CN201167435Y - A device for processing backplane signals - Google Patents

Abstract

The utility model discloses a backplane signal processing device, which comprises a signal sending layer, a signal destination layer and a backplane bottom layer; the device also includes a through hole and a blind hole as a signal path, and the through hole is connected with the blind hole; The through hole connects the signal sending layer and the bottom layer of the backplane; the blind hole connects the bottom layer of the backplane and the signal destination layer. In the utility model, the through hole is not directly drilled, but a blind hole directly passing through the bottom layer of the PCB board and the signal destination layer is separately established, so that no redundant signal path will be formed, and at the same time, the blind hole directly reaches the signal destination layer, and the size requirements It is lower than the back drilling method, and can guarantee the communication quality.

Description

A device for processing backplane signals

technical field

The utility model relates to a signal processing technology on a backplane, in particular to a backplane signal processing device.

Background technique

With the increasing bandwidth of data communication, high-speed design is widely used. In high-speed design above 5Gbps, the attenuation of the signal by the printed circuit board (PCB, Printed Circuit Board) and the reflection caused by the mismatch of line impedance, It is the biggest killer of high-speed signal integrity. Usually, when the high-speed signal path (trace) encounters a through hole on the PCB, due to the influence of the thickness of the PCB, the redundant path of the through hole will produce reflections. This redundant path is like a stub (stubs), especially for the backplane Pin through-holes for connector pins, stump reflections have a greater impact. As shown in Figure 1, the pin through hole itself in Figure 1 is metal, and a metal pad is provided at both ends of the pin through hole and the signal destination layer, and a wire is connected to the pad of the signal destination layer (not shown in the figure). ), the solid line indicates the normal signal path. The normal transmission of the signal is to flow from the sending layer through the pin through hole, the destination layer pad, and from the destination layer wire to the destination layer, but a part of the signal follows the reflection path shown by the dotted line, from the extra path of the pin through hole to the back The bottom pad of the board is reflected from the bottom layer to the destination layer, which will affect the communication quality. To eliminate this reflection, the stubs need to be removed. At present, the back-drilling method is used, as shown in Figure 2, to drill off the black part of the redundant path, so that the pin through hole becomes a blind hole that does not penetrate the backplane. Without redundant paths, the effect of reflected signals is eliminated.

In actual operation, due to the many signal layers and complex structure of the backplane, if backdrilling is used to eliminate the impact of tree stumps, different backdrilling sizes need to be formulated for different backplane thicknesses, signal layers, and vias. Not only the design is complicated, but also, when back-drilling pin through holes, on the one hand, it is difficult to accurately back-drill the size, and on the other hand, a little redundant path is usually left to ensure communication security. A small tree stump is formed between the blind holes, so there will still be a certain signal reflection, which will affect the communication quality.

Utility model content

In view of this, the main purpose of the present invention is to provide a backplane signal processing device, which not only has a simple design, but also can improve communication quality.

In order to achieve the above object, the technical solution of the utility model is achieved in that:

A processing device for a backplane signal, comprising a signal sending layer, a signal destination layer and a backplane bottom layer; the device also includes a through hole and a blind hole as a signal path, and the through hole is connected with the blind hole; the through hole is connected The signal sending layer and the bottom layer of the backplane; the blind hole connects the bottom layer of the backplane and the signal destination layer.

The through hole and the blind hole are connected by wiring at the bottom layer of the backplane.

The wiring length is determined according to the backplane wiring space.

There are pads at both ends of the through hole, and the pads are respectively located in the signal sending layer and the bottom layer of the backplane.

There are pads at both ends of the blind hole, and the pads are respectively located at the bottom layer of the backplane and the signal destination layer.

In the utility model, the through hole is not directly drilled, but a blind hole directly passing through the bottom layer of the PCB board and the signal destination layer is separately established, so that no redundant signal path will be formed, and at the same time, the blind hole directly reaches the signal destination layer, and the size requirements It is lower than the back drilling method, and can guarantee the communication quality.

Description of drawings

Figure 1 is a schematic diagram of the reflection of the pin through hole;

Fig. 2 is a schematic diagram of a small tree stump left after backdrilling through a pin hole in the prior art;

Fig. 3 is a schematic diagram of the blind hole structure of the utility model.

Detailed ways

The basic idea of the utility model is: all the signals are led to the bottom layer of the PCB board through the pin through holes, and then the signal of the bottom layer is led to the target layer through the blind hole by adopting the method of burying the blind hole, so that the signal takes a single path, thereby eliminating reflection.

The specific realization structure of the present utility model is illustrated below by taking Fig. 3 as an example.

The structure of the present utility model includes a pin through hole 1 and a blind hole 2, and the two ends of the pin through hole 1 are provided with pads 3, which connect the signal sending layer 4 and the bottom layer of the PCB board 5, and the two ends of the blind hole 2 are provided with pads. Connect the bottom layer 5 of the PCB board and the signal destination layer 6 , and on the bottom layer 5 of the PCB board, the pad of the pin through hole 1 is connected to the pad of the blind hole 2 through the wiring 7 .

The solid line with arrows in Figure 3 represents the signal path. The signal travels from the signal sending layer 4 through the pin hole 1 to the bottom layer 5 of the PCB board. The signal travels along the wiring 7 on the bottom layer 5 of the PCB board for a certain distance to reach the blind hole 2. The blind hole 2 reaches the signal destination layer 6, so as to ensure that the signal takes a single path from the signal sending layer 4 to the signal destination layer 6, and eliminates reflection.

In high-speed connectors for backplane applications, the above-mentioned blind hole design can be used to eliminate the influence of signal reflection. The height of the blind hole can be different according to the signal purpose layer, and the position of the blind hole is determined according to the space during wiring. In the utility model, the blind hole directly passes through the bottom layer of the PCB board and the signal destination layer, without forming redundant paths, and the size requirement is not as precise as that required by the back-drilling method, so as to better ensure the communication quality.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the protection scope of the present utility model.

Claims (5)

1, a kind of backboard Signal Processing device comprises that signal sends layer, signal target zone and backboard bottom; It is characterized in that this device comprises that also as the through hole of signal path and blind hole, described through hole is connected with blind hole; Described through hole connects signal and sends layer and backboard bottom; Described blind hole connects backboard bottom and signal target zone.

2, backboard Signal Processing device according to claim 1 is characterized in that, described through hole is connected by wiring at the backboard bottom with blind hole.

3, backboard Signal Processing device according to claim 2 is characterized in that, described length of arrangement wire is determined according to the backboard wiring space.

4, backboard Signal Processing device according to claim 1 is characterized in that, described through hole two ends have pad, and described pad lays respectively at signal and sends layer, backboard bottom.

5, backboard Signal Processing device according to claim 1 is characterized in that, described blind hole two ends have pad, and described pad lays respectively at backboard bottom, signal target zone.

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