High-speed printed circuit board and differential wiring method thereof

A high-speed printed circuit board, comprising a wiring layer, a dielectric layer and a shielding layer laminated sequentially,

• wherein the wiring layer comprises a BGA region, a non-BGA region and two differential transmission lines disposed oppositely to each other,
• each of both the differential transmission lines comprises a first differential wire located in the BGA region, a second differential wire located in the non-BGA region and a first connection wire configured to connect the first differential wire and the second differential wire,
• the width of the first differential wire is less than the width of the second differential wire, the distance between the two first differential wires is less than the distance between the two second differential wires, the width of the first differential wire increases gradually from the BGA region to the non-BGA region, and the distance between the two first connection wires increases gradually from the BGA region to the non-BGA region,
• wherein the width of the second differential wire and the distance between the two second differential wires satisfy a formula:
• Z
• 2
• =
• 2
• *
• 87
• ɛ
• r
• +
• 1.41
• ⁢
• ln
• ⁢
• ⁢
• 5.98
• ⁢
• ⁢
• h
• 0.8
• ⁢
• ⁢
• w
• 2
• +
• t
• ⁢
• (
• 1
• -
• 0.48
• ⁢
• ⁢
• e
• -
• 0.96
• ⁢
• d
• 2
• h
• )
• wherein, Z2 is a pre-set impedance required value of the non-BGA region, w2 is the width of the second differential wire, d2 is the distance between the two second differential wires, h is the thickness of the dielectric layer, εr is the dielectric constant of the dielectric layer and t is the cooper thickness of the wiring layer.