KR100279733B1 - PCB stacking and wiring structure - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a PCB stacking structure and a wiring structure for controlling odd mode impedance 50 [다층] in a thin multilayer board, and includes prepreg-laminate-prepreg or laminate- In a PCB laminate structure laminated in the order of Laminate-Prepreg-Laminate, a ratio of dielectric thickness 1: 2: 1 is formed, and one signal above and below the laminate has the same amplitude and voltage polarity or Prepreg-laminate-prepreg is formed by forming differential drive wirings of dual-offset stripline structures that are parallel to each other that are converted / driven and transmitted to two signals having opposite current flow directions. -Three-layer total dielectric thickness 0.4 in PCB laminates in the order of Laminate-Prepreg or Laminate-Prepreg-Laminate PCB laminate structure and wiring structure that can realize odd mode impedance of 50 [Ω] of differential driving with minimum conductor width of about 0.1 [mm] when thinning from 2 [mm] to 0.62 [mm] The ratio of dielectric thickness is 1 by using a PCB stack structure in the order of prepreg-laminate-prepreg or laminate-prepreg-laminate. When the ratio is 2: 1, the maximum impedance of the odd mode of the differential driving can be obtained, and in this structure, the odd mode impedance of the dual-offset stripline is weaker than that of the conventional structure. It can increase 8 ~ 16%.

Description

PC laminate structure and wiring structure

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a PCB laminate structure and a wiring structure, in particular, a three-layer total dielectric thickness of 0.42 in a PCB laminate structure of prepreg-laminate-prepreg or laminate-prepreg laminate. PCB laminate structure and wiring structure to realize odd mode impedance of 50 [50] of differential driving with minimum conductor width of about 0.1 [mm] when it is thinned [mm] ~ 0.62 [mm] will be.

1 is a laminated structure of a conventional differential drive wiring, which is most commonly used at present. Dielectric thickness of Prepreg 1 (1): Dielectric thickness of Laminate 1 (2): Prepreg 2 (3), the thickness ratio of the dielectric material is 1: 1: 1, the wiring T + represents the differential drive wiring plus (+), and the wiring T- represents the differential drive wiring minus (-).

2 is a laminated structure of a conventional differential drive wiring, which is sometimes used now, and has a dielectric thickness of laminate 2 4: dielectric thickness of prepreg 5 laminate 3 3. ) Dielectric thickness ratio is 1: 1: 1.

3 is an exemplary diagram for calculating odd mode impedance of a differential driving wiring.

In this structure, the odd mode impedance of the differential drive wiring Z _oo The impedance of the good mode is Z _oe Then, each value is given by the following equations (1) to (5).

only, ε _r Is the relative permittivity (FR-4 = 4.5).

Where C ' _fo is the odd mode fringe capacitance

The C ' _fo is a factor for determining the odd mode fringe characteristic impedance of the differential drive wiring, wherein the odd mode fringe capacitance is the + V voltage of one conductor of the autonomous driving wiring -V It is the capacitance that is overestimated between two conductors when charged with voltage.

only, ε _r Is the relative permittivity (FR-4 = 4.5).

Herein, _C'fo denotes an even mode fringe capacitance, and the even mode fringe of the differential driving wiring is a factor determining the characteristic impedance. Is the capacitance observed by integrating the two conductors when one conductor is charged at + V voltage and the other conductor is at + V voltage.

here, Z _o Denotes the characteristic impedance.

The spacing between conductors T + and T- with minimum wiring width W = 0.1 [mm] for each of the total dielectric thicknesses b = 0.3 [mm], b = 0.4 [mm], b = 0.5 [mm] in the structure of FIG. Fig. 4 shows the result of calculating the odd mode impedance of Equation (1) while changing S [mm].

In Fig. 4, the odd mode impedance has a maximum point for the distance S [mm] between the conductors T + and T- and the maximum impedance is X: S: Y = 1: 2: 1 at the entire dielectric thickness b. Obtained when

Conventional Methods In Figures 1 and 2, the odd mode impedance is relatively low by about 8% to 16%. Thus, the prior art is based on prepreg-laminate-prepreg. Prepreg) or laminate-prepreg-laminate, in which the dielectric thickness ratio is generally 1: 1: 1, and each dielectric thickness is used to control odd mode impedance. In this case, the thickness of PCB is increased, which makes high density mounting and high density wiring impossible. That is, it was not possible to use thin laminates and thin prepregs in the thinning limit state.

Therefore, the problem of the prior art is firstly, even with a limit wiring width of 0.1 [mm] that can be wired by using a laminate of about 0.1 [mm] thick and two prepregs of about 0.06 [mm] thick. Odd-mode impedance of differential drive 50 [Ω] cannot be achieved.

Second, in order to fabricate the odd mode impedance of 50 [의], the thickness of Laminate should be over 0.2 [mm] at the limit wiring width of 0.1 [mm], and the thickness of the two prepregs should be about 0.2 [mm]. It should be at least [mm]. That is, the total thickness of the three-layer PCB thickness should be 0.6 [mm] or more.

An object of the present invention is a three-layer total dielectric thickness of 0.42 [mm] to 0.62 [mm] in a PCB laminated structure in the order of prepreg-laminate-prepreg or laminate-prepreg-laminate. ] Is to provide PCB laminate structure and wiring structure to realize odd mode impedance of about 50 [Ω] with minimum conductor width of about 0.1 [mm] for wiring.

In order to achieve the above object, the present invention, in the PCB laminate structure laminated in the order of prepreg-laminate-prepreg or laminate-prepreg-laminate, The ratio is 1: 2: 1, and the upper and lower parallels each convert and drive one signal at the top and bottom of the laminate with the same amplitude and opposite voltage polarity or current flow direction. It is characterized by forming a differential drive wiring of the dual-offset stripline structure.

In this case, the differential signaling / driving converts a signal into two signals having the same amplitude and opposite polarity or current flow in order to transmit a high speed electrical signal without error in a noisy environment. It is a method of driving and transmitting. The driving type includes standardization methods such as GCL (Gunning Transceiver Logic) and Low Voltage Differential Signal (LVDS), and it has strong transmission characteristics against common mode noise. It is used for signal connection with relatively long drive distance of more than 100㎐.

Accordingly, the “differential drive wiring” refers to a wire structure capable of transmitting the differential drive signal, wherein the electrical characteristics that the differential drive wiring structure should have are as follows.

-Consisting of two conductors.

The two conductors must have a dual structure, ie the electrical environment of each conductor must be identical when looking at each conductor in the middle of the two conductors,

The off mode characteristic impedance of the two conductors is uniform and the characteristic impedance value must be equal to the conjugate value of the output impedance of the "differentially driven" signal source.

The present invention is composed of a PCB laminated structure and a wiring structure for controlling the off mode impedance of the differential driving to 50 [Ω] in a thin multilayer PCB.

1 is a cross-sectional view of a laminated structure of a conventional differential drive wiring.

2 is a cross-sectional view of a laminated structure of a conventional differential drive wiring.

3 is an exemplary diagram for calculating odd mode impedance of a differential drive wiring;

4 is an exemplary diagram showing an odd mode impedance calculation result for a change in the interval S [mm] of the differential wiring.

5 is a cross-sectional view of the laminated structure of the designed differential drive wiring.

6 is a cross-sectional view of a laminated structure of the designed differential drive wiring.

* Explanation of symbols for main parts of the drawings

1: Prepreg 1 2: Laminate 1

3: Prepreg 2 4: Laminate 2

5: Prepreg 3 6: Laminate 3

11: prepreg 4 12: laminate 4

13: prepreg 5 14: laminate 5

15: prepreg 6 16: laminate 6

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

5 is a sectional view showing a laminated structure of the differential drive wiring according to the embodiment of the present invention.

As shown in FIG. 5, the PCB stacking structure has a dielectric thickness of Prepreg 4 11: a dielectric thickness of Laminate 4 12 of Prepreg 5 13. The dielectric thickness is 1: 2: 1, and the total thickness of the three-layer PCB, which is the sum of the dielectric thickness of Prepreg 4, the dielectric thickness of Laminate 4, and the dielectric thickness of Prepreg 5, is in the range of 0.42 [mm] to 0.62 [mm].

The differential driving wirings (T +, T-) have a dual-offset stripline structure that is parallel to each other up and down, and the 1: 2: 1 stack structure is a commonly used epoxy laminated numerical substrate (Fiber laminated epoxy Resin, FX-4) or FR-4 dielectrics or other dielectrics used in electronic circuit boards, and can be applied as they are. Laminate 4 with a thickness of about 0.1 [mm] and about 0.06 [mm] thick. Dielectric thickness ratio of 1: 2: 1 can be stacked by using Prepreg 4 and Prepreg 5, and the ground plane of the dual-offset stripline structure is grounded. It can be a ground plane or a potential plane.

6 is a cross-sectional view of the laminated structure of the differential drive wiring according to the embodiment of the present invention.

As shown in FIG. 6, the PCB laminate structure has a dielectric thickness of Laminate 5 (14): Dielectric thickness of Prepreg 6 (15): Dielectric thickness of Laminate 6 (16) is 1: 2: 1.

The total dielectric thickness of the FR-4 PCB 3 layer, which is the sum of the thickness of the laminate 5, the thickness of the prepreg 6, and the thickness of the laminate 6, is 0.42 [mm] to 0.62 [mm].

The differential driving wirings T + and T- have a dual-offset stripline structure that is parallel to each other vertically.

The 1: 2: 1 stacked structure can be applied to FR-4 dielectrics or other dielectrics commonly used.

The ground plane of the dual-offset stripline may be a ground plane or a potential plane.

The present invention is a minimum conductor width of about 0.1 [when thinned to a total thickness of 0.42 [mm] to 0.62 [mm] in a three-layer dielectric layer in a FR-4 PCB stack structure of Prepreg-Laminate-Prepreg or Laminate-Prepreg-Laminate. mm] has the effect of realizing an odd mode impedance of about 50 [Ω].

According to the present invention, the odd mode impedance of the differential driving is maximum when the ratio of dielectric thickness is 1: 2: 1 in the PCB laminate structure of Prepreg-Laminate-Prepreg or Laminate-Prepreg-Laminate. In the structure, odd mode impedance is increased by about 8% to 16% over the conventional method.

The present invention has an effect of stacking a dielectric thickness of 1: 2: 1 using a laminate of about 0.1 [mm] thick and two prepregs of about 0.06 [mm] thick in a limit state.

The present invention has the effect that impedance control is possible even with a limit wiring width of 0.1 [mm] or more.

Inventive dielectric thickness 1: 2: 1 laminated structure has the effect that can be applied to the FR-4 dielectric or other dielectrics commonly used.

Claims (6)

In a PCB laminate structure laminated in the order of prepreg-laminate-prepreg or laminate-prepreg-laminate, a dielectric thickness ratio of 1: 2: 1 is formed and PCB laminate structure and wiring structure, characterized in that to form a differential drive wiring above and below the laminate (Laminate). The method of claim 1, PCB laminated structure and wiring structure, characterized in that the entire dielectric thickness range of the PCB laminated structure ranges from 0.42 [mm] to 0.62 [mm]. The method of claim 1, And the differential driving wirings have a dual-offset stripline structure parallel to each other. The method of claim 3, wherein PCB grounding structure and wiring structure, characterized in that the ground plane (Ground Plane) of the dual-offset stripline (Ground Plane) is a ground plane (Ground Plane) or a potential plane (Plane). The method of claim 1, The dielectric thickness 1: 2: 1 laminated structure is a PCB laminated structure and wiring structure, which can be applied as it is to FR-4 dielectric or other dielectrics. The method of claim 1, In the prepreg-laminate-prepreg structure, a laminate having a thickness of about 0.1 [mm] in a limit state and two prepregs having a thickness of about 0.06 [mm] are used. PCB laminated structure and wiring structure, characterized in that the ratio of the dielectric thickness can be laminated 1: 2: 1.

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