WO2013007083A1

WO2013007083A1 - Two-layer printed circuit board, printing method thereof, and mobile communication terminal

Info

Publication number: WO2013007083A1
Application number: PCT/CN2011/083665
Authority: WO
Inventors: 刘玉鹏
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-07-08
Filing date: 2011-12-08
Publication date: 2013-01-17
Also published as: KR20140010991A; CN102300398A

Abstract

A two-layer printed circuit board, a printing method thereof, and a mobile communication terminal overcome the disadvantage of the high cost of a six-layer printed circuit board or a four-layer printed circuit board used by the existing low-end mobile communication terminal. The two-layer printed circuit board is based on the MT6251 platform. The diameter of a bonding pad is 0.27 millimeters. The line width of a wiring between two bonding pads is 0.075 millimeters. A minimum interval between the wiring and the bonding pad is 0.075 millimeters. A wire from a bonding pad in an inner row is threaded through a place between bonding pads in an outer row. The back of a main ground bonding pad of a main chip is a whole ground plane. A ground hole is opened after a C7 pin and a C8 pin are led outward. When the two-layer printed circuit board of the embodiment of the present invention is applied to the mobile communication terminal, compared with a mobile communication terminal using a four-layer printed circuit board or a six-layer printed circuit board, the cost is obviously reduced in the premise of no loss of functions and the competitive advantage of the product is improved.

Description

Two-layer printed circuit board and printing method thereof, mobile communication terminal

Technical field

The present invention relates to mobile communication technologies, and more particularly to a mobile communication terminal and a two-layer printed circuit board therefor, and a method of printing the two-layer printed circuit board.

Background technique

The printed circuit is a conductive pattern for connection between components formed on the surface of the insulating substrate or by a printing method in accordance with a pre-designed circuit. Printed circuit boards play an important role in electronics.

One of the main applications of printed circuit boards is low-end mobile communication terminals. The competition of low-end mobile communication terminals is mainly concentrated on the stability of performance and low price. At present, the printed circuit boards used in low-end mobile communication terminals are mainly six-layer printed circuit boards (referred to as six-layer boards) and four-layer printed circuit boards (referred to as four-layer boards).

Summary of the invention

In general, the cost of a two-layer printed circuit board is only half that of a four-layer printed circuit board, and only one-third of a six-layer printed circuit board. Therefore, applying two-layer printed circuit boards to low-end mobile communication. On the terminal, the cost of the mobile communication terminal will be significantly reduced.

The technical problem to be solved by the present invention is to provide a two-layer printed circuit board that can be applied to a mobile communication terminal, which overcomes the existing low-end mobile communication terminal and uses a six-layer printed circuit board or a four-layer printed circuit board. The disadvantage of higher board cost.

In order to solve the above technical problems, the present invention provides a two-layer printed circuit board based on the MT6251 platform, in the two-layer printed circuit board:

The pad diameter is 0.27 mm, the line width between the two pads is 0.075 mm, the minimum spacing between the traces and the pads is 0.075 mm, and the pads in the inner row are threaded from the outer pads. Out, the main ground pad of the main chip is a complete ground plane, and the C7 pin and C8 pin are led out to the ground. Preferably, a first capacitor is disposed on the VBAT (power supply) line on the two-layer printed circuit board.

Preferably, a second capacitor is disposed on the VBAT line on the two-layer printed circuit board.

Preferably, the second capacitor is a tantalum capacitor.

Preferably, the clock line and the data line of the memory on the two-layer printed circuit board are taken out from the baseband chip, and the clock line of the memory and the back side of the data line are a complete ground plane.

The present invention also provides a two-layer printed circuit board printing method for printing a two-layer printed circuit board based on the MT6251 platform, the method comprising:

Set the pad diameter on the two-layer printed circuit board to 0.27 mm, the line width between the two pads to 0.075 mm, and the minimum distance between the trace and the pad to 0.075 mm. The pads of the inner row are threaded out from the outer row pads, and the back surface of the main pad of the main chip is set to a complete ground plane, and the C7 pin and the C8 pin are led out to the outside ground hole.

Preferably, a first capacitance is provided on the VBAT line on the two-layer printed circuit board.

Preferably, a second capacitor is provided on the VBAT line on the two-layer printed circuit board.

Preferably, the clock line and the data line of the memory are disposed at a position leading from the baseband chip on the two-layer printed circuit board, and the clock line of the memory and the back side of the data line are set to a complete ground plane.

The present invention also provides a mobile communication terminal comprising any of the above two layers of printed circuit boards. Compared with the prior art, the two-layer printed circuit board of the embodiment of the present invention can ensure the function of the mobile communication terminal is normal when applied to the mobile communication terminal, compared with the existing four-layer printed circuit board or six-layer printing. The mobile communication terminal of the circuit board significantly reduces the cost without increasing the function, and improves the competitive advantage of the product.

Other features and advantages of the invention will be set forth in the description which follows, The objectives and other advantages of the invention may be realized and obtained by the structure particularly pointed in the appended claims. BRIEF abstract

The drawings serve to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. The technical solutions of the present invention are used to explain the technical solutions of the present invention, and do not constitute a limitation of the technical solutions of the present invention. In the drawing:

1 is a schematic diagram of a main chip outlet in an embodiment of the present invention.

2 is a schematic diagram of a first capacitor and a second capacitor on a VBAT line in an embodiment of the present invention. 3 is a schematic view of a pad of a main chip in an embodiment of the present invention.

4 is a schematic view showing the setting of a high speed signal line in the embodiment of the present invention.

FIG. 5 is a schematic flow chart of printing a two-layer printed circuit board according to an embodiment of the present invention. Preferred embodiment of the invention

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, by which the present invention can be applied to the technical solutions to the technical problems, and the implementation of the technical effects can be fully understood and implemented.

The embodiment of the present invention is based on the MT6251 platform, and the implemented two-layer printed circuit board reduces the diameter of the ball grid array (BGA) peripheral pad compared to the prior art, and reduces the line and the pad. The spacing between them. This is convenient for the inside of the pad to exit the surface.

Since only two mechanical layers can be punched on the two-layer printed circuit board, and the hole diameter of the mechanical hole is relatively large, it cannot be directly punched on the BGA pad. All the pads need to be pulled from the surface to the outside, and then played outside. Hole change layer. In this way, it is inevitable to thread between the pads.

The existing BGA pads have a diameter of 0.3 mm mm and the center distance between the two pads is 0.5 mm. According to the current industry regulations, the width of the trace is 0.1mm, and the safety distance between the trace and the pad is 0.1 mm. This way there is no way to thread between the two pads.

The embodiment of the present invention is as shown in FIG. 1. The center distance between the pad and the pad is 0.5 mm as in the prior art, and the pad diameter is set to 0.27 mm, and the line between the two pads of the BGA is traced. The width is set to 0.075mm, the rest is not the line from the BGA pad, the line width is set to 0.1mm; and the minimum spacing rule between the trace and the pad is set to 0.075mm. By changing the pad diameter and the width of the trace between the pads, the spacing between the trace and the pad is (0.5mm-0.27mm-0.075mm) /2=0.0775mm, which can satisfy the trace between the trace and the pad. The minimum pitch is 0.075mm, which allows the pads of the inner row to be routed from between the outer pads. Verified, adjust pad diameter and go The spacing between the lines and the pads can meet the functional requirements and mass production requirements of the mobile communication terminal.

In the main chip shown in FIG. 1, the positions indicated by the two ellipses are more commonly used. The above-mentioned pad diameter is set to 0.27 mm and the line width between the two pads of the BGA is set to 0.075 mm. Process. Of course, the main chip shown in Figure 1, the rest of the place also has the application of this process.

In the two-layer printed circuit board of the embodiment of the present invention, the VB AT line is on the surface layer, and a first capacitor having a capacity of 22 microfarads (uF) or more is provided on the VBAT line, and the first capacitor is, for example, a tantalum capacitor or a ceramic capacitor. The first capacitor can effectively eliminate the interference on the power supply, prevent the voltage drop of the VBAT from significantly affecting the RF phase, and greatly improve the stability of the RF index and the system. In this embodiment, the first capacitor on the VBAT line is as close as possible to the battery connector.

In addition, in a two-layer printed circuit board, PCB A (Printed Cirruit Board + Assembly,

After the PCB empty board passes the surface assembly technology and then passes through the entire process of the DIP plug-in, after the power is turned on, there is a possibility that the board emits sound. The embodiment of the present invention further sets a second capacitor having a capacity of 22 uF or more on the VBAT line, which can effectively eliminate the sound that may be emitted from the PCBA line; wherein the second capacitor is a tantalum capacitor. 2 is a schematic structural view of a first capacitor and a second capacitor according to an embodiment of the present invention, wherein the second capacitor is disposed as close as possible to the baseband processing chip. In the embodiment shown in FIG. 2, the ellipse on the left side indicates the position of the first capacitor, and the ellipse on the right side indicates the position of the second capacitor, wherein the first capacitor and the second capacitor are tantalum capacitors. In an embodiment of the invention, the main pad back of the master chip is a complete ground plane. In addition, some of the easily disturbed ground pads are led out to the outside, such as pulling the C7 and C8 pins to the outside. In this way, Time Division Distortion (TDD) NOISE is generated on the audio (a noise generated by the radio frequency module periodically transmitting and receiving information generated by the time division duplex communication mode). The copper area in the ellipse in Figure 3 is the ground plane, and the ground pin in the ellipse is the main grounding pin of the chip.

The memory (MEMEORY) has a high clock frequency that can reach tens or hundreds of megahertz (MHz). If the clock and data lines of the memory are exposed outside, or are placed back to back with other sensitive traces, there may be some risk to the stability of the system. In the embodiment of the present invention, as shown in Fig. 4, the clock line and the data line of the memory (MEMORY) (the high-brightness line shown in the ellipse in Fig. 4) are taken out from the baseband chip, and the back side thereof is a complete ground plane.

FIG. 5 is a schematic flow chart of printing a two-layer printed circuit board according to an embodiment of the present invention. As shown in Figure 5, In the process of printing a two-layer printed circuit board based on the MT6251 platform, the embodiment of the present invention mainly includes the following steps:

Set the center distance between the pad and the pad on the two-layer printed circuit board to be 0.5 mm as in the prior art, set the pad diameter to 0.27 mm, and route the two pads. The line width is set to 0.075 mm, and the minimum spacing between the trace and the pad is set to 0.075 mm. Thus, the space between the trace and the pad is (0.5mm-0.27mm-0.075mm) /2=0.0775mm, and the pads of the inner row are routed from the outer pads.

Set the first capacitor (such as tantalum capacitor or ceramic capacitor) on the VBAT line on the two-layer printed circuit board as close as possible to the battery connector. Its capacity is 22uF or more, which can effectively eliminate the interference on the power supply. The RF indicators and the stability of the system have been greatly improved.

The second capacitor (tantalum capacitor) is placed on the VBAT line on the two-layer printed circuit board as close as possible to the baseband processing chip. Its capacity is 22uF or more, which can effectively eliminate the sound of the PCBA line.

The main ground pad back of the main chip on the two-layer printed circuit board is set to a complete ground plane, and some easily disturbed ground pads are led out to punch holes, for example, the C7 pin and the C8 pin are taken out to the outside. Playing the hole, effectively avoiding TDD NOISE on the audio.

The clock line and the data line of the memory (MEMORY) on the two-layer printed circuit board are taken out from the baseband chip, and the back side of the clock line and the data line are set to a complete ground plane, which reduces the clock line and data line exposure of the memory. The risk of system stability on the outside, or with other sensitive traces placed back to back.

Embodiments of the present invention also include applying the aforementioned two-layer printed circuit board to a mobile communication terminal. For details, refer to the description of the two-layer printed circuit board in the foregoing embodiment, which is not mentioned here.

The embodiment of the present invention realizes the threading of the inner row of pads from the outer row pads by reducing the pad diameter and the line width of the inner portion of the BGA, thereby ensuring the functional requirements and mass production requirements of the mobile communication terminal. . The embodiment of the invention effectively eliminates the interference on the power supply by setting the first tantalum capacitor on the VBAT line, and greatly improves the stability of the radio frequency index and the system. Embodiments of the present invention effectively eliminate the possible sound of the PCBA line by providing a second tantalum capacitor on the VBAT line. Embodiments of the present invention set the back surface of the ground pad of the main chip to be relatively complete The ground plane avoids the generation of TDD NOISE on the audio. The embodiment of the present invention improves the stability of the system by setting a complete ground plane on the back of the MEMORY clock and data lines.

While the embodiments of the present invention have been described above, the described embodiments are merely for the purpose of understanding the invention and are not intended to limit the invention. Any modification and variation of the form and details of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention. It is still subject to the scope defined by the appended claims.

INDUSTRIAL APPLICABILITY When applied to a mobile communication terminal, the two-layer printed circuit board of the embodiment of the present invention can ensure that the function of the mobile communication terminal is normal, compared with the existing four-layer printed circuit board or six-layer printed circuit board. The mobile communication terminal significantly reduces the cost and improves the competitive advantage of the product without losing the function.

Claims

Claim

1. A two-layer printed circuit board based on the MT6251 platform. In the two-layer printed circuit board: the pad diameter is 0.27 mm, and the line width between the two pads is 0.075 mm. The minimum spacing between the pads is 0.075 mm. The pads in the inner row are routed from the outer pad. The main pad on the main chip has a complete ground plane. The C7 and C8 pins are Lead out to the outside and hit the hole.

2. A two-layer printed circuit board according to claim 1, wherein:

A first capacitor is disposed on the power supply VBAT line of the two-layer printed circuit board.

3. The two-layer printed circuit board of claim 1 wherein:

A second capacitor is disposed on the VBAT line on the two-layer printed circuit board.

4. The two-layer printed circuit board of claim 3, wherein:

The second capacitor is a tantalum capacitor.

5. The two-layer printed circuit board of claim 1 wherein:

The clock lines and data lines of the memory on the two-layer printed circuit board are taken out from the baseband chip, and the clock lines of the memory and the back side of the data lines are complete ground planes.

6. A two-layer printed circuit board printing method for printing a two-layer printed circuit board based on the MT6251 platform, the method comprising:

7. The printing method according to claim 6, wherein:

8. The printing method according to claim 6, wherein: A second capacitor is disposed on the VBAT line on the two-layer printed circuit board.

9. The printing method according to claim 6, wherein:

The clock lines and data lines of the memory are placed at a position from the baseband chip on the two-layer printed circuit board, and the clock lines of the memory and the back side of the data lines are set to a complete ground plane.

A mobile communication terminal comprising the two-layer printed circuit board according to any one of claims 1 to 5.