They are very simple to read, and the values in. Z0,air Z 0, a i r = characteristic impedance of air. It gave me a trace width of 6. 7563 mm (~30 mils). g. 54cm trace at the non-inverting input of a high-speed op-amp will result in 29nH stray inductance. of typical printed circuit board trace geometries. The calculator is set up to handle an asymmetric arrangement, where traces are not centrally located in the PCB layer stack. The surface finish is neglected. 2-side PCB, one side with signals, the other with GND. MICROSTRIP WIDTH CALCULATOR. Different board materials, the dielectric layer thicknesses and constant (Dk), and the thickness of the metal traces all need to be part of the calculations. Sierra Circuits’ Via Thermal Resistance Calculator is an advanced PCB design tool that expedites the process of designing thermal vias. Disclaimer: Our trace width calculator tool is exclusively designed to evaluate optimum trace width, maximum trace current, and temperature rise above the ambient required for a feasible PCB design. For budgetting reasons I'm tied to a stock pooling layer stackup, so I went for OSHpark's 4-layer stackup (35um copper - 0. 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 second part shows the impedance table which gives the details of impedances on different layers along with the trace widths and trace spacing. 1kOhm, 1% tolerance: Brown Black Black Brown Brown. Menu. 7mil. The other option is to use a calculator based on either IPC-2152 or IPC-2221 standards. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. 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. Trace Thickness (T) 2. Adjust the length matching to achieve propagation delay. Online calculators will generally use Wadell's equations to determine the transmission line impedance numerically. A higher current requires thicker traces while a thicker. 2. For more accurate numbers, you can use a trace impedance calculator online. Trace impedance is dependent on not only. The rigid-flex fab notes must consist of rigid notes and flex notes. Just enter the given values for trace thickness, substrate heights, trace width and substrate dielectric in the calculator above and press the "calculate" button. 5x trace width for the drill diameter, and drill + trace width for the pad. If a signal encounters impedance discontinuity, it will generate jitters in PCBs and hampers the signal integrity. T T = trace thickness. Then, using a standard PCB trace impedance calculator or using the formulas in a textbook, you’ll find that the required trace width is 13 mils. Spacing with copper weightSierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. Microstrip Trace: Embedded Microstrip Trace: Stripline Trace: Dual Stripline Trace: Geometric Parameter Definitions. 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. The tool will display the following results in red at the bottom: Recommended signal layersPCB Trace Impedance Calculator. 63mils via height. 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. Keep in mind that the reactance of the ideal inductor has the same magnitude as its impedance. 15 mm spacing. F-A t t enua t o rs. There are four different types of impedance used in characterizing differential trace impedances. Since impedance does not care about the absolute scale, it is. I used the impedance calculator in Altium with the trace type selected as "single" which I believe is Microstrip. Microstrip Trace Impedance vs. PCB Trace Impedance Calculator. 8 mils. To manufacture controlled impedance printed circuit boards, one must be able to measure impedance. 17mm FR408 - 17um. Summary. The Fairchild application note also says that the differential characteristic impedance of the D+ and D- lines should be 90 ohms. 510 mm, or 20 mils, and the minimum inductance is 292 nH/m. calculate the impedance and capacitance of PCB traces. There are four different types of impedance used in characterizing differential trace impedances. 5 mils and spacing of 4. Calculations are based on formulae from IPC-2221. where Z 0,surf can be computed as specified in Eq. 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). Off the top of my head, I can think of Polar and z-calc but I never liked these. Let us consider the via diameter as 10mils and temperature rise above ambient as 40°C. IPC-2152 Calculator. Reset. 17mm in order to achieve this 45 ohms. 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. . For differential pairs, a coupled microstrip line can work also. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. You can find trace impedance calculators online or in your CAD software. ϵr ϵ r = substrate dielectric. One of the most common inquiries that we encounter at Bittele electronics are regarding our standard trace widths for a given board thicknesses and copper weight. Where, εr is the dielectric constant of the material (as per the datasheet) H is the height of the trace above ground. Best is 5mils, but 4mils is OK, too. Here, =. It’s a three-in-one. H 2 H 2 = subtrate height 2. 2mm0. In the case where there is a plane present, a correction factor is applied to determine the required copper. F-A t t enua t o rs. Using the EEWeb Microscrip Impedance Calculator, I find that with 1oz/ft^2 copper and a substrate height of 0. Where: Z0 Z 0 = characteristic impedance of the asymmetric stripline in ohms (Ω). For example, on the left side of Figure 4, a 4-4-4 mil geometry has a differential impedance of 91 Ohms. For differential pairs, there is also a spacing value given. 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. W is the width of the trace. 2mm 1. And that they have the same separation from each other along the entire length of the line. Select a Configuration. H (Dielectric thickness) :This means that the actual trace width for a 50 ohm line could vary from design to design. The tool implements numerical solutions of Maxwell’s equations to render accurate and consistent results. Track Width. Differential Impedance Ω. Based on Figure 4, it can be concluded that as trace width changes by 0. Once the routing is done check the trace width. 2, the resulting trace width required for 50 Ohm impedance would be 15. The manufacturer can then choose to make a test cupon on the frame outside the actual board and use this width for impedance control. 2mm1. Microstrip Trace Impedance Calculator;The calculator utilizes the formula for calculating the impedance of a microstrip trace: Impedance (Z) = [87 / √(ε + 1. 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. Sierra Circuits can: Help you with your controlled impedance stack-up. Through PCB impedance control, the impedance offered by the trace to an alternating current signal can be predetermined. The characteristic impedance of the trace can be calculated using the below formula: Formula to calculate characteristic impedance of a PCB trace. 25mm between the differential pair with a width of 0. Obviously, there is no ground on the bottom side. when i use Saturn PCB design to match the differential impedance to 100ohms i get 0. No ground plane under Antenna. Understanding transmission lines and controlled impedance. Impedance lines should not be patched, and any gap in the signal trace should not exceed 10%. 8 with 2-oz copper. 035mm and Er = 4. 5mil clearance on a 63 mil board (1. Reference: R. The trace width can then be adjusted. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. There are some advantages to using a microstrip transmission line over other alternatives. as input parameters i looked up the material datasheet from my board house and got: Er 4. 45 for gold. 378 [mils/oz/ft. 3mil seems like a substantial enough difference. And that is how you can easily calculate the impedance and trace. T is the thickness of the trace. 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. differential trace impedance for USB (90 Ohms) on 2-layer FR4 board. Height: Height of the substrate. Sorted by: 8. The required inputs are the Dk value for the dielectric constant of the PCB substrate, and the. Our current online trace width calculator is useful for clients who need to calculate the minimum/maximum trace widths for. Pressure Conversion. In order to get 100 Ohms differential, the line width must be. Loop Inductance Calculator. Altium will assume you want to confine the signal to your trace (and ground plane), rather than cause radiation. Different board materials, the dielectric layer thicknesses and constant (Dk), and the thickness of the metal traces all need to be part of the calculations. Use our online tool to calculate the minimum trace width for a given current and copper weight. 74mm. 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),. H: Height (thickness) of the dielectric substrate. Conversely, if the spacing between two conductors is given then the maximum potential difference that can be allowed between them is computed. The trace geometry and material affect the controlled impedance of the trace. For example, when a trace bends at an angle of 90 degrees, trace width changes significantly. Dielectric thickness. Trace impedance is dependent on not only. Calculations are based on formulae from IPC-2221. TransLine. 725. Select the trace under properties. The information should include the impedance value, the trace width, the spacing for. 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. A trace is a conductive path on a PCB that carries electrical signals between components. To calculate the proper trace width for routing, PCB layout designers must add these parameters to the circuit's impedance. 7E-6 to 2. IPC-A-600 Inspectors. Sierra Circuits Impedance Calculator. You can also calculate the accurate drill diameter, via to via spacing, and the thermal vias that. 0. and anded up with: so width: 0,47mm. $$Z_{0}$$ = characteristic impedance of the microstrip in ohms (Ω). 0mm Outer Copper Weight. the current table. The PCB designer needs to ensure that noisy digital circuit power supplies are separated from critical analog circuit power supplies and circuits. 44, c =. β2 = 0. It is not always possible to adjust trace length and width, hence implementing lower copper thickness is one of the feasible ways. The trace width (0. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. INPUT DATA. The IPC-2141 trace Impedance calculator will help make initial design easier by allowing the user to input basic parameters and get a. Via impedance Via step response Via DC resistance Via impedance Via resonant frequency Via thermal resistance Via voltage drop Via power dissipation in dBm. The trace impedance (Z) of a PCB trace can be calculated using the formula for microstrip transmission lines: Z = (87 * Log10 [ (2 * H) / (0. value, (of 100 Ω ± 15% for HDMI), and assumes either higher or lower impedance values. PCBWay is a professional quick-turn PCB prototyping, PCB Assembly and low-volume production manufacturer located in Shenzhen China. So, the dielectric at my 5-6GHz frequency range is 3. Edge Coupled Stripline Differential Impedance Calculator. 5mm). So just set the trace width constraint in your PCB router to 13 mils, and your routes will all be precisely 50 Ohms. 92445. ft. You can find trace impedance calculators online or in your CAD software. Impedance trace widths based on Bittele's standard Stackups. It is not always possible to adjust trace length and width, hence implementing lower copper thickness is one of the feasible ways. T=trace height . RF Wireless World. The differential impedance of MIPI tracks should be 100 Ohms, not 90 (USB requires 90). 6mm pcb thickness ) with 8 mil trace width, 8 mil trace spacing , 1. 18. You can use the following PCB impedance trace formula to calculate its circuit impedance: εr : The dielectric constant of the material;. There are many factors that go into calculating the width of an impedance controlled trace. 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. /sq. This calculator determines the impedance of a symmetric differential stripline pair. Dual Stripline. This tool includes an industry-standard field solver that is built into your PCB layer stackup. The PCB design tools in Allegro include an impedance calculator that will help you size your traces so that they have defined characteristic impedance. View All Tools. PI Network Impedance Matching. 5 oz. It is a full-featured Excel-based tool that helps plan the PCB stack-up so that controlled impedance traces can be effectively implemented. Try This New Tool. It includes calculations for trace width, impedance, current-carrying. Controlled differential impedance starts with characteristic impedance. Microstrip Impedance Calculator. When dealing with transmission lines, Characteristic impedance is a crucial parameter, probably the most crucial that you will encounter. 1oz 2oz inner Copper Weight. The calculator then uses a formula to calculate the width and spacing of the trace or transmission line required to achieve the desired characteristic impedance. For a rough estimate, it might be in the range of 10 to 20 mils (0. TransLine. per sq. Calculates the current a conductor needs to raise its temperature over ambient per IPC-2152. Relations bewteen Trace Width, Dielectric Thickness, Trace height, Er => Calculate Impedance. Share. 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. β1 = 0. layout impedance. Microstrip Trace Impedance vs. It is possible to select other units. h : Trace thickness, t (input3) : Impedance, Zo (input4) : OUTPUT Microstrip Width, mils : EXAMPLE: Inputs: Relative dielectric permittivity = 3. 6mm 2. trace width for a characteristic impedance of 50 Ohms on Dk = 4. For a first design (e. via stitching to GND plane. 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. This calculator determines the impedance of a symmetric differential stripline pair. 414 times higher than the actual trace width. 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. At the point of bending, the trace width is 1. The best high-speed performances are usually accomplished if the width of the component is close to the track width. There are several formulas and online calculators that can be used to calculate trace width. Select a trace impedance profile over the length of the taper. Dielectric Information . We will also tell you by how much you can. Pulse Repetition Frequency (PRF) Calculator. You can then check this PCB trace width against. Uncoated Microstrip Differential Pair Impedance Calculator . com PCB Trace Impedance Calculator. W: Width of the microstrip trace. For the signal trace of width W and thickness T, separated by distance H from a ground (or power) plane by a PCB dielectric with. For example on 0. 6mm) That should give the traces around 90 Ohms differential impedance according to the PDF, but when I try to input it to my impedance calculator (Saturn PCB toolkit V7. The calculator below uses Wadell’s. Route your single-ended and differential pair traces. Keep signal traces perpendicular to adjacent layersReflections from impedance changes in the impedance of a trace under test are measured. Step 3: Calculate the Trace Width. Access. W: trace width: T: trace thickness: H (/H1)The trace width calculator uses empirical formulas based on long traces with no special heat sinking. 98H / (. EEWeb provides a suite of Microstrip Impedance Calculators as follows: Microstrip Impedance Calculator; Embedded Microstrip Impedance. If you reduce this trace width to 19 mils, the characteristic impedance will result in about 52. This can be set to zero, but the calculated loss will not include conductor losses. 17mm in order to achieve this. There are four different types of impedance used in characterizing differential trace impedances. of typical printed circuit board trace geometries. 49mil trace width. Qorvo Calculators and Design Tools MatchCalc Qorvo MatchCalc is a free downloadable RF/microwave matching calculator with ideal tunable passive components. For example, let us input 30°C ambient temperature, 1oz via plating, and 0. This model was originally developed by analyzing trace impedance measurements using a regression model. 22mm. Cite. A PCB impedance table will provide the trace width required to have a target impedance value on a standard stackup. To use this tool, enter the trace width, thickness, ambient temperature, temperature rise, and the microstrip length and click the "calculate" button. 393 mm, the required trace width for this particular inductance value is w = 0. 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. Correct track impedance is the first point usually made in various online sources I've found on the subject, so I tried to get the microstrip impedance calculator to get as close the desired 100 Ohm. It is important to note that in industry we can find that some differential pairs are routed this way for a strong coupling, but. 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. High-speed PCBs operate in the range of. A coplanar waveguide with groundplane distance H = 1. When I was 12 years old, I opened a television for the first time, and that was when my passion for electronics started. At times, you need to lower the copper weight to achieve a specific impedance. A PCB. The impedance Z 0 of a transmission line consisting of a circular signal conductor having a diameter d and centered between parallel ground planes separated by a distance h is given by: Eq. The Track Width tool calculates the trace width for printed circuit board conductors for a given current and temperature rise. Tool calculations are based on the IPC-2152. The edge couple differential microstrip transmission line is a common technique for routing differential traces. 001 inch). The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. These calculators give. Place critical components, such as microcontrollers or high-speed ICs, close to the power source to avoid trace stubs. (It is calculated by combining the line thickness, the dielectric constant of the board, and the distance between the line and the ground plane. R. 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. We Offer a Wide Range of PCB Capabilities to Fit All of Your PCB needs. The surface finish is neglected. 378tA. A stripline is similar to the microstrip except that the flat conductor is now. Let's calculate the trace thickness and trace spacing- Som with a 15% tolerance and 90 Ohms targeted impedance, the conductor width required 0. One of the most common inquiries that we encounter at Bittele electronics are regarding our standard trace widths for a given board thicknesses and copper weight. 28. Column by Maurizio Di Paolo Emilio, EEWeb Editor. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. The impedance depends on the net width, the net height, the board type and so one. 048 x dT0. IPC 2141 Trace Impedance Calculator. This tool includes an industry-standard field solver that is built into your PCB layer stackup. 3. It mentions formula or equations used in this Microstrip Width Calculator. H 1 H 1 = subtrate height 1. For your convenience, we have designed an Impedance Calculator to help you calculate the impedance and the trace width you require. This tool will also compute the resistance of the stripline, the voltage drop on it, and the resulting power dissipation. Pick a signal frequency for your taper. 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. Basic Calculator. To calculate the trace width/spacing, I used SaturnPCB. 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. It shows the minimum trace-to-ground spacing required to. Trace Impedance Calculator. I would like to calculate the trace width of a dipole PCB antenna in order to match a 50ohm impedance. 7E-6 [Ω · cm] L is the trace length [cm] T is the trace thickness [cm] W is the trace width. 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. Rise time-Max length Calci 2. 024, b = 0. This flow is outlined below. , Why do you expect to see frequency in a trace impedance calculator? The type of calculator offered by JLCPCB is to calculate. Differential Impedance of. It supports both balanced and unbalanced lines. The formula used in this calculator is an approximation for the characteristic impedance of a coplanar waveguide: scssCopy code. 015mm. 0mm1. 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. Length-tuning structures and their effects on impedance. This tool will also provide the signal propagation delay, capacitance, and inductance per unit length. Access. Calculate the trace parameters for controlled impedance: Determine trace thickness, height, and length along with the dielectric constant of the material. 9E-6. 048, b = 0. Also for differential LVDS signals the tool can calculate the trace width and spacing for 100 ohm impedance for a given stack up setting. 254mm, spacing between both is required 0. 8mm1. Features: Three-in-one calculator. Enter the relative permitivity, width of the trace, the ground plane spacing, and the substrate thickness to calculate the characteristic impedance. Therefore, the IPC-2141 equations are only accurate when attempting to calculate a trace width corresponding to a 50 Ohm single-ended. I celebrated my 18th birthday playing with an oscilloscope — a gift from my grandparents. How to achieve 100ohm impedance for HDMI differential pair on FR4? 4. Call us: +1 (800) 763-7503. The calculator shows 90 ohms can be achieved using. Calculates the characteristic impedance and per-unit-length parameters. 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. PCB Trace Width Calculator. Cross-hatched copper plane in a flex stack-up for controlled impedance. See below for the definition of these impedances. There are many calculators available online, as well as built into your PCB design software. These important design features are. While the manufacturer uses Si9000, the result does not match with what the other tools get. Using the built-in Simbeor ® impedance calculator, the PCB editor's Layer Stack Manager calculates the trace width needed to deliver the specified impedance. 44. For a 1 inch trace, this value would have a total inductance of ~7. The wider a trace is, the easier it is to fabricate. This change in trace. Since impedance traces are not specified here, the manufacturing focus is completely upon building a board within +/-10% tolerance of the specified dielectric thickness from layer to layer. You can better understand your calculator results by becoming familiar with the following formulas. This procedure produces the result ( w/h) = 1. W: trace width: T: trace thickness: H (/H1)You can use our calculator to determine various trace components, such as trace temperature, maximum current, resistance, voltage drop and power dissipation. This Javascript web calculator calculates the resistance, voltage drop, and power loss of printed circuit board vias. Just enter the given values for trace thickness, substrate heights, trace width and subtrate dielectric in the calculator above and press the "calculate" button. Discontinuities cause signal reflections due to impedance mismatch compromising signal integrity. The following formula is used to calculate the differential impedance of a microstrip: To calculate the differential impedance of a microstrip, divide the characteristic impedance of the microstrip by 2. 048. Trace Spacing Calci 3. The new version includes: Additional dielectric materials. Matching the differential trace length and keeping the distances between the traces consistent is a common practice. 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. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. Balun's Single Ended Impedance = 50 Ω Ω. 25 mm (about 10 mils) might achieve a 100-ohm characteristic impedance. You can’t rely on these online calculators. H (Dielectric thickness) : This means that the actual trace width for a 50 ohm line could vary from design to design. 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. (3 major PCBs and 2 PCB Assembly production). The application will often drive the trace widths and types in a PCB design and at a certain point, there is. For example, if you wish to input "25000000", just type "25M" instead. Saturn PCB Toolkit is the best tool for PCB Designer to calculate trace width, via current calculation, Thermal dissipation, etc. Fabricators give trace impedance tables as guides to designers that need to implement controlled impedance in their PCBs. 6 4 8 12 16. EM fields are an important consideration while designing PCBs and require a field solver to predict their effect on the circuit board. The inductance of a broadside coupled trace is easy to calculate. 78 mils; with the lower trace width etch factor at 1 mil the lower trace width will therefore be 6. Layout designers will use a PCB impedance calculator to solve the electromagnetic field and deliver accurate trace variables for fabrication. 98H / (. The characteristic impedance of your microstrips is determined by the trace width for a given layer stackup. Dielectric Height (H1) ( mils ) Dielectric Constant (ER1) Trace Information . Trace width. JLCPCB Impedance Calculator. There are four different types of impedance used in characterizing differential trace impedances. For example, if you wish to input "25000000. 6mm thick. Voltage regulator circuit board. Color Code. TanD 0,015. 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. Sierra Circuits’ Via Impedance Calculator uses the physical dimensions of a via to calculate its capacitance, inductance, and impedance. Trace Current Calci User Inputs: [Amps] [Degrees C] [oz. net Forum. 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). 4-Layer Impedance Control Stackup. H 2 H 2 = subtrate height 2. Pad Stack Calculator 4. comments closed; Find PCB Trace Width Based on Power April 20, 2006. PCB Trace Width Calculator This 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. The Calculator has the following tools:.