I selected driven-modal solution for a number of modes of 2. altium. CPW T-Junction Power Divider. Edge Coupled Stripline Differential Impedance Calculator Broadside Coupled Stripline Impedance Calculator Symmetric Stripline Impedance Calculator Asymmetric Stripline. UCCALC. $$Z_{0_{diff}} = 2Z_{0_{odd}}$$ Common Impedance ($$Z_{0_{common}}$$):The impedance between. Terminated into 50 , internal to EMI receiver ** Functional equivalent circuit of a LISN, not a complete schematic ** EMI receiverWhen you use a field solver to calculate differential crosstalk, you will be using time-domain results (showing pulses input into the victim interconnect) and S-parameters to quantify broadband differential crosstalk. Take note that this assumes that the distance between the conductor and the planes is not the same for both reference planes; hence the asymmetric term. LVDS pairs need 100 ohms differential impedance. Isolation of power source noise 3. Asymmetric Stripline. USB traces must be 90 Ohms differential. Reference: R. Common mode noise also typically has equal amplitude on both line and return conductors with respect to neutral. The impedance calculator in the Allegro stack-up editor uses a static 2D field solver by default (bem2d). This calculator finds both odd and even transmission line impedance. The Si8000m adds enhanced modelling to predict the finished impedance of multiple dielectric PCB builds and also takes into account the local variations in dielectric constant on close spaced differential structures. But in your differential pair, each line will have its own characteristic impedance, lower than 100 Ohms but higher than 50 Ohms (for instance a quick computing in Saturn PCB give me 77. SLLA053B 6 Performance of LVDS With Different Cables •The line impedance must be 100 Ω ±15% for the bandwidth of 1 MHz up to the maximum frequency applied. You will need to know the thickness of the dielectric you will be using as well as the relative permittivity (dielectric constant). Coaxial Line Impedance. A printed circuit board (PCB) mechanically supports and electrically connects electronic components on a circuit board. The allegro calculator gives a value of 56. What’s more, these calculators return an accurate impedance value when as per. 2 Calculating Impedance The following equations can be used to calculate the differential impedance of the board. Change W (line width) to 3. 5. Impedance Calculation for PCB Designers - Altium. The upgrade now allows for input values significantly smaller than before. Trace Height (H) Figure 4. Z 0 = ( Z 0o * Z 0e )^0. 15 mm spacing. Dielectric Thickness: mm. Make sure the correct Layer is selected before changing this option. There's a case for having an output resistor in the driving circuit feeding a t-line with the t-line open circuited at the receive end but, any old. With the expressions for VO± from before and some algebra, an equation to calculate the output impedance of the circuitTo change the low-pass filter into a band-pass filter, add two shunt inductors: L7 in parallel with C9 and L8 in parallel with C11. This calculator is designed to calculate the characteristic impedance of a microstrip - a flat conductor suspended over a ground plane with a dielectric between them (see diagram below). A stripline resembles a microstrip line and comprises a center conductor pattern symmetrically embedded completely within a dielectric, the top and bottom layers of which are conducting ground planes. Press Analyze to see the results. Where the distance from trace to planes is not the same distance above and below. Use several of them and compare. The Smith Chart graphically maps S11=reflection coefficient= (ZL-Z0)/ (ZL+Z0) to Load Impedance (ZL), normalized to Z0 (source impedance = center of chart). Enter the new tool by Sierra Circuits. Loss is calculated as a combination of dielectric loss and conductor loss at the analyzed/synthesized length. The peaks of S21 figure show even and odd modes. 6 Coaxial Line The analytic calculation of the characteristic impedance of a transmission line from geometry is not always possible except for a few regular geometries (matching orthogonal coordinate. By inputting the known values and leaving one variable blank, you can quickly calculate the missing parameter. Stable line source impedance 2. The odd mode impedance, Z 0,o, is given by the. If you put 10 in the Line Width, the calculator calculates the single ended as well as differential impedance. To use this tool, enter the values for trace thickness, substrate height, trace width, trace spacing, and dielectric constant in the calculator above and press the "calculate" button. For instance, I want a 100 Ω controlled impedance pair, and have. The Differential Pair Impedance Calculator is a specialized tool used in electrical engineering and signal integrity analysis to determine the characteristic impedance of a differential pair of transmission lines. Unfortunately, TxLine doesn't do coplanar waveguide for differential traces. Terminating the cable with its characteristic impedance reduces reflections and increases the achievable data rate. 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. 4 Comments. Overview. Polar or rectangular grids only allow direct reading of S11. Differential Stripline Impedance Calculator. Termination: A long cable can act like a transmission line. Description. It is a transmission line most commonly found in a pcb. 8 substrates of various thicknesses. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. These important design features are incorporated into your design rules, making impedance-controlled routing quick and easy. 2. The answer lies in the spacing between the traces in the pair. This assumes ~0 trace thickness. The amplitude of this crosstalk is what this tool calculates. Most online calculators do not account for copper roughness. 62 Ohms (rounded to two decimal places) So, the Differential Impedance for this transmission line is approximately 60. Suppose you have a test transmission line that you’ve simulated with a field solver or. Otherwise you could lose data). I used some online calculator to calculate parameters of trace so it has 50 Ohm impedance. . Such a stripline is constructed with two traces referenced to the same reference planes above and below the traces with a dielectric material between them. Twisted pairs are used with balanced signals. This calculator finds both odd and even transmission line impedance, including four different types of impedance used in characterizing differential trace impedances, for microwave antennas, couplers and filters applications. See full list on resources. One of the features of this type of microstrip is the coupling betwe…Differential Stripline Impedance Calculator. The phase is mostly + 90 ∘ or − 90 ∘, indicating that Zin is mostly reactive. h = Dielectric Thickness. Equivalent impedance aroused by via parasitic inductance can be figured out by the following formula: Rising time of test signals is 500ps and its equivalent impedance is 4. I believe the 100-ohm differential equates to 50-ohm single ended because you can think of the two 100-ohm impedances as being in parallel resulting in an effective 50-ohm single-ended equivalence. GDCPW is known for its balanced configuration, which helps reduce common-mode noise and interference in high. We are now ready to calculate the microstrip characteristics. This is an important parameter in the analysis and design of circuits and systems using transmission lines. The differential impedance depends upon the D/H ratio. 90 Ohm Differential Pair: 0. The second type is common mode noise which is. The plots show the magnitude and phase of the input impedance. 004” line. Trace spacing (S) mils: Distance between planes (B) mils: Relative Dielectric constant (Er) Differential Trace Impedance: ohms: References. Broadside Coupled Stripline Transmission Line Models. EEWeb offers a free online twisted pair impedance (transmission line) calculator. Picking from the CST Cable Studio Segments Navigation Tree. Most often, the only specified requirement of a differential pair is its differential impedance. Build a model from experimental data of impedance vs. Due to the parasitic capacitance provided by the PCB substrate and the mutual inductance between. 3. It is important to determine the characteristic impedance of a twisted-pair cable because this impedance should match the impedance. We recommend the software from Polar Instruments if you want to get exact impedance calculation. Board thickness (h) = 50 micron. Type: Options are microstrip (single-ended), coplanar (single-ended), edge-coupled (differential), and dual coplanar (differential). The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo) and electrical length or. Thus, the reach of this relay is represented by the radius of the circle sketched on the R-X diagram. These are defined as the ratio of the sine wave voltage leaving a port to the sine wave voltage entering the port. The differential micro strip calculator requires some parameters. The common mode impedance is defined as the impedance of the lines connected in parallel, which is half of the even mode impedance. For a printed circuit board (PCB) this is a pair of traces, also known as a differential pair. 1. The characteristic impedance is given by: Eq. 7 ns/m (at 10 MHz). , "Characteristic Impedance of the Shielded-Strip Transmission Line," IRE. What is the characteristic impedance of twisted pair cables? 100 ohms. The K values for the various transmission lines are also copied from his Transmission Line Details windows software. View Notes. (Differential Impedance, Ohms) = Note: 1oz = 1. Moreover, this tool can also compute the signal propagation delay in inches per nanosecond (ns/in), the inductance per unit length in nano-Henrys per inch (nH/in), and. Twisted Pair Impedance (Transmission Line) Calculator. We care about maintaining the same differential impedance for the. If the width of the trace is two times the height of the dielectric (for FR4, Dk from 4 to 4. This tool helps you create a matching circuit so that optimal power transfer occurs between unmatched loads. There are four different types of impedance used in characterizing differential trace impedances. Radio Frequency Engineering Calculator. Differential pair on a reference plane for differential mode (left picture) and common mode (right picture) line impedance In addition to the four line impedance types the Impedance Calculator is also able to calculate the Coupling Factor between two traces on either the same signal layer (horizontal coupling) or between two traces on different. Click on Setup -> Constraints > Electrical Constraints Set - > Differential Pair Value - > Calculator > If you put 10 in the Line Width, the calculator calculates the single ended as well as differential impedance. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. Also, typical system configurations are taken intoLearn how to configure, define, and use your design’s impedance requirements for single-sided and differential on each layer, with Altium Designer’s Layer St. Note the single line impedance matches the spreadsheet and all is good. The differential impedance depends upon the D/H ratio. Note: valid for (w/h) from 0. That's why the numbers Mikrocontroller. Broadside-coupled Asymmetric Stripline. Measure all parameters S11, S12, S21, and S22. ZC = 0. These parameters include: Characteristic impedance (Z 0): The online calculator can compute the characteristic impedance of a transmission line, which is the ratio of voltage to current in a. The top surface and the sides of the traces are exposed to air and are referenced to a power or ground plane. Yet I got a ZDiff CPW with ground capable calculator: Differential surface coplanar waveguide with ground calculations: *0. Differential Pair Impedance (Z_diff) = (2 × Z_single) / sqrt(1 + (2d / s)) Where: Differential Pair Impedance (Z_diff) represents the characteristic impedance of the differential. It has a common mode impedance of 25 ohm and and a differential impedance of 100 ohm. 3. If the impedance of the load matches that of the source, impedance matching is not required, and the balun has a 1 : 1 impedance ratio. Take note that this assumes that the distance between the conductor and the planes is not the same for both reference planes; hence the asymmetric term. All calculations use a frequency of 1 GHz. It has been correlated many times. This transmission line calculator. It is widely used for data communications and telecommunications applications in structured cabling systems. Embedded Microstrip Impedance Calculator. Typical values for most common differential signal types are 90 ohms differential, 100 ohms differential or 120 ohms differential. 2-side PCB, one side with signals, the other with GND. Example. Dielectric constant = 3. The rules shown below are a rough approximation, and you should always check the approximation using an impedance calculator or field solver. In some cases, we can also use 75-ohm differential. This can be achieved by regulating the inner and outer diameter of the coaxial cable, along with the. 2. Phone: +44 (0)1425 489 111 / +49 (0) 8104 628 0. Dear all, I have simulated a differential pair lines (GSSG). In fact, striplines often make components such as band-pass filter's more accurately, with more symmetric roll-off and no lower cutoff frequency. the impedance seen from the line with this architecture; the diagram is shown in Figure 5. pair impedance with predifined traces’ gap. Broadside Coupled Stripline Transmission Line Models. 1. It consists of a thick core (about 42 mils) and 2 prepreg layers (7 mils each). Z0 = (L/C)^0. Design to make sure the tracks are as close together as possible and meet impedance requirements. B = separation between reference planes. They are related by the following equations: ZD = 2*ZO. These impedances are related to odd (ZO) and even model (ZE) impedances of a line. This calculator can calculate the impedance. Example 7. Sig± Differential input-signal source Z 0 Characteristic impedance of the balanced transmission line from the source to the amplifier input FDA circuit overview FDAs are broadband, DC-coupled amplifiers for balanced differential signals and have a unique ability to convert broadband, DC-coupled, single-ended signals into balanced differential. 71. Schematic of a Typical Power Line EMI Filter. Figure 3 shows the respective p and T models used to calculate the differential impedance (Z diff). Relative Dielectric Constant ( εr ): Track Width. 5. 3 Design Formulas for a Stripline. PCB designers typically need to implement impedance control for PCBs used in high-speed digital applications, such as RF communications, telecommunications, computing with frequencies higher than 100MHz, high-speed signal processing, and high-quality analog video (e. 1 7. If trace width is increased for the metal losses reduction, the single end impedance will be reduces. Click here to see the user guide of our. Read more about designing to a differential impedance specification; Read more about the six important transmission line impedance. The impedance Zo of a two-conductor transmission line, as well as the odd-mode, even-mode, differential. 0. φ = 0° if 1/2πfC = 2πfL and R = 0. The difference is in the definition of the voltage and currents in the modes as shown in Figure [Math Processing Error] 5. Tools for Designers: Impedance Calculator Try This New Tool The Sierra Circuits Impedance Calculator uses the 2D numerical solution of Maxwell’s equations for PCB. 7. 331 1 2 5. referred to as a balun. Wire Microstrip Impedance Calculator. Just enter the given values for trace thickness. Zd (Differential Impedance, Ohms) = Zo (Single Ended Impedance, Ohms) = Calculate w from ZdThe Microstrip Differential Impedance Calculator simplifies the process of determining the differential impedance of a microstrip transmission line. A great example is the surface microstrip which forms on the outer layers of the PCB. 4: Normalized even-mode and odd-mode effective. Steps in the Design of a Power Line EMI Filter •Calculate or measure the. Differential impedance between the data lines should be 90 Ω +/- 15%. 7. Enter values for W and L for a microstrip line to determine its Zo and Electrical Length. Result. We assume that the wiring is routed in the following stack. With Altium Designer, you can easily determine trace impedance, propagation delay, rise times, and PCB trace length. If you select non-inverting op-amp, the calculator will show 11. Thinking about the problem as the impedance the differential signal sees (the thing we care about) compared to the impedance the common mode signal sees (the part of the signal we typically try to eliminate in a difference amplifier) is probably more appropriate for most practical signals, and gives us a nice simple expression. The required inputs are the Dk value for the dielectric constant of the PCB substrate, and the. Pi-Matching Impedance Network Calculator. Impedance Calculators. 6), the impedance will be approximately 50 Ohms. . A microstrip is a type of transmission line in which a strip of a conducting material like copper is mounted on a dielectric material and routed to a ground plane. You will see the Differential Impedance Calculator interface with input fields for Characteristic Impedance (Z0) and Common Mode Impedance (Zc). A differential stripline pair refers to two traces located between two reference plane layers, which are routed as a differential pair. e. At low frequencies near 0 GHz, the input impedance is inductive since. 3) Trace lengths between separate LVDS pairs are most important when your receivers are very time-dependent (i. Loss Budget and Differential Impedance. Here we explore the Cadence PCB Impedance CalculatorCheck here: UltraCAD's new Differential Impedance calculator will calculate single-ended and differential impedance for the common configurations we all deal with: Microstrip. The generator and load impedances are G and ZL, respectively. This planning tab is one of the most useful tabs as it enables you to calculate the optimal data when you need a specific target impedance for single and differential pair traces. Characteristic Impedance (Z0) is the impedance of a transmission line when viewed from the perspective of the signal’s behavior. Note that the y-axis is on a logarithmic scale for clarity. For now let us focus on the single ended impedance. 6. PCB Structures / Discrete Structures / Signal Management. net Forum comes closest to the proper track width. The questions are mostly on the inner layer differential impedance item [4] below. Imagine a differential pair made of two individually screened 50 ohm cables. Our pi attenuator calculator is designed to aid you in calculating the correct values of the resistors R1 and R2, according to the diagram below. Our free impedance calculator for coplanar waveguide can help you with your design features to ensure your PCB is working as you intend. O =CHARACTERISTIC IMPEDANCE OF LINE L O = INDUCTANCE PER UNIT LENGTH C O = CAPACITANCE PER UNIT LENGTH Ro C L Z O O O = + This equation is useful only when there is a ready means for determining values per unit length. If it is different, you need to increase the length of shorter track to match with the longer track. ) and the LOW level is defined as zero. If you're trying to get your own pcb design project , you should use this tool. 6 ohms and Z even = 110 ohms for your geometry, very close to your result. Impedance Calculators used by Mantaro engineers and provided here for your use freely. Figure 1 shows the generic conduction paths of the common-mode and differential-mode noise of a dc-to-dc power supply (the DUT in an EMI lab). Impedance Calculator. Figure 1. If you do something else with the. Here we assume that the board thickness is 1. (Sorry guys, I live and I have grown up in a metric world ) With these values, Saturn PCB's off-line calculator gives 57 Ohm differential impedance. The trace impedance (single-ended) in an individual trace is normally calculated by ignoring any neighboring traces, so no coupling to other conductors in the design will be. – The impedance mismatch between vias and signal traces can cause transmission-line reflections. Single-ended impedance of each data line (with respect to GND) should be 45 Ω +/- 15. 81 mm). In terms of the characteristic impedance in line 1, mutual impedance, and current in line 1, the even mode impedance is: Even mode impedance for commonly-driven transmission lines In the case where you are routing differential pairs, then the potential between the two pairs will always be opposing (i. It is the differential impedance between them that matters. This figure shows that the differential output equals 2 × R P in parallel with the effective value of R′O = 2(VOUT± FO – VO±)/IO±. Edge-coupled Asymmetric Stripline. To calculate the external resistor values, start by calculating Z IN. 25; 1 < ε r <15 ). ). With hundreds of coaxial RF cables in-stock and ready to ship worldwide immediately, our coax capacitance calculator lets you calculate the impedance of a coax by allowing you to enter the outer diameter dielectric width and inner conductor diameter. Choose the type of op-amp, e. Choose a calculator to tune your PCB design. g. These calculators ALL use wrong naming for "differential impedance". High speed PCBs and signaling standards almost entirely use differential pairs with precise impedance. Learn how to design. INPUT DATA. This is to accommodate users who found the original ranges too limiting. The following impedance calculators are free to utilize. Grounded Differential Coplanar Wave Guide. Edge Coupled Microstrip Impedance Calculator This tool helps calculate the impedance of an edge-coupled microstrip. g. 7. Differential Trace Impedance:. Differential impedance between the data lines should be 90 Ω +/- 15%. I checked out TNT, but couldn't seem to be able to do the same with that either. 0; 1 < ε r < 15 ) Select the units for all dimensions: mm mils. The differential impedance will be a bit less than 2x the single-ended impedance. Ethernet lines are differential pairs with a differential impedance of 100 Ohms. Microstrip allows for thinner flexible. These are pre-defined topologies, such as. The skew (difference between two lines of a pair) is not specified, even though it has a significantThe differential impedance between the positive and negative trace of the transmission line is slightly less than twice the impedance of the single ended impedance. Enter values for W and L for a microstrip line to determine its Zo and Electrical Length. This technique doesn’t work for wide band requirements, but is a simple way to achieve this at a specific. where . Dimensional units:. 671; thus Z 0 = 48. The High speed protocol that is being designed for determines what the single and differential trace Impedance the traces need to meet as well as the tolerance for the impedance (e. In principle, you can calculate the inductance of a trace with a 3D field solver utility, but this is not the norm in transmission line design. This calculator is designed to find the characteristic impedance of an asymmetric stripline - a flat conductor between two ground planes. this type of termination. The impedance of a differential via pair cannot be treated with a single via impedance calculator unless the vias are spaced far apart. The differential impedance depends upon the D/H ratio. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. Determining trace impedance and propagation delay in PCB traces takes a trace length calculator and impedance profiler tool, and these features work best when they are integrated into your PCB design software. For the odd mode, the differential impedance can be obtained by setting the integration region to enclose only one of the microstrips, and the characteristic impedance of the odd mode is half the differential impedance, approximately 22 ohms. Differential impedance, Z diff, is the impedance between the two conductors. make the assumption that you will get rid of transmission line effects and calculate based on a lumped-parameter system. Microstrip Impedance Calculator. IPC 2141 Trace Impedance Calculator. 2. Asymmetric Stripline Impedance Formula. Calculate Coplanar impedance for given PCB parameters. You can interpret the name 'RLC circuit' to mean a circuit. This calculator finds both odd and even transmission line impedance. Since stripline traces are typicallyW is the Width of track. Differential impedance is the double of odd mode impedance. ). The twisted pair helps create a more uniform inductance and capacitance per unit length of wire to ensure a constant impedance, by keeping the return path as close to the signal as possible. Provide values for the four parameters H 1, H, T, W, and the relative permittivity of the dielectric. The twisted pair helps create a more. The top surface and the sides of the traces are exposed to air and are referenced to a power or ground plane. Equation 2. 9. If you have voltage and current measurements from a circuit network, you can calculate the network’s characteristic impedance using Ohm’s law. Equation 3, which was developed by Martin Marietta in the mid 1980s, is a method for predicting the impedance of buried microstrip transmission lines. 5Ω, times 18 mA = 400 mV. High-speed designs carry a requirement for controlled impedance, crosstalk control, and the need for interplane capacitance. The pair of conductors can be wires in a twisted-pair. e. While commonly constructed using printed circuit boards, this structure can also be built using other materials as long as there is a conductor separated from. In both cases, you’ll need to enter your stackup information into the calculator to get accurate results. New Online Microwave Impedance Calculator. The original source of formula is IPC-2141: Controlled Impedance Circuit Boards and High-Speed Logic Design, April 1996. When dealing with differential pairs, thi. Picking it interactively in the 3D view and. A microstrip width calculator can calculate the width of a microstrip. From here, we can see that there are specific stack-ups where a CPW and a microstrip/stripline will have 50 Ohm impedance and the same trace width, even though the ground clearance is quite close clearance to the trace in the CPW. Coplanar Waveguide With Ground Characteristic Impedance Calculator. In high-speed digital protocols, data is sent over single-ended traces in a PCB that is impedance controlled; each individual trace is designed to have a specific impedance. 5 to 4. 2. Spurious Free Dynamic Range Calculator. Notes:. which is the characteristic impedance of the system. The required values are trace thickness, substrate heights, trace width, and subtrate dielectric in the calculator above and press the "calculate" button. (Not reasonable in general, but sometimes used for test and measurement purposes). Synthesize the physical parameters (length and width) for the λ/4 CPW line with impedances of Z0 and √2 Z0. ; This formula allows us to determine the. The free on-line trace-impedance calculator tool[5] provided an estimate of the parasitic capacitance. 5oz inner copper, 8 mil trace spacing) and a target differential impedance of 100 ohms, JLC's calculator suggests a trace width of 8. In a matched system, when the load impedance ZL matches theAltium Designer includes a PCB trace impedance calculator, PCB trace width calculator under IPC 2152, and a plethora of other important design tools. Try TNT or TxLine. In the special situation for which there is no coupling to ground, Differential impedance equals the Characteristic. 5. 25Distance units: Substrate Height, H Trace Width, W Thickness, TThe differential impedance depends upon the D/H ratio. Calculating Width and Spacing Comparing Width and Spacing for Differential Microstrips The concept and implementation of differential impedance are. Modeling approximation can be used to understand the impedance of the edge couple differential stripline transmission line. Second-order differential equation complex propagation constant. So now you have the impedance looking into an infitely long line of cable. The formula used in this calculator is an approximation for the characteristic impedance of a coplanar waveguide: scssCopy code. The original idea of USB physical drivers was a 18-mA current source into a transmission line terminated with 45Ω on both ends. So, I am trying to figure out how to use Kicad’s PCB Calculator for “Coupled Microstrip Lines”: I’m unsure about what a couple of the parameters mean and can’t find. Impedance control in flex stack-ups is essential to reduce signal reflections and achieve dependable signal integrity. (Sorry guys, I live and I have grown up in a metric world ) With these values, Saturn PCB's off-line calculator gives 57 Ohm differential impedance. 347 e -2. atlc. g. •The propagation delay time on the line should not exceed 5. The following formulas are used for the calculation: φ 90° if 1/2πfC < 2πfL and R = 0. Because input impedance only depends on the. Relative Dielectric Constant ( εr ): Track Width (S): mm. , equal in magnitude but opposite in. Copper thickness (t) = 18 micron. INPUT DATA. Using this calculator, I found 100 Ohms by giving 9 mils of track width, 5 mils of track separation, 8 mils of dielectric (prepregs usually have a dielectric constant of 3. In differential pairs, each trace in the pair carries the same magnitude, but opposite polarity. It shows the minimum trace-to-ground spacing required to. Safe connection of measuring equipment 4. Pi and Tee Attenuator Pad. If the transfer impedance is known, then you can calculate the differential impedances from single-ended measurements. Email: [email protected]. 25Distance units: Substrate Height, H Trace Width, W Thickness, TThe differential impedance depends upon the D/H ratio. Single-ended impedance of each data line (with respect to GND) should be 45 Ω +/- 15.