

As is known, the 0201 chip resistor standard document suggests that the inner pitch is 0.23mm, but because PCB manufacturers have errors in forming the bonding pads, the device is further improved in that the pitch between two small-sized packaging parts is 0.21mm, thereby preventing the problems of tombstoning and offset due to the influence of solder paste tension when the pitch between two bonding pads is too large.

As a further improvement of the above scheme, the dimension along the direction from one pad to the other pad is a length, the dimension along one side of the pad to the other side of the pad is a width, the length of the small-sized packaging part is 0.07mm, and the problem of migration caused by the influence of solder paste tension when the 0201 chip resistor is directly pasted on the pad is reduced.

As a further improvement of the scheme, the length of the large-size packaging part is 0.4mm, the total length of the two bonding pads is 1.15mm, and the welding requirement of the 0402 type chip resistor is ensured.

It is known that, as the overall size of the electronic device is smaller and smaller, the integration level inside the electronic device is higher and higher, which leads to the continuous increase of the heat flux density of the electronic device.

While the preferred embodiments of the present invention have been illustrated in detail in the accompanying drawings, the invention is not limited to the details of the embodiments illustrated in the above description, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention. It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition. In addition, any combination of the various embodiments of the present invention can be made, and the same should be considered as the disclosure of the present invention as long as the idea of the present invention is not violated.

Claims

1. An SMT common pad, comprising: the packaging structure comprises two symmetrically arranged bonding pads, wherein each bonding pad comprises a large-size packaging part and a small-size packaging part, the small-size packaging parts of the two bonding pads are arranged on the inner side, the large-size packaging part is arranged on the outer side, the combination of the two small-size packaging parts is used for packaging small-size devices, and the two large-size packaging parts are used for packaging large-size devices;

2. An SMT common pad according to claim 1, wherein: the spacing between the two small size packages is 0.21 mm.

3. An SMT common pad according to claim 2, wherein: the dimension along one pad to another pad direction is length, the dimension along one side of one pad to its opposite side is width, the length of small-size encapsulation portion is 0.07 mm.

4. An SMT common pad according to claim 3, wherein: the length of the large-size packaging part is 0.4 mm.

5. An SMT common pad according to claim 4, wherein: the total length of the two pads is 1.15 mm.

6. An SMT common pad according to claim 1, wherein: and limiting teeth are respectively arranged on the contact surfaces of the bottom wall of the bonding pad and the bottom wall of the positioning groove and are arranged in a staggered mode.

7. An SMT common pad according to claim 1, wherein: and a plurality of small bulges are arranged on the bonding pad.

8. An SMT common pad according to claim 1, wherein: an elastic cushion layer is arranged between the toughness abutting sheet and the welding disc.