Surface-mounted device packaging heat dissipation bonding pad structure

Abstract

The utility model discloses a surface-mounted device packaging heat dissipation bonding pad structure, which comprises a plurality of layers of plates which are overlapped up and down, copper foils are attached to the positions, corresponding to heat dissipation bonding pads, on each layer of plate, a heat dissipation via hole is formed in the center of each heat dissipation bonding pad, the heat dissipation via holes sequentially penetrate through all the plates, and the plates are well connected through the heat dissipation via holes. And a window corresponding to the surface-mounted device is arranged on the plate at the bottommost layer to expose the copper foil at the inner side. According to the utility model, the windowing treatment is carried out on the bottommost plate, the copper foil of the inner layer is exposed, the heat of the surface-mounted device is transmitted to the bottommost plate through the heat dissipation via holes, and the heat dissipation area is enlarged through the windowing area, so that the overall heat dissipation efficiency is effectively accelerated.

Description

Technical Field

[0001] This utility model relates to the field of PCB heat dissipation technology, and in particular to a heat dissipation pad structure for surface mount device packaging. Background Technology

[0002] In existing technology, the D2PAK packaged 7805 chip operates with an input voltage Vin = +7.6V, an output Vout = +5V, an output current Iout = 0.56A, and a power consumption P = (Vin - Vout) * Iout = 1.456W. The measured temperature rise is 68.77℃, and the device temperature is 96℃. If the machine operates in a harsh ambient temperature of 45℃, the device temperature will reach as high as 113.77℃, which will severely impact the device's lifespan and the PCB board, thereby affecting the product's lifespan.

[0003] Therefore, existing technologies have shortcomings and need to be improved. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a surface-mount device packaging heat dissipation pad structure.

[0005] The technical solution of this utility model is as follows: A surface mount device (SMD) packaging heat dissipation pad structure is provided, including a PCB board. The PCB board is provided with heat dissipation pads corresponding to the SMD devices. The PCB board includes several layers of boards stacked on top of each other. Copper foil is attached to the position of the heat dissipation pad on each layer of board. A heat dissipation via is provided in the center of the heat dissipation pad. The heat dissipation via passes through all the boards in sequence. The boards are well connected to each other through the heat dissipation via. The bottom layer of board is provided with an opening corresponding to the SMD device to expose the inner copper foil.

[0006] Furthermore, a tin layer is sprayed onto the copper foil surface of the bottommost plate corresponding to the window area.

[0007] Furthermore, thermally conductive putty is applied to the copper foil surface of the bottommost plate corresponding to the window area.

[0008] Furthermore, the copper foil has a thickness of 1 oz.

[0009] By adopting the above solution, this utility model exposes the inner copper foil by opening windows on the bottom layer of the substrate, which allows the heat from the surface-mount device to be transferred to the bottom layer of the substrate through heat dissipation holes, and expands the heat dissipation area through the windowed area, thereby effectively accelerating the overall heat dissipation efficiency. Attached Figure Description

[0010] Figure 1 This is a cross-sectional schematic diagram of the present invention.

[0011] Figure 2This is a bottom view of the present invention. Detailed Implementation

[0012] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0013] Please see Figure 1 , Figure 2 This utility model provides a surface mount device (SMD) packaging heat dissipation pad structure, including a PCB board 1. The PCB board 1 has heat dissipation pads corresponding to the SMD devices. The PCB board 1 includes several layers of boards 11 stacked on top of each other. Each layer of board 11 has copper foil 2 attached to the position corresponding to the heat dissipation pad. A heat dissipation via 12 is provided in the center of the heat dissipation pad. The heat dissipation via 12 passes through all the boards 11 in sequence. The layers of boards 11 are well connected through the heat dissipation via 12. The bottom layer of board 11 has a window 13 corresponding to the SMD device to expose the inner copper foil 2.

[0014] In the embodiments provided by this utility model, the PCB board 1 consists of four layers 11 from top to bottom: top, layer 2, layer 3, and bottom. A plurality of heat dissipation pads are densely arranged in the areas of the PCB board 1 corresponding to the surface-mount devices, and heat dissipation vias 12 are used to connect the four layers 11 at the center of the heat dissipation pads. In the embodiments provided by this utility model, the surface-mount device is a 7805 chip in a D2PAK package.

[0015] The top, layer 2, layer 3, and bottom layers are well connected through heat dissipation vias 12, ensuring stable and reliable heat dissipation performance of the PCB board 1. By creating a window 13 on the bottom layer 11, the inner copper foil 2 is exposed, allowing the heat from the 7805 chip to be transferred to the bottom layer 11 through the heat dissipation vias 12. The heat dissipation area is expanded through the window 13, thereby effectively accelerating the overall heat dissipation efficiency.

[0016] A tin layer 3 is sprayed onto the surface of the copper foil 2 of the bottom layer of the board 11 corresponding to the window 13 area. Spraying tin onto the surface of the copper foil 2 removes the influence of the green oil 14 on the surface of the copper foil 2, reduces the overall thermal resistance, and can effectively improve the overall heat conduction and heat dissipation efficiency.

[0017] Thermally conductive putty 4 is applied to the surface of the copper foil 2 of the bottommost plate 11 corresponding to the window 13 area. During use, the PCB board 1 is placed on the mounting plate 5, and due to the window 13, the copper foil 2 and the mounting plate 5 are not in direct contact. Therefore, by applying thermally conductive putty 4 to the copper foil 2 in the window 13 area, the heat transferred from the copper foil 2 is effectively transferred to the mounting plate 5 through the thermally conductive putty 4, and the mounting plate 5 dissipates the heat into the outside air, achieving the purpose of heat dissipation.

[0018] The copper foil 2 is 1 oz thick, which avoids increasing the overall thickness while effectively transferring the heat generated by the 7805 chip during operation, thereby improving heat dissipation efficiency.

[0019] In the existing technology, with a chip input voltage Vin = +7.6V, output Vout = +5V, and output current Iout = 0.56A, the actual measured device temperature is 96℃, with a temperature rise of 68.77℃. If operated at an ambient temperature of 45℃ for 1 hour and 40 minutes, the device temperature will rise to 113.77℃, which will seriously affect the product's lifespan.

[0020] Using the heat dissipation pad structure provided by this invention, with the chip input voltage Vin = +7.6V, output Vout = +5V, and output current Iout = 0.56A, the actual measured device temperature was 83.32℃, with a temperature rise of 54.68℃. If operated under the same conditions at an ambient temperature of 45℃ for 1 hour and 40 minutes, the device temperature rises to 99.68℃. Compared to existing technologies, this effectively reduces the device temperature, calculated to be 14℃ lower, thus ensuring the overall lifespan of the product.

[0021] In summary, this utility model exposes the inner copper foil by creating a window on the bottom layer of the substrate, allowing the heat from the surface-mount device to be transferred to the bottom layer of the substrate through heat dissipation vias. The heat dissipation area is also expanded through the windowed area, thereby effectively accelerating the overall heat dissipation efficiency.

[0022] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A surface-mount device (SMD) package thermal pad structure, comprising a PCB board, wherein thermal pads are provided on the PCB board corresponding to the SMD device, characterized in that... The PCB board includes several layers of boards stacked on top of each other. Each layer of board has copper foil attached to the position of the heat dissipation pad. The center of the heat dissipation pad is provided with a heat dissipation via. The heat dissipation via passes through all the boards in sequence. The boards are well connected to each other through the heat dissipation via. The bottom layer of board has a window provided for the surface mount device to expose the inner copper foil.

2. The surface mount device packaging heat dissipation pad structure according to claim 1, characterized in that, A tin layer is sprayed onto the copper foil surface of the bottom layer of the board corresponding to the window area.

3. The surface mount device package heat dissipation pad structure according to claim 1, characterized in that, Thermally conductive putty is applied to the copper foil surface of the bottom layer of the board corresponding to the window area.

4. The surface mount device package heat dissipation pad structure according to claim 1, characterized in that, The copper foil has a thickness of 1 oz.

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