533 to target 50 Ohms impedance. 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. Trace Spacing Calci 3. . Let's consider the impedance for copper at 1 MHz. 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. 0; 1 < ε r < 15 ) Select the units for all dimensions: mm mils. RF IC -> Balun N/W -> PCB antenna or Chip Antenna. Calculate the Differential Microstrip Impedance of a transmission line based on the the distance between the strips, height of the substrate, trace thickness and dielectric constant of the substrate. The PCB trace impedance increases as the width decreases. 4 mils). To manufacture controlled impedance printed circuit boards, one must be able to measure impedance. This Javascript web calculator calculates the resistance, voltage drop, and power loss of printed circuit board vias. The PCB internal/external trace resistance shall be calculated according to the following formula: R = (ρ * L / (T * W)) * (1 + α * (TAMB – 25 °C)) Where: R is the trace resistance [Ω] ρ is the resistivity parameter, whose value for copper is 1. This change in trace width leads to a change in impedance and hence causes signal reflection. Designing trace width for HDI impedance adjustments. 17mm in order to achieve this 45 ohms. 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. To use this tool, enter the values for trace thickness, substrate height, trace width, trace spacing and subtrate dielectric in the calculator above and press the "calculate" button. 510 mm, or 20 mils, and the minimum inductance is 292 nH/m. Two of them is the following one : Calculate your microstrip transmission line; Calculate your microstrip transmission line; Its gives you the impedance based on different parameters. 0. When we talk about the "impedance" of a pcb trace, we are talking about the characteristic impedance of a uniform transmission line. Calculates the current a conductor needs to raise its temperature over ambient per IPC-2152. Use the KiCad calculator (or other calculator) to estimate the trace width, associated with the distance to ground, required to get the impedance you wantA temperature rise in PCB trace width calculator is a tool or software that helps engineers and designers estimate the temperature rise in a PCB trace based on the trace width, current, and other parameters. trace width:. The size of the signal and polarity of the signal that is reflected is measured. For example on 0. For this reason, trace width is important in the design of striplines. The edge couple differential microstrip transmission line is a common technique for routing differential traces. No ground plane under Antenna. Use the following guidelines. Also, the copper thickness affects the minimum trace. We will assume here that both of the lines of the pair are identical and uniform. 5mil clearance on a 63 mil board (1. And that they have the same separation from each other along the entire length of the line. 3mm of the microcontroller), therefore i rounded the width to 0. 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. If you reduce this trace width to 19 mils, the characteristic impedance will result in about 52. This calculator determines the impedance of a symmetric differential stripline pair. 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. Cross-hatched copper plane in a flex stack-up for controlled impedance. Obviously, there is no ground on the bottom side. 7563 mm (~30 mils). Differential Impedance of. Since impedance does not care about the absolute scale, it is. The best way to calculate trace impedance is by using a trace impedance calculator. /sq. For a 0. 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. Perhaps try sharing the entire layer stackup, not just the impedance calculation portion?The simplest way for a controlled impedance is to just calculate some track width, (and gap for differential pairs), send the geometry to any PCB manufacturer and hope for the best. Note: Units do not matter for this calculation as long as they are consistent. H 1 H 1 = subtrate height 1. 378tA. Microstrip Trace Impedance vs. 0. Maximum Unambiguous Range Calculator. If your boards are to be manufactured in arrays, click on the option “Yes”. At the point of bending, the trace width is 1. Based on Figure 4, it can be concluded that as trace width changes by 0. Off the top of my head, I can think of Polar and z-calc but I never liked these. 1kOhm, 1% tolerance: Brown Black Black Brown Brown. 3 shall be used. Once the required impedance and trace geometry are determined, the next step is to calculate the trace width. Therefore, the trace height and width you choose for 1 GHz will be a slightly different impedance at 10 GHz (if you need to worry about the difference, you probably already know about the difference!)trace width: 4 mm; trace spacing: 5. New Online Microwave Impedance Calculator. Next, determine the trace. 17mm FR408 - 17um. Stripline Trace. 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. T-Match Topology. Now also calculates DC resistance with temperature compensation. PCB trace impedance can range from 25 to 125 ohms. 0mm 1. 6 4 8 12 16. 4-Layer Impedance Control Stackup. The trace width calculator uses empirical formulas based on long traces with no special heat sinking. 5mm pitch BGA. Place critical components,. 25 °C Ambient temperature 1 mm thickness 50 mm trace lengthThis tool uses formulas from IPC-2221 to calculate the width of a copper printed circuit board conductor or "trace" required to carry a given current while keeping the resulting increase in trace temperature below a specified limit. Via pad diameter (in mils) Trace/space width (in mils): This is the width of the trace and the space between them. Differential Microstrip Impedance Calculator (Using Zo) Embedded Microstrip Impedance Calculator. 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. To update trace width, select the traces of interest and use the "Route > Retrace Selected" command. For example, a 2. This calculator finds both odd and even transmission line impedance. Saturn PCB Toolkit is the best tool for PCB Designer to calculate trace width, via current calculation, Thermal dissipation, etc. Let's say I want to use L7 - GND. 024 x dT0. 44. Abrupt changes in trace width cause impedance discontinuities. They are very simple to read, and the values in. 5 mil which we can round to 14 mil. 4mm PCB for a trace width of 0. ) Increasing the trace width crazily: Or. The characteristic impedance (Z o) of coplanar waveguide with ground or microstrip lines with signal side ground plane can be calculated using the active calculator or the equations at the bottom of the page. Obviously, there is no ground on the bottom side. The Impedance Formula Editor dialog. Frequency: Frequency at which the stripline is analyzed or synthesized. Embedded Microstrip Trace. An embedded microstrip can be constructed using a microstrip with a solder mask. 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. 2 of the Microstrip Calculator, h=H1 and b=H2-H1. To use these to design for a target impedance, simply cycle through various geometric. As an example with 1 A. 2mm0. 3, a trace width of approximately 0. 1kOhm, 1% tolerance: Brown Black Black Brown Brown. For example, if you wish to input "25000000. To use this tool, enter the values for trace thickness, substrate height, trace width. ( 0. 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. If you would like to view other parameters such as trace thickness, inductance, capacitance, and effective dielectric constant, click on 👁 (eye symbol). Provide values for H, T, W and the relative permittivity of the dielectric and click the button corresponding to unknown parameter Z o to calculate its value. A trace width calculator can accurately determine various trace components, such as trace temperature, maximum current, resistance, voltage drop, and power dissipation. W is the width of the trace. Dielectric material: This is the prepreg and core materials utilized on each side of the controlled impedance trace layer. The calculator below uses Wadell’s. There are four different types of impedance used in characterizing differential trace impedances. Trace Impedance Calculator; Length Conversion; Wire Size Conversion Calculator; Inductance Conversion; See. $$Z_{0}$$ = characteristic impedance of the microstrip in ohms (Ω). You can find trace impedance calculators online or in your CAD software. trace width for a characteristic impedance of 50 Ohms on Dk = 4. 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. INPUT DATA. 0. A transmission line should have a uniform characteristic impedance. What is the width of a trace for 100 ohm impedance? The width of a trace for a 100-ohm impedance depends on the PCB material and other factors. Select a trace impedance profile over the length of the taper. Radar Calculators. Trace top width: Trace base width – 1 mil: Nan Ya Plastics NP-155F (4 to 8 layers) Core Thickness: εr: Prepreg Type: Resin Content: Nominal Thickness: εr: 0. Scientific Calculator. TransLine. Maintain consistent trace widths to ensure controlled impedance. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board thickness, copper weight, layer,. ε: Dielectric constant of the PCB material. Adequate trace width is necessary to ensure the desired amount of current can be transported without overheating and damaging your board. Dual Stripline. copper trace on a 4-layer board with 8 mil thick dielectric and Dk = 4. Impedance Calculation. 946 for silver, or 1. If you need to use differential pairs, you. Basic Calculator. They are:. Impedance Calculator; Via Impedance Calculator; Trace Width and Current Capacity Calculator; Via Current Capacity Calculator; Signal & Plane Layer Estimator; Conductor. Understanding transmission lines and controlled impedance. Explanations of signal integrity issues. 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. A trace width calculator is a tool used to calculate the width of a trace on a printed circuit board (PCB). Z0,air Z 0, a i r = characteristic impedance of air. I used a few different tools to calculate the trace impedance with different results. Select the box with the geometry that you would like to calculate. Route your single-ended and differential pair traces. TanD 0,015. 8 with 2-oz copper. 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. 7mil. For example, with a thickness of 0. PCB Trace Width Calculator. Traditional measurements of PCB impedance use a Smith chart . This procedure produces the result ( w/h) = 1. 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. 063" thick PCB, that means a trace width around 120 mil. All the impedance matching trace width calculator seem to consider that there is a ground plane on bottom. The trace width formulas are: I = 0. The impedance equations used for calculating the impedance and trace width are accessed from the Layer Stack Manager dialog, by pressing the Impedance Calculation button. To calculate the trace width for a specific impedance value, input the following data: Dielectric height; Dielectric constant of the materialIncorporate coaxial via geometry. Try This New Tool. If a signal encounters impedance discontinuity, it will generate jitters in PCBs and hampers the signal integrity. Controlling the impedance in your design is dependent on the board layer stackup you. MICROSTRIP WIDTH CALCULATOR. A coplanar waveguide with groundplane distance H = 1. Pad Stack Calculator 4. To calculate one of these quantities, the other two must be known. 92445. Where: Z0 Z 0 = characteristic impedance of the asymmetric stripline in ohms (Ω). 68. Copper foil roughness and trace width affect signal propagation and impedance. Sierra Circuits’ Trace Width, Current Capacity and Temperature Rise Calculator is an advanced PCB tool that works based on the latest IPC-2152 standard. 44, c = 0. Broadside Trace Inductance Calculator. PCB Trace Width Calculator. 414 times higher than the actual trace width. Using a calculator with an existing stackup involves a simple process to converge on a useful trace width for a target impedance. The characteristic impedance of the trace can be calculated using the below formula: Formula to calculate characteristic impedance of a PCB trace. If you know the values of any of the two parameters (conductor width, max temperature, max current capacity) it determines. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a. For example, on the left side of Figure 4, a 4-4-4 mil geometry has a differential impedance of 91 Ohms. Line Types and Impedance (Zo))Impedance (L/C)-*Lower Er Materials Net Higher Impedance Traces and Faster Propagation Times per given Trace Width & Trace-to-Ground Separation. 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. Modeling approximation can be used to understand the impedance of. 393 mm, the required trace width for this particular inductance value is w = 0. The aim of the Impedance Calculator is to support the designer in such a pre-layout design phase. If the Length, l, to diameter, d, ratio is known, you can calculate the Inductance, L, series resistance, Rs and the aspect ratio l/d is related to Q = L/Rs for a given conductor material. The tool generates odd, even, common, and differential impedance as output values. 3-in-1 calculator: temperature rise above ambient, trace width, and maximum trace current capacity; Evaluates trace resistance, voltage drop, and power loss; PCB dielectric requirement. Calculate the trace parameters for controlled impedance: Determine trace thickness, height, and length along with the dielectric constant of the material. 08mm, my trace width should be 0. Where: H is the height of the PCB above the ground plane. R. It would be nice to have a mm/mil switch including the board thicknesses. Our Impedance Calculator uses a 2D field solver to calculate near-end crosstalk based on the following equation: NEXT = V b /V a = ¼ (C mL / C L + L mL / L L). Where: Z0 Z 0 = characteristic impedance of the asymmetric stripline in ohms (Ω). The manufacturer provides a stack up as well as a 2D calculator for determining trace width: here The manufacture's calculator computes 3. The edge couple differential microstrip transmission line is a common technique for routing differential traces. A 20 mil trace will have a much greater tolerance for losing metal than a 3 mil trace would. 6 ohms. If the calculator does not provide velocity (or velocity factor), it's probably because you can use e_eff instead. surface/external edge. At 2 amps I'd worry more about voltage drops. 3. Choosing the right regulator for the power supply. For a first design (e. IPC 6012 CLASS 3/ES. 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. Select a Configuration. spacing: 0,15mm. Calculate the pcb trace impedance of. This Javascript web calculator calculates the trace width for printed circuit board conductors for a given current using formulas from IPC-2221 (formerly IPC-D-275). Stripline. H: Height (thickness) of the dielectric substrate. Trace width is an important design parameter in PCB design. The dielectric constant of a material IS slightly frequency dependent. Microstrip Trace: Embedded Microstrip Trace: Stripline Trace: Dual Stripline Trace: Geometric Parameter Definitions. 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. See below for the definition of these impedances. This calculator is designed to calculate the characteristic impedance of a broadside couple stripline (see diagram below). Since my layer thickness is 0. Once these decisions are made, a designer needs to determine the PCB trace width required to hit their required PCB transmission line impedance. This can be set to zero, but the calculated loss will not include conductor losses. 254mm. Calculate the effective dielectric constant. Next, determine the trace height/length. For differential pairs, a coupled microstrip line can work also. This is more than the to times trace width which is recommended (also read as close as possibly). It is possible to select other units. Most of the microstrip impedance calculators you’ll find online use a similar process: enter your microstrip geometry and Dk value for your PCB substrate materials, and the tool will return the impedance for your. Some of its key features are; displays insertion. Also for differential LVDS signals the tool can calculate the trace width and spacing for 100 ohm impedance for a given stack up setting. The default units for all given values, except the substrate dielectric, is in mil. The Smith Chart graphically maps S11=reflection coefficient= (ZL-Z0)/ (ZL+Z0) to Load Impedance (ZL), normalized to Z0 (source impedance = center of chart). differential trace impedance for USB (90 Ohms) on 2-layer FR4 board. as input parameters i looked up the material datasheet from my board house and got: Er 4. The Fairchild application note also says that the differential characteristic impedance of the D+ and D- lines should be 90 ohms. 8 substrates. where Z 0,surf can be computed as specified in Eq. 1 mm gives roughly 50 ohms impedance. W W = trace width. Since my layer thickness is 0. What is the width of a trace for 100 ohm impedance? The width of a PCB trace for a specific impedance depends on factors like dielectric material and thickness. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board layer, thickness, copper weight, target impedance, trace spacing (for edge-coupled pairs), and impedance trace to copper gap (coplanar waveguides). The thickness of acrylic adhesive through the rigid portion of the panel shall not exceed 10% of the overall construction. 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. Use our online tool to calculate the minimum trace width for a given current and copper weight. For example, if you wish to input "25000000", just type "25M" instead. If you need to mass produce PCB's at low cost, the minimum trace width should not be pushed too hard. This calculator finds both odd and even transmission line impedance. 2) 50 Ohms is 50 Ohms (kind of). Some of the primary design requirements of high-voltage boards are defined in IPC-2221B. A 20 mil trace will have a much greater tolerance for losing metal than a 3 mil trace would. 679 nH. For example, let us input 30°C ambient temperature, 1oz via plating, and 0. Length-tuning structures and their effects on impedance. The designer can normally enter their desired impedance, and the calculator will determine the PCB trace width needed to meet that impedance goal. Share. Stripline Impedance. This model was originally developed by analyzing trace impedance measurements using a regression model. The Calculator has the following tools: Regulators. The dialog is accessed from the PCB Editor by clicking the Impedance Calculation button in the Layer Stack Manager dialog. This tool will also provide the signal propagation delay, capacitance, and inductance per unit length. Impedance control with BGA escape. This dialog allows you to view and (if required) modifythe formulae used to calculate Impedance and Trace Width when using impedance-controlled routing. The designer can normally enter their desired impedance, and the calculator will determine the PCB trace width needed to meet that impedance goal. 08 mm: 3. For differential pairs, there is also a spacing value given. Sierra Circuits’ Trace Width, Current Capacity and Temperature Rise Calculator is an advanced PCB tool that works based on the latest IPC-2152 standard. 8. endolith. This Mantaro calculator tells me that I need a trace width of 11. 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. Hi there, and welcome to the Tools portion of EEWeb. This calculator finds both odd and even transmission line impedance. This should be provided along with the PCB material. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. Verify Against Other Design Rules. Note: The trace on the inner layer need to be much wider than the trace on the outer. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. The wider a trace is, the easier it is to fabricate. 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. PCB Trace Impedance Calculations. 98H / (. 92445. l = tr x 2 in/ns. Calculating the Impedance. The application below provides a simple way to calculate the required trace width (in mil) for a given input current and temperature. 74mm. There are many other free calculators available. 17mil is the PP thickness between impedance trace layer and reference layer,it is 0. To find what a given trace width will have a single ended or differential impedance, we can use a built in calculator from Allegro. Some of its key features include:. For controlled impedance, if the built in trace width calculator calculates that the traces need to be incredibly thin, the you need to change something else in the design, like the dielectric material or the dielectric thickness. 1< W/H < 3. Cite. β2 = 0. Some of the important things to be considered are discussed below: 1. Rise time-Max length Calci 2. In this demonstration, we’ll choose uncoated microstrip single-ended impedance calculator. 024 x dTI = 0. For your convenience, we have designed an Impedance Calculator to help you calculate the impedance and the trace width you require. 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. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. Calculate Minimum Trace Width. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. This tool includes an industry-standard field solver that is built into your PCB layer stackup. Impedance calculators or formulas like the one mentioned earlier can help determine the required trace width. Having carefully specified the board/prepreg material, I also ask for tolerances and based on that calculate the widths for eg. Yes, copper poor around your differential stripline will substantially affect the characteristic impedance. Using this tool, you can calculate 3dB bandwidth (BW), fastest signal rise time (tr), critical length (lc), maximum data transfer rate (DTR), and maximum frequency content (Fmax). For example: Yellow Violet Red Gold: 4 7 x100 ±5% = 4700 Ohm, 5% tolerance. In addition to the width and thickness of the trace, the impedance is a function of the thickness of the substrate, the dielectric constant of the substrate, and the distance of the trace from the ground plane. It uses formulas from IPC-2221 (formerly IPC-D-275). 001 inch). 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. Best is 5mils, but 4mils is OK, too. W W is the PCB trace width, in thousands of an inch (mil); A. A differential stripline pair refers to two traces located between two reference plane layers, which are routed as a differential pair. Microstrip Trace Impedance Calculator;The calculator utilizes the formula for calculating the impedance of a microstrip trace: Impedance (Z) = [87 / √(ε + 1. Here, =. Select a Configuration. It seems I could largely do without any impedance matching considerations, given what the trace lengths are. For example, if you wish to input "25000000", just type "25M" instead. I don't use less than 4 thou track widths due to the fact that a minor etching issue can introduce errors that are a large percentage of the track width. To use this tool, enter the trace width, thickness, ambient temperature, temperature rise, and the microstrip length and click the "calculate" button. Dielectric thickness. After determining the layer thickness and copper weight, you simply determine the trace width you need to use for a defined characteristic impedance. It shows the minimum trace-to-ground spacing required to. The trace geometry and material affect the controlled impedance of the trace. This tool will also compute the resistance of the microstrip, the voltage drop, and the power. a) JLC7628 Stackup:1,370. Rectangle Loop Inductance Calculator. 3 as fr4. The Sierra Circuits High-Speed Design Guide helps you design PCBs with signal frequencies from 50MHz to as high as 3GHz and beyond. Microstrip Width Calculator. This application note from Fairchild (alternative link), which is one of the top Google results, says that D+ and D- trace single-ended impedance should be 45 ohms. Even Mode Impedance (Zeven) Ω . 025mm, impedance will be thereafter changed by 5 to 6 ohm. ε: Dielectric constant of the PCB material. FR4 Impedance Distortion Calc 5. 98mil. To manufacture controlled impedance printed circuit boards, one must be able to measure impedance. 1. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. The new version includes: Additional dielectric materials. Discontinuities cause signal reflections due to impedance mismatch compromising signal integrity. When I was 12 years old, I opened a television for the first time, and that was when my passion for electronics started. Dielectric Thickness (h) Dielectric Constant (εr) Calculate. These are primarily the result of changes in the effective trace width or in the line-to-line spacing caused either by unavoidable transitions in theThe way to calculate the inductance is to first calculate impedance, and then use the impedance to calculate the trace inductance. 020 inches) for typical PCBs. 1. This design tool is based on the charts in IPC-2221. Impedance control with BGA escape routing in HDI PCBs H eff = H 1 + H 2 2 H e f f = H 1 + H 2 2. It displays the impedance of the input and output match in a 50-ohm test environment as measured on a network analyzer. where: I = maximum current in Amps dT = temperature rise above ambient in °C A = cross-sectional area in mils². The differential impedance of MIPI tracks should be 100 Ohms, not 90 (USB requires 90). The minimum. Share. The JLCPCB Impedance Calculator computes track width values and recommended stack-ups from user-input values of board thickness, copper weight, layer,. At 10 MHz, you don't need to worry about trace width/impedance unless you're using long traces and very fast rise/fall times. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. Using this application, you can quickly identify the thermal resistance of a single or a combination of vias. There are a few methods for calculating trace impedance in a circuit board as long as the dielectric constant and trace geometry are known: Use the IPC-2141. Microstrip. Round up to nearest 5 mils. , power and/or GND) constitutes a stripline layout. And the equivalent current carrying capacity equation will be: For outside visible traces the coefficient values are: K = 0. Make sure you understand the factors that influence transmission line impedance, and if needed, use a calculator to get an initial estimate of impedance before programming the required trace width as a design rule. We recommend the software from Polar Instruments if you want to get exact impedance calculation. Reference: R. thermal, and signal integrity aspects of traces on a PCB. Below is the calculation. With the RF Attenuator utility you can calculate the values of the resistors needed for different types ofColor-Code. 7 ohms; common impedance: 19. Sorted by: 8. When designing differential pairs and determining their impedance, it’s important to understand how coupling will affect the pair. IPC-2152 Calculator. T. The trace width can then be adjusted. First, the Area is calculated: Area [mils²] = ( Current [Amps] / (k* ( Temp_Rise [°C] )^b) )^ (1/c) Then, the Width is calculated: Width [mils] = Area [mils²] / ( Thickness [oz] * 1.