A common differential (dynamic) impedance calculation model

Differential line impedance models are similar to single-ended lines, with the biggest difference being that the differential line impedance model has one more parameter S1, the distance between the differential impedance lines (note the distance between the center points of the line). 

1.edge-coupled Surface microstrip 1 b

Scope of application:

The

differential impedance calculation of the outer barrier welding (pre-weld). This model is more commonly used than the following model, which contains solder resistance. Due to the outer layer, the copper thickness of the wire is the substrate copper thickness + plating copper thickness (when using core);
Or when the surface is using a separate copper foil, the thickness of the finished copper foil.

Parameter description:

H1: Line layer to closer reference layer Vcc/gnd distance W2: Impedance line wide W1: Impedance line width S1: The distance between the difference impedance line (note is the distance between the center point of the line) T1: Impedance line copper thickness = substrate copper thickness + plating copper thickness ER1: dielectric layer dielectric constant

2.edge-coupled coated Microstrip 1 b

Scope of application:

differential impedance calculation of the outer resistance welding. Due to the outer layer, the copper thickness of the wire is the substrate copper thickness + plating copper thickness (when using core), or when the surface using a separate copper foil, the finished copper foil thickness.

Parameter description:

H1: Line layer to closer reference layer Vcc/gnd distance W2: Impedance line wide W1: Impedance line width S1: The distance between the difference impedance line (note is the distance between the center point of the line) T1: Impedance line copper thickness = substrate copper thickness + plating copper thickness ER1: dielectric layer dielectric constant CER1: Solder resistance dielectric constant C1: substrate solder resistance thickness C2: line surface resistance welding thickness (after processing) C3: Difference impedance between line resistance welding thickness

3.edge-coupled Embedded microstrip 1b1a
Scope of application:

The

second line layer impedance calculation with the outer layer, such as a 6-layer board, L1, L2 are the line layer, L3 is the reference layer (GND/VCC), then the L2 layer impedance calculation using this method. In addition, due to the inner layer, the copper thickness of the line layer is the substrate copper thickness (Core), rather than the surface of the microstrip wire substrate copper thickness + plating copper thickness, this should be noted.

Parameter description:

H1: The media thickness between the outer and the reference layer Vcc/gnd H2: the thickness of the outer to the second line layer and the second layer of copper thick W2: Impedance line width W1: Impedance line width S1: The distance between differential impedance lines (note the distance between the line center points) T1: Impedance line Copper thickness = Substrate copper thickness ER1: Dielectric dielectric constant (the dielectric constant between the line layer to the adjacent reference layer) ER2: Dielectric layer dielectric constant (between the outer layer and the second line between the dielectric constants)

4.edge-coupled Offset stripline 1b1a
Applicable range: edge-coupled Offset stripling--Differential Asymmetric ribbon line 1b1a.

The

impedance calculation of the line layer sandwiched between two gnd (or VCC), that is, a line layer whose upper and lower layers are reference layers, the impedance calculation for this line layer applies to this model. Note that this is a strip line. In addition, due to the inner layer, the copper thickness of the line layer is the substrate copper thickness (Core), rather than the surface of the microstrip wire substrate copper thickness + plating copper thickness, this should be noted.

Parameter description:

H1: The distance between the line layer and the closer reference layer VCC/GND (note differs from the media thickness above) H2: The distance between the line layer and the farther reference layer VCC/GND (note different from the media thickness above) W2: Impedance line wide W1: Impedance line width S1: The range between the differential impedance lines ( Note is the distance between the center points of the line) T1: impedance wire copper thickness = substrate copper thickness ER1: dielectric layer dielectric constant (between the line layer to the closer reference layer) ER2: Dielectric layer permittivity (dielectric constant between the line layer and the farther reference layer)

5. edge-coupled Offset stripline 1b2a
Scope of application:

two reference layer (VCC/GND) clamp two line layer impedance calculation, such as a 6-layer plate, L2, L5 layer for VCC/GND, line layer L3, L4 impedance calculation. Use this method. In addition, due to the inner layer, the copper thickness of the line layer is the substrate copper thickness (Core), rather than the table

layer Microstrip wire substrate copper thickness + plating copper thickness, this point to note.

Parameter description:

H1: Line Layer 1 to the closer reference layer VCC/GND distance H2: Line Layer 1 to the line Layer 2 spacing + line Layer 1 and the line Layer 2 copper thick H3: line Layer 2 to the farther reference layer vcc/gnd distance W2: Impedance line wide W1: Resistance line width S1: The distance between the differential impedance line ( Note is the distance between the center points of the line) T1: Impedance line copper thickness = substrate copper thickness ER1: dielectric layer dielectric constant (line layer 1 to the closer reference layer between media constants) ER2: Dielectric layer dielectric constant (line layer 1 to the line Layer 2 media constant)

ER3: Dielectric dielectric constant (dielectric constant between the line layer 2 to the farther reference layer)

6.edge-coupled Offset stripline 1b1a2r

Scope of application:

two reference layer (VCC/GND) clamp two line layer impedance calculation, such as a 6-layer plate, L2, L5 layer for VCC/GND, line layer L3, L4 impedance calculation. Use this method. In addition, due to the inner layer, the copper thickness of the line layer is the substrate copper thickness (Core), rather than the table

layer Microstrip wire substrate copper thickness + plating copper thickness, this point to note.

Parameter description:

H1: Line Layer 1 to the closer reference layer VCC/GND distance H2: Line Layer 1 to the line Layer 2 spacing + line Layer 1 and the line Layer 2 copper thick H3: line Layer 2 to the farther reference layer vcc/gnd distance W2: Impedance line wide W1: Resistance line width S1: The distance between the differential impedance line ( Note is the distance between the center points of the line) T1: Impedance line copper thickness = substrate copper thickness ER1: dielectric layer dielectric constant (line layer 1 to the closer reference layer between media constants) ER2: Dielectric layer dielectric constant (line layer 1 to the line Layer 2 media constant)

ER3: Dielectric dielectric constant (line layer 2 to farther reference inter-layer dielectric constants) REr: The dielectric constant of a filler resin between differential impedance lines

7.edge-coupled coated Microstrip 2B and edge-coupled Offset stripline 2b2a

7.1 edge-coupled Coated microstrip:

For example a 4-layer board, L1 layer needs to do impedance control, L2 layer for the line layer, L3 layer for VCC/GND.

7.2 edge-coupled Offset stripline 2b2a:

For example, a 8-layer board, L4 need to do impedance control, L2, L6 layer for the reference layer VCC/GND,L3, L5 for the line layer.

A common differential (dynamic) impedance calculation model