5oz. 41)] * ln[5. 2) 50 Ohms is 50 Ohms (kind of). Geometric Parameter Definitions: JLCPCB Impedance Calculator. K = 0. Dielectric Information . β1 = 0. Sierra Circuits’ Trace Width calculator Sierra 3-in-1 trace current calculatorThe stripline impedance calculator provided below is useful for gaining an initial estimate of trace impedance for striplines. For an embedded (internal) microstrip, the formulas provided in paragraph 4. 08mm, my trace width should be 0. 6mm spacing with a trace width of 0. 254mm, spacing between both is required 0. The surface finish is neglected. 8 * W + T)]) ohms. TLDR: 1. 725. This form of microstrip is composed of two traces. For example: Yellow Violet Red Gold: 4 7 x100 ±5% = 4700 Ohm, 5% tolerance. Thank you. Matching the differential trace length and keeping the distances between the traces consistent is a common practice. /sq. This is good enough so we can now switch to the “Coupled Microstrip Line” calculator. Therefore, the IPC-2141 equations are only accurate when attempting to calculate a trace width corresponding to a 50 Ohm single-ended. For my results, I find that the minimum inductance is 292 nH per meter when ( w/h) = 1. of typical printed circuit board trace geometries. A standard trace width for an ordinary signal (no special requirements) may be in the 7-12 mil range and be as long as a few inches, but there are many things that should be considered when defining the width and length of a trace. 0mm Outer Copper Weight. , power and/or GND) constitutes a stripline layout. 2. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board layer, thickness, copper weight, target. 1 ohms; In addition to those calculation I found some other resources with some sample trace properties: Mikrocontroller. For budgetting reasons I'm tied to a stock pooling layer stackup, so I went for OSHpark's 4-layer stackup (35um copper - 0. Single Ended Impedance Ω. What is the width of a trace for 100 ohm impedance? The width of a trace for a specific impedance depends on the dielectric constant, height above the reference plane, and other parameters. This tool will also compute the resistance of the microstrip, the voltage drop, and the power. The default units for all given values, except the substrate dielectric, is in mil. ) Dramatically decrease the spacing in between differential pairs: I know:As explained in Part 1 of this series ( Circuit Cellar 367, February 2021 [3]), PCB manufacturers can propose different PCB stack-ups, and specifying a low thickness for the so-called “top prepreg” will help to reduce the trace width. Just as a sanity check, we can quickly calculate the total inductance of a trace. If copper foil. 1. Home;. PCB trace impedance can range from 25 to 125 ohms. 024, b = 0. We recommend the software from Polar Instruments if you want to get exact impedance calculation. The Differential microstrip impedance calculator is used to compute the differential (Zd) and single-ended impedance (Zo) of an edge-coupled microstrip line just by entering the width, separation and thickness of the trace along with the dielectric thickness and constant of the coupled line. The best way to calculate trace impedance is by using a trace impedance calculator. For example, a 2. Figure 3 is the plot of impedance versus trace width for the three most common types of transmission lines in PCBs—surface microstrip (SMS); buried microstrip (BMS) and centered stripline (CSL). We get a lot of questions about trace impedance and how to calculate the right trace size to hit a specific impedance in a manufacturable PCB. 2mm 1. 5mm pitch BGA. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. Embedded Microstrip Trace. Using typical values of W= 9 mil, H= 24 mil, T = 1. With Altium Designer, you can easily determine trace impedance, propagation delay, rise times, and PCB trace length. There are a few points to note about this. Equation 3. It gave me a trace width of 6. 44. Edge Coupled Stripline Differential Impedance Calculator. It would be nice to have a mm/mil switch including the board thicknesses. Column by Maurizio Di Paolo Emilio, EEWeb Editor. The Layer Stack Manager in Altium Designer can be used to easily arrange signal and plane layers in a PCB stackup and determine the impedance of traces in each layer. Obviously, there is no ground on the bottom side. 92445. We Offer a Wide Range of PCB Capabilities to Fit All of Your PCB needs. 2 High Speed USB Trace Spacing Figure 2-1 provides an illustration of the recommended trace spacing while Table 2-1 gives some trace calculation examples. Route your single-ended and differential pair traces. Review: A new PCB stack-up design and impedance calculator is available for download from Istvan Nagy (see link below). Trace Impedance Calculator. Min. The impedance value of the 20 mils trace is 37. Figure 2. 44, c =. (3 major PCBs and 2 PCB Assembly production). Enter 9. 17mil is the PP thickness between impedance trace layer and reference layer,it is 0. F-A t t enua t o rs. Reset. The calculator shows 90 ohms can be achieved using. 74mm. However, if you select “impedance control” options when getting a quote from a manufacturer, it’s important to know that this will bring additional engineering costs. This calculator computes the characteristic impedance of a twisted-pair cable based on its dimensions. 0. So Adjust trace width to match the impedance to 50 Ω Ω. This tool includes an industry-standard field solver that is built into your PCB layer stackup. The best way to calculate trace impedance is by using a trace impedance calculator. 3mm of the microcontroller), therefore i rounded the width to 0. If you want a thinner microstrip, you need to reduce the substrate height using one of the following solutions: Use a thinner 2-layer PCB, for example 0. These important design features are incorporated into your design rules, making impedance-controlled routing quick and easy. For your convenience, we have designed an Impedance Calculator to help you calculate the impedance and the trace width you require. Next, hit calculate in the results tab. The minimum. 024 x dT0. EEWeb provides a suite of Microstrip Impedance Calculators as follows: Microstrip Impedance Calculator; Embedded. For a 0. Online calculators will generally use Wadell's equations to determine the transmission line impedance numerically. 8 mils. One key thing to consider is the plating thickness is much thinner than a typical 70 microns outer layer (2oz copper) and can go as low as 16 to 25 microns, requiring a relatively large drill diameter to get enough copper to match the cross-section of the trace. They include conductor spacing, creepage, and insulation requirements. RF Wireless World. W. 025mm, impedance will be thereafter changed by 5 to 6 ohm. This tool includes an industry-standard field solver that is built into your PCB layer stackup. Using the EEWeb Microscrip Impedance Calculator, I find that with 1oz/ft^2 copper and a substrate height of 0. Access technical papers, white papers, calculators, tools and more for circuit laminates, prepreg and bonding materials. Includes information on how trace width is calculated. If the calculator does not provide velocity (or velocity factor), it's probably because you can use e_eff instead. Using the EEWeb Microscrip Impedance Calculator, I find that with 1oz/ft^2 copper and a substrate height of 0. Electromagnetic fields are part of the spectrum ranging from static magnetic fields to high-intensity gamma rays. To update trace width, select the traces of interest and use the "Route > Retrace Selected" command. Trace Spacing Calci 3. Relative Dielectric Constant ( εr ): Track Width. To calculate one of these quantities, the other two must be known. ft. In reality, we don’t need to use that trace width due to the way the traces in differential pairs will couple to each other. T=trace height . Just as important as determining an appropriate trace width for a single-ended trace is determination of an appropriate spacing between two traces in a differential pair. This tool will also compute the resistance of the stripline, the voltage drop on it, and the resulting power dissipation. 17mm in order to achieve this. R. Generally, the wagon wheel spokes do not have to be anywhere near as wide as long traces. 6mm 2. Place your components, vias, coupling capacitors. MICROSTRIP WIDTH CALCULATOR. For two layer boards, a coplanar waveguide geometry usually gives more useful dimensions than a microstrip geometry. Optimization results for example 2. It is now a major exercise to evaluate the impedance using a calculator or spreadsheet. The impedance calculations will take into account their thickness and dielectric constant. When designing differential pairs and determining their impedance, it’s important to understand how coupling will affect the pair. Here is a couple of calculator links: In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. These measurements were gathered from traces that targeted a 50 Ohm impedance. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. Here is a couple of calculator links:In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. Copper foil roughness and trace width affect signal propagation and impedance. *As Trace Width Increases, Trace Impedance Decreases (Thickness has Min Effect). It is not always possible to adjust trace length and width, hence implementing lower copper thickness is one of the feasible ways. Here, =. Now with the values shown above for the characteristic impedance and the trace width/spacing pairs, we can determine the spacing that causes the trace width for a 50 Ohm odd-mode impedance to also produce a 50 Ohm characteristic. It's open-source to download. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. Calculate trace width values based using the IPC-2221 charts by providing inputs such as current thickness and temperature values. You can’t rely on these online calculators. The designer can normally enter their desired impedance, and the calculator will determine the PCB trace width needed to meet that impedance goal. This calculator helps translating the color bars from the resistor to its value. If you are using very fast rise/fall times (regardless of frequency) and ringing is your problem, you'll need to use a trace impedance calculator, with the trace. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. 5 mm; substrate dielectric: 4. . β2 = 0. Figure 2. The IPC-2221 standard and IPC-2152 standard both include this guidance on designing for thermal reliability, and there has been some debate as to the applicability of each standard. Input your data. Differential Impedance of. Sorted by: 8. I would like to calculate the trace width of a dipole PCB antenna in order to match a 50ohm impedance. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. The width of the conducting layer is important to calculate the radiation intensity since it directly affects the bandwidth of the signal waves. Also, the copper thickness affects the minimum trace. And the equivalent current carrying capacity equation will be: For outside visible traces the coefficient values are: K = 0. Computes trace width, maximum temperature rise above ambient, and current capacity; Calculates resistance and voltage drop across a given trace length Impedance trace widths based on Bittele's standard Stackups. Use our online tool to calculate the minimum trace width for a given current and copper weight. Next, determine the trace. When crosshatching (or meshed) return paths are deployed on flex PCBs and rigid-flex boards rather than the solid copper pour return paths of traditional rigid PCBs, the calculation of impedance of stripline and microstrip PCB traces requires Hatch Impedance Calculation. Next, determine the trace width. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a. Typ e, V ref and, if needed, I a d j , select the field you want to calculate (one of the resistors or the output voltage) and enter the other two values. Use our online tool to calculate the minimum trace width for a given current and copper weight. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. 25 mm (about 10 mils) might achieve a 100-ohm characteristic impedance. Use the following equation to calculate the impedance of a stripline trace layout. Convert psi to bar, kgf/cm2 to psi, bar to kgf/cm2, and other units like pa, mmH2O, inches H2O, psf and atmosphere with the pressure measurement conversion calculator. o use this calculator, enter the parameters of the regulator . Once you know the characteristic impedance, the differential. The differential impedance you get from a typical calculator you'll find online is just an approximation; more advanced tools are needed to verify the result and set a. Microstrip Differential Impedance Formula. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. T is the thickness of the trace. Most formulas calculate impedance from width, because width is a boundary condition and it's easier to calculate forward from a boundary condition, than backwards to reconstruct it. By inputting the trace width, substrate height, dielectric constant, and substrate thickness, engineers can obtain the characteristic impedance and effective dielectric constant of a microstrip transmission line. For my results, I find that the minimum inductance is 292 nH per meter when ( w/h) = 1. differential trace impedance for USB (90 Ohms) on 2-layer FR4 board. Impedance; Signal Loss; S Parameter. The standard trace spacing for PCB design can vary based on the application, but common values range from 6 to 10 mils (thousandths of an inch) for general-purpose designs. 5mil clearance on a 63 mil board (1. To use these to design for a target impedance, simply cycle through various geometric values for the trace width until the calculator returns the target impedance. To configure the board layers and input the material widths, go to the “Design” pulldown menu and click on “Layer Stack Manager”. All the impedance matching trace width calculator seem to consider that there is a ground plane on bottom. The trace width and spacing for a certain impedance may be obtained using impedance calculator s. We recommend the software from Polar Instruments if you want to get exact impedance calculation. There is some relationship with trace width and board cost in mass production. 3 mils in the Substrate 1 Height text box, re-enter 75Ohms in the Impedance text box and click the Upper Trace Width Calculate button W2, the upper trace width resolves to 5. Features: Three-in-one calculator. PCB Trace Width Calculator. Calculate the pcb trace impedance of. A stripline is similar to the microstrip except that the flat conductor is now. You can use the following PCB impedance trace formula to calculate its circuit impedance: εr : The dielectric constant of the material;. The Calculator has the following tools:. 414 times higher than the actual trace width. Adjust the length matching to achieve propagation delay. TanD 0,015. If you need to mass produce PCB's at low cost, the minimum trace width should not be pushed too hard. A PCB impedance calculator uses field solvers to accurately approximate impedance values. Dielectric Thickness (h) Dielectric Constant (εr) Calculate. The calculator below uses Wadell’s. Trans Line. When dealing with transmission lines, Characteristic impedance is a crucial parameter, probably the most crucial that you will encounter. By formulas from IPC-2221, PCB Trace Width Calculator can estimate the width of copper PCB boards and the trace required under the given current, and at the same time keep the rise in trace temperature not to exceed the limit. However, when using EEWeb's impedance calculator, I get much different values. 2mil is the calculation trace width(the adjusted trace width,need to adjust trace width to meet impedance)Access Rogers' calculators, literature, technical papers and request samples on your smart phone or tablet through the ROG mobile app. 0mmCurrent layer:4-layer. 4mm PCB for a trace width of 0. Z0 = (60 / √εr) * ln ( (8h) / (w + s)) Where εr is the dielectric constant of the substrate material, h is the substrate height, w is the trace width, and s is the spacing between traces. Since my layer thickness is 0. A trace width calculator can accurately determine various trace components, such as trace temperature, maximum current, resistance, voltage drop, and power dissipation. Spacing with copper weight The designer can normally enter their desired impedance, and the calculator will determine the PCB trace width needed to meet that impedance goal. 24. 3W spacing between critical traces 3. For example the width of the trace(W) is 6 mils and the distance between the differential pair(A) is 8 mils. This calculator requires symmetry in the trace widths and location between plane layers. Geometric Parameter Definitions: W: trace width: T: trace thickness: H (/H1) height of trace or dielectric above return plane: C: distance between the differential stripline pair: er. The Impedance Formula Editor dialog. comments closed; Find PCB Trace Width Based on Power April 20, 2006. This online microstrip impedance calculator calculates the characteristic impedance of the microstrip (Ω), W/H ratio, and effective dielectric constant (εe) by entering the value of dielectric material relative permittivity (εr),. 020. Yes, copper poor around your differential stripline will substantially affect the characteristic impedance. 2mm1. 4 mil, εr. 15 mm spacing. It’s a three-in-one. Maintain consistent trace widths to ensure controlled impedance. Vacuum press in. The manufacturer performs a test to. ϵr ϵ r = substrate dielectric. 4-Layer Impedance Control Stackup. With copper on the sides, this is called "dual co-planar waveguide" You will need to find proper calculator for this strip configuration, and make proper corrections to you trace width and separations. To calculate the proper trace width for routing, PCB layout designers must add these parameters to the circuit's impedance. where Z 0,surf can be computed as specified in Eq. l = tr x 2 in/ns. The edge couple differential microstrip transmission line is a common technique for routing differential traces. Share. com Blog » PCB Trace Width Calculator - March 21, 2006 […] PCB Trace Width Calculator January 31, 2006 This Javascript web calculator calculates the trace width for printed circuit boards based on a curve fit to IPC-D-275. The Layer Stack Manager in Altium Designer can be used to easily arrange signal and plane layers in a PCB stackup and determine the impedance of traces in each layer. Designers often do not have access to the latest tools (or any tools in some cases) to calculate proper impedance values for their designs. Microstrip Width Calculator. Polar or rectangular grids only allow direct reading of S11. What are the limits of the trace width calculator? The formulas used in the calculator are based off IPC-2221 (formerly IPC-D-275), which covers up to 35 Amps, trace widths up. 5. This calculator not only provides the number of recommended signal layers but also assists you with PCB area, number of nets, and net density. The calculator is set up to handle an asymmetric arrangement, where traces are not centrally located in the PCB layer stack. These calculators give. The length matching of these differential pairs is important because these two lines are time-dependent or delay dependent. A higher Dk value also leads to higher dielectric loss. There are four different types of impedance used in characterizing differential trace impedances. How to achieve 100ohm impedance for HDMI differential pair on FR4? 4. One beneficial criterion is to look at the track width calculated for a 50-ohm impedance. Generally, the wagon wheel spokes do not have to be anywhere near as wide as long traces. Microstrip Trace Impedance Calculator;The calculator utilizes the formula for calculating the impedance of a microstrip trace: Impedance (Z) = [87 / √(ε + 1. These are precisely the characteristics of a pair of lines to be designated as a differential pair. Using this application, you can quickly identify the thermal resistance of a single or a combination of vias. Note: Actual impedance during manufacturing can vary by 5%/10% due to micro-level trace width changes (due to temperature variations) during the manufacturing process. 946 for silver, or 1. Therefore, there is a rise in characteristic impedance of 3. We get a lot of questions about trace impedance and how to calculate the right trace size to hit a specific impedance in a manufacturable PCB. PCB Trace Impedance Calculator. PCB Via Calculator March 12, 2006. 1 of the Microstrip Calculator using H2 in place of h, εr,eff can be computed as specified in Eq. This dialog allows you to view and (if required) modifythe formulae used to calculate Impedance and Trace Width when using impedance-controlled routing. 08mm, my trace width should be 0. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. Menu. 92. You can calculate maximum current by using the formula A = (T x W x 1. Here, the via carrying the signal is placed at the center and is surrounded by 4 ground vias. Uncoated microstrip single-ended impedance calculator. Talk to a Sierra Circuits PCB Expert today. It displays the impedance of the input and output match in a 50Ω test environment as measured on a network analyzer. 725. The next graph investigates this further. TransLine. We will also tell you by how much you can. Select a trace impedance profile over the length of the taper. T is the trace thickness [oz/ft 2], W is the trace width [mils], R is the resistance [Ω], ρ is the resistivity parameter, whose value for copper is 1. Where W is the trace width, L is the trace length, and H is the trace thickness. H (Dielectric thickness) :This means that the actual trace width for a 50 ohm line could vary from design to design. The manufacturer can then choose to make a test cupon on the frame outside the actual board and use this width for impedance control. If you know the values of any of the two parameters (conductor width, max temperature, max current capacity) it determines. There are some advantages to using a. The board thicknesses are given in mm so it is not clear that the required units for trace width appear to be mil (0. In this calculator, we will show you how to calculate the trace width of a PCB for both internal and external traces. Broadside Trace Inductance Calculator. PCB Trace Impedance Calculations. For example, if you wish to input "25000000", just type "25M" instead. 6. There is some relationship with trace width and board cost in mass production. 3mm. Coplanar Waveguide With Ground Characteristic Impedance Calculator. Sierra Circuits’ PCB Conductor Spacing and Voltage Calculator calculates the minimum spacing between two conductors if the potential difference between them is provided. It is a full-featured Excel-based tool that helps plan the PCB stack-up so that controlled impedance traces can be effectively implemented. Simpler calculators will use the less-accurate IPC-2141 equations. Traditional measurements of PCB impedance use a Smith chart . trace width and thickness, distance from other copper features, dielectric constant, and dielectric thickness or distance to reference plane of the board material all contribute to the impedance of a. Use a 4-layer board so you can achieve h ~= 0. The fabrication etching process will have a greater effect on traces that are long and isolated, so it is better to make them wider when possible. Dielectric material: This is the prepreg and core materials utilized on each side of the controlled impedance trace layer. View All Tools. 3, a trace width of approximately 0. Impedance (Z) = [87 / √ (ε + 1. Here are the steps to validate your design using Better DFM: 1. The trace width is calculated as follows: First, the Area is calculated:. Differential Impedance Ω. To use this tool, enter the values for trace thickness, substrate height, trace width. Tool calculations are based on the IPC-2152. It is important to note that in industry we can find that some differential pairs are routed this way for a strong coupling, but. It uses formulas from IPC-2221 (formerly IPC-D-275). Impedance trace widths based on Bittele's standard Stackups. While the manufacturer uses Si9000, the result does not match with what the other tools get. If impedance control is necessary, determine the trace width required to reach your impedance target. o use this calculator, enter the parameters of the regulator . (It is calculated by combining the line thickness, the dielectric constant of the board, and the distance between the line and the ground plane. Enter the values of trace width (w), trace thickness (t), trace dielectric thickness (h), overall dielectric thickness (h1), and the dielectric constant (er). High-speed PCBs operate in the range of. 6mm2. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board thickness, copper weight, layer,. If you reduce this trace width to 19 mils, the characteristic impedance will result in about 52. Once the required impedance and trace geometry are determined, the next step is to calculate the trace width. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. Just as important as determining an appropriate trace width for a single-ended trace is determination of an appropriate spacing between two traces in a differential pair. 6k 24 24 gold badges 118 118 silver badges 183 183 bronze badges. 45 for gold. Maintain consistent trace widths to ensure controlled impedance. 2. Once these decisions are made, a designer needs to determine the PCB trace width required to hit their required PCB transmission line impedance. UL Certification - Flex & Rigid Flex PCBs. To get a 50 Ohm characteristic impedance, you just have to define your trace width in the proper proportion to the H of your. The Smith Chart graphically maps S11=reflection coefficient= (ZL-Z0)/ (ZL+Z0) to Load Impedance (ZL), normalized to Z0 (source impedance = center of chart). Best is 5mils, but 4mils is OK, too. Some numbers that work: Track width 4 thou, track separation 4 thou, depth to plane 6 thou on 1 oz copper gets you pretty close according to the Saturn PCB toolkit. Should I just go with SaturnPCB's values and pray it works? The difference seems pretty severe (10%) but I guess would fall within the 25% tolerance, so. Layers contain controlled impedance that is why we need to specify these impedances in the fab notes since there can be more than one value of impedance traces per layer. You’ll have to input the following parameters and click on Calculate to view the results: PCB width; PCB length; Total number of component pins; Wiring channel width; Via pad diameter; Trace/space. Multiply the result by the square root of the ratio of (1 + (2 * h / w)) to (1 – (2 * h / w)). The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a calculated impedance according to the IPC-2141 standard. Before, working with a trace impedance calculator, one should be aware of which equations the calculation uses. Chemandy on the other hand tells me 14. 2. Note: Units do not matter for this calculation as long as they are consistent. 3 is a plot of impedance versus trace width for the three most common types of transmission lines in PCBs-- surface microstrip (SMS), buried microstrip (BMS) and centered stripline (CSL). I'm not sure which calculator to trust. 725 For IPC-2221 external layers: k = 0. For a standard FR-4 substrate with a dielectric constant of around 4. g. IPC-2152 Calculator. At times, you need to lower the copper weight to achieve a specific impedance. W=trace width. The information below details some of the key capabilities that PCBWay can offer and. 7E-6 to 2. ViaMin. spacing: 0,15mm. 906mil. Just as important as determining an appropriate trace width for a single-ended trace is determination of an appropriate spacing between two traces in a differential pair. 4 ohms; differential impedance: 90. This is found to be 10mm. ft. In this article Impedance matched. To manufacture controlled impedance printed circuit boards, one must be able to measure impedance. layout impedance. 4 mil trace thickness. 25, but gives me nice trace from the module to the stub then to. The PCB Impedance Calculator in Altium Designer. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. Use the max current (Imax) and max current density (J) to determine minimum trace width: Trace Width (mils) = Imax (A) / J (mA/mil2) Add margin of 20% for reliability. This model was originally developed by analyzing trace impedance measurements using a regression model. Next, determine the trace height/length. 1oz 2oz inner Copper Weight. Design and stackup in altium, For ex: 8 layers and impedance control of 100 ohms on layer 2 and 7 and ask your fabricator to suggest a stackup for same 8 layers and trace impedance of 100 ohms for layer 2 and 7 and compare the values. Changing the stack-up will affect the calculated trace width for impedance-controlled traces; however it will not automatically update existing traces. 1. TransLine. Coplanar Waveguide Calculator. The edge couple differential symmetric stripline transmission line is a common technique for routing differential traces.