IPC 6012 CLASS 2. 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. Microstrip Transmission Line Models. 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. F-A t t enua t o rs. 4 mil, εr. Once the required impedance and trace geometry are determined, the next step is to calculate the trace width. 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. 0. The shortcomings of crosshatch or mesh as a high frequency return path. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. Matching the differential trace length and keeping the distances between the traces consistent is a common practice. The aim of the Impedance Calculator is to support the. PCB Trace Width Calculator. ( 0. For more accurate numbers, you can use a trace impedance calculator online. 5 mm, trace width W = 0. Trace width. The other option is to use a calculator based on either IPC-2152 or IPC-2221 standards. And this is enough to initiate low-level oscillations. Neither of those cover controlled impedance calculations, if you need those look elsewhere. The tool achieves this by applying particular formulas for each component, conforming to industry standards such as the IPC-2221 standard for circuit board design. Coplanar Waveguide Calculator. 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). In the case where there is a plane present, a correction factor is applied to determine the required copper. With PCBWay impedance calculator, you can calculate the approximate impedance of your PCB / high frequency circuit board. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. The inductance of a broadside coupled trace is easy to calculate. comments closed; Find PCB Trace Width Based on Power April 20, 2006. Aside from impedance and annular ring calculations, one of the other major formulas specified in this standard relates temperature rise, trace width, and trace current. By plotting the above equation for common temperature values, we can obtain the following chart. Impedance calculators or formulas like the one mentioned earlier can help determine the required trace width. Equation 3. Published by John Coonrod, Technical Marketing Manager on Oct 13, 2020. This should be provided along with the PCB material. Instructions. 393 mm, the required trace width for this particular inductance value is w = 0. Track width, in this specific case where impedance control is not needed, must guarantee a smaller enough resistance to the trace. The default units for all given values, except the substrate dielectric, is in mil. 6mm2. A 3D view of a complex impedance controlled PCB in Altium Designer. Figure 2. This calculator is designed to calculate the characteristic impedance of a broadside couple stripline (see diagram below). . 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. INPUT DATA. PCB Trace Impedance Calculator. Using the built-in Simbeor ® impedance calculator, the PCB editor's Layer Stack Manager calculates the trace width needed to deliver the specified impedance. If you know the values of any of the two parameters (conductor width, max temperature, max current capacity) it determines. The Dk of a PCB material largely determines the trace width of controlled impedance transmission lines on the circuit board; the greater the Dk value, the lesser the trace width will be for the same target controlled impedance value. 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. Calculates the characteristic impedance and per-unit-length parameters. 1. Color Code. But it can calculate the wave impedance of a trace that feeds an antenna structure. IPC 2141 Trace Impedance Calculator. For my results, I find that the minimum inductance is 292 nH per meter when ( w/h) = 1. The application below provides a simple way to calculate the required trace width (in mil) for a given input current and temperature. This calculator determines the impedance of a symmetric differential stripline pair. 4mil and the dielectric thickness to the first intermediate layer (this is a 4-layer board) is 6. There are four different types of impedance used in characterizing differential trace impedances. 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. This calculator requires symmetry in the trace widths and location between plane layers. β1 = 0. 2mm from the ground plane below. To learn more about trace impedance calculators, Wadell’s equations, and some drawbacks of impedance calculators, read this article on single-ended microstrip impedance calculators. What is Microstrip Impedance? As you adjust the width of the line, you can eventually get the microstrip impedance calculator to converge on the desired impedance value, and you have finished designing the microstrip trace. ( 0. 1. Factors Affecting Coplanar Waveguide Impedance When calculating coplanar waveguide impedance, there are many factors that affect the waveguide’s impedance, losses, and isolation:This calculator is designed to calculate the characteristic impedance of a symmetric stripline - a flat conductor between two ground planes whose distance between the conductor and the planes is the same for both reference planes. Radar Calculators. Thickness. Inform the manufacturer about the number of layers, the value of impedance traces, and PCB material. 92. The dialog is accessed from the PCB Editor by clicking the Impedance Calculation button in the Layer Stack Manager dialog. Now also calculates DC resistance with temperature compensation. The characteristic impedance of the trace can be calculated using the below formula: Formula to calculate characteristic impedance of a PCB trace. For example, let us input 30°C ambient temperature, 1oz via plating, and 0. Let's consider the impedance for copper at 1 MHz. And the equivalent current carrying capacity equation will be: For outside visible traces the coefficient values are: K = 0. The default units for all given values, except the subtrate. Tools Landing. Board Classes. View All Tools. The new IPC-2152 standard is a significant improvement over the previous IPC-2221 standard. When designing differential pairs and determining their impedance, it’s important to understand how coupling will affect the pair. Effective Antenna Aperture Calculator. The impedance depends on the net width, the net height, the board type and so one. At the point of bending, the trace width is 1. 41)] * ln[5. Impedance trace widths based on Bittele's standard Stackups One of the most common inquiries that we encounter at Bittele electronics are regarding our standard trace widths. 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. Share. If the ratio is about 0. W=trace width. Microstrip Impedance Calculator. Coil Inductance Calculator. The dielectric constant of a material IS slightly frequency dependent. 0. of typical printed circuit board trace geometries. 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. It's open-source to download. Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. Here, the via carrying the signal is placed at the center and is surrounded by 4 ground vias. Thermal. 2-side PCB, one side with signals, the other with GND. 378 [mils/oz/ft. Also, the copper thickness affects the minimum trace. 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. Pick a signal frequency for your taper. It is now a major exercise to evaluate the impedance using a calculator or spreadsheet. PCB Trace Impedance Calculations. The impedance calculator will then use this information along with the target impedance values to make its trace width calculations. Figure- Allegro automatically assigns trace width 12. 17mil is the PP thickness between impedance trace layer and reference layer,it is 0. Sorted by: 8. The Calculator. Home;. It is not uncommon that the calculated trace width will be a value that cannot be ordered, for. 98H / (. Dual Stripline. Best is 5mils, but 4mils is OK, too. W: trace width: T: trace thickness: H (/H1)The trace width calculator uses empirical formulas based on long traces with no special heat sinking. To reach 90Ohms, there are 2 ways (or there is another, please advise!): 1. **Note: Like our stripline impedance calculator, all of our RF calculators allow SI prefix input. 7E-6 [Ω · cm], L is the trace length [cm], α is the resistivity temperature coefficient, whose value for copper is 3. Hi all, I'm trying to route some 90? differential pairs for some USB 2. This form of microstrip is composed of two traces. When working with a power rail, high-voltage components, and other portions of your board that are sensitive to heat, you can determine the power trace width you need to use in your layout with a PCB trace width vs. t t is the trace thickness, in oz/ft 2. 2mm0. 024 x dT0. Impedance control: Here, the impedance is controlled through the dielectric thickness, the trace width, and space. Differential Impedance Ω. You can’t rely on these online calculators. Try This New Tool. Overview. This is. There are four different types of impedance used in characterizing differential trace impedances. The Smith Chart achieves this by superimposing a grid on S11 that maps load impedance. For a first design (e. There are some advantages to using a. For example, on the left side of Figure 4, a 4-4-4 mil geometry has a differential impedance of 91 Ohms. In HDI boards, where BGAs of fine pitch are used, careful selection of trace widths and height are employed to escape the traces between pads and vias in pads. Simons, "Coplanar Waveguide Circuits, Components, and Systems", Wiley. It is possible to select other units. Microstrip. Simpler calculators will use the less-accurate IPC-2141 equations. Our current online trace width calculator is useful for clients who need to calculate the minimum/maximum trace widths for. Note that vias are made out of plated copper which typically has a resistivity of 1. Use our online tool to calculate the minimum trace width for a given current and copper weight. Menu. The board thicknesses are given in mm so it is not clear that the required units for trace width appear to be mil (0. Select the trace under properties. ) such real numbers for the line impedances are sufficient. Dielectric Height (H1) ( mils ) Dielectric Constant (ER1) Trace Information . 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. Adequate trace width is necessary to ensure the desired amount of current can be transported without overheating and damaging your board. These calculators will return an impedance value for pairs of trace width, substrate thickness, and copper weight values. Cite. Trace Thickness (T) 2. One commonly used formula for calculating the characteristic impedance of a PCB trace or transmission line is the capacitance per unit length formula: Z0 = 1 / (C / L) where Z0 is the. εr:Controlled impedance traces can minimize signal reflections and thereby reduce propagation delay. For a 0. Dielectric material: This is the prepreg and core materials utilized on each side of the controlled impedance trace layer. as input parameters i looked up the material datasheet from my board house and got: Er 4. All of the transmission lines are 1 ounce (1. 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. This flow is outlined below. 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. 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. Can PCB traces be too wide? Yes, PCB traces can be too wide, which may lead to inefficient use of board space and increased manufacturing costs. I made the calculator as an Excel Spreadsheet and posted it on Zoho Sheet. Input your data. Follow edited Oct 20, 2010 at 20:24. To use it, first select the tolerance of the resistor: 10%, 5% or equal or smaller than 2%. In the first section of the PCB DFM tool, you need to key in the part number (name of the design), revision (edition of the design), number of layers on the board and board dimensions. 0mmCurrent layer:4-layer. 25mm trace. 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. Impedance control with BGA escape. Impedance (Z) = [87 / √ (ε + 1. trace width:. 5mil0. Includes information on how trace width is calculated. Place critical components, such as microcontrollers or high-speed ICs, close to the power source to avoid trace stubs. Deliver -/+ 5% impedance tolerance. of typical printed circuit board trace geometries. For the antenna conection I should calculate the width to fit 50 ohm right? I tried to calculate the impedance, but I am getting a large width for antenna track (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. Other parameters to consider. The trace width can then be adjusted. 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. 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 values for trace thickness, substrate height, trace width. Abrupt changes in trace width cause impedance discontinuities. Since my layer thickness is 0. To use these to design for a target impedance, simply cycle through various geometric. Inputs: Optional Inputs: Results for Internal Layers: Results for External Layers in Air: Notes: The trace width is calculated as follows: First, the Area is calculated: See full list on protoexpress. Trace width is one of the most influential elements affecting characteristic impedance and Figure 4 below demonstrates the relationship between characteristic impedance and trace width. Where: Z0 Z 0 = characteristic impedance of the asymmetric stripline in ohms (Ω). To find what a given trace width will have a single ended or differential impedance, we can use a built in calculator from Allegro. FYI, I followed 2nd option and values were quite similar. 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). The wider a trace is, the easier it is to fabricate. Obviously, there is no ground on the bottom side. 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. 533 to target 50 Ohms impedance. Pad Stack Calculator 4. Having carefully specified the board/prepreg material, I also ask for tolerances and based on that calculate the widths for eg. Trace-Width Calculator (PCB Trace Power Handling Calc) Calculates trace width values based on using the IPC-2221 (A) equations. Calculate the effective dielectric constant. The Smith Chart graphically maps S11=reflection coefficient= (ZL-Z0)/ (ZL+Z0) to Load Impedance (ZL), normalized to Z0 (source impedance = center of chart). Altium Designer includes a PCB trace impedance calculator, PCB trace width calculator under IPC 2152, and a plethora of other important design tools. Just enter the given values for trace thickness, substrate heights, trace width, and substrate dielectric in the. I would like to calculate the trace width of a dipole PCB antenna in order to match a 50ohm impedance. per sq. Qorvo Calculators and Design Tools MatchCalc Qorvo MatchCalc is a free downloadable RF/microwave matching calculator with ideal tunable passive components. Looking at the design I should have done the following but do not think them alone would explain the results. Uncoated microstrip single-ended impedance calculator. 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. Trace impedance is dependent on not only. However, at this time, I don’t know of a good way to do calculations for wagon wheel spokes. A higher Dk value also leads to higher dielectric loss. 08mm, my trace width should be 0. A PCB. 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. 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. At the point of bending, the trace width is 1. 4 mm, trace spacing S = 0. 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. 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. You can reduce this effect by implementing coaxial via structure. They are:. 5. Features: Three-in-one calculator. Height: Height of the substrate. Step 4. RF IC -> Balun N/W -> PCB antenna or Chip Antenna. Trace impedance is detrimental to high-frequency signals, especially when the. 9E-3 [1/°C], T TEMP is the trace temperature [°C]. 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. For two layer boards, a coplanar waveguide geometry usually gives more useful dimensions than a microstrip geometry. 254mm, spacing between both is required 0. they normally use 7. 4 ohms; differential impedance: 90. This is more than the to times trace width which is recommended (also read as close as possibly). This calculator assumes the distance between the two reference planes to be an equal distance. 1. Impedance Calculator; Via Impedance Calculator; Trace Width and Current Capacity Calculator; Via Current Capacity Calculator; Signal & Plane Layer Estimator; Conductor. 5oz. Trace width is an important design parameter in PCB design. Single Ended Impedance Ω. 30967mm) is slightly larger the size of the smallest pad (0. 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. Microstrip Width Calculator. There are several parameters to consider when determining impedance, including:. 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. 0mm1. Keep in mind that the reactance of the ideal inductor has the same magnitude as its impedance. Trace impedance is dependent on not only. Hi there, and welcome to the Tools portion of EEWeb. 6mm spacing with a trace width of 0. Vias (plated holes) are used to route electrical signals among different layers of a multilayer. Microstrip Impedance Calculator. The trace geometry and material affect the controlled impedance of the trace. Using. After determining the layer thickness and copper weight, you simply determine the trace width you need to use for a defined characteristic impedance. Differential Impedance Ω. Calculating the Impedance. 1 mm. Via Current Calci 1. 25mm between the differential pair with a width of 0. $$H$$ = subtrate height $$W$$ = trace width $$T$$ = trace thickness $$epsilon_{r}$$ = substrate. It displays the impedance of the input and output match in a 50-ohm test environment as measured on a network analyzer. 78 mils; with the lower trace width etch factor at 1 mil the lower trace width will therefore be 6. so i opend the KiCad PCB Calculator and tried to get some values out of this. Step 3: Calculate the Trace Width. 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. 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. Stripline Impedance. Here, =. *As Trace Width Increases, Trace Impedance Decreases (Thickness has Min Effect). There are several formulas and online calculators that can be used to calculate trace width. Sierra Circuits follow this. Also for differential LVDS signals the tool can calculate the trace width and spacing for 100 ohm impedance for a given stack up setting. Trace Current Calci User Inputs: [Amps] [Degrees C] [oz. I would like to increase the width of my traces whilst maintaining the same ~50 Ohm nominal characteristic impedance of my line. Just as a sanity check, we can quickly calculate the total inductance of a trace. ] Internal Layer Results: Copper Area: External Layer Results: [Mils] [Square Mils] [Volts] Trace Width Calculator Results: Via Current. Simply enter your required temperature rise limits and operating current (RMS). An embedded microstrip can be constructed using a microstrip with a solder mask. This calculator can calculate the impedance and propagation delay of the embedded microstrip. 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. A higher current requires thicker traces while a thicker. 25 Dimensional units: mm milsA uniform transmission line on a PCB has a definite trace width and height, and is at a uniform distance from the return path conductor - which is usually a plane at a certain distance from the. This is assuming that you have a Design Rule in place which links the impedance profile to a. For example, if you wish to input "25000000", just type "25M" instead. 25 mils , t = 1. Electromagnetic fields are part of the spectrum ranging from static magnetic fields to high-intensity gamma rays. Stripline Trace. 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. 98H / (. The trace width and spacing for a certain impedance may be obtained using impedance calculator s. It includes calculations for trace width, impedance, current-carrying. For a standard FR-4 substrate with a dielectric constant of around 4. 946 for silver, or 1. 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. 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. However, minimum trace width recommendations from manufacturers should be. This will work with the controlled dielectric approach, where you specify the stackup, and then you adjust the width and dielectric constant to hit a trace width and impedance target. H: Height (thickness) of the dielectric substrate. 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. Impedance trace widths based on Bittele's standard Stackups. trace width for a characteristic impedance of 50 Ohms on Dk = 4. This can be calculated in function of current, here you can set up for your specifications Trace width calculator. The Track Width tool calculates the trace width for printed circuit board conductors for a given current and temperature rise. Note: Units do not matter for this calculation as long as they are consistent. 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. Identify best matched Rogers' bonding material by sorting according to design attributes. These are precisely the characteristics of a pair of lines to be designated as a differential pair. The characteristic impedance of your microstrips is determined by the trace width for a given layer stackup. T T = trace thickness. But if you route a pair of traces with close coupling, the odd-mode impedance is less than the SE impedance for the same trace width (unless you adjust the line width). For example, when a trace bends at an angle of 90 degrees, trace width changes significantly. t. Access. With the RF Attenuator utility you can calculate the values of the resistors needed for different types ofColor-Code. e. 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. 08 mm: 3. ϵr ϵ r = substrate dielectric. via stitching to GND plane. 7 ohms; common impedance: 19. To use this tool, enter the trace width, thickness, ambient temperature, temperature rise, and the microstrip length and click the "calculate" button. These calculators mostly ignore the losses. spacing: 0,15mm. The width of each track should be as per the requirements. I'm not sure which calculator to trust. 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. It is important to note that in industry we can find that some differential pairs are routed this way for a strong coupling, but. 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. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. To use it, first select the tolerance of the resistor: 10%, 5% or equal or smaller than 2%. Before, working with a trace impedance calculator, one should be aware of which equations the calculation uses. This page covers Microstrip Width Calculator. It’s a three-in-one. Stripline. Just enter the given values for trace thickness, substrate heights, trace width and substrate dielectric in the calculator above and press the "calculate" button. Via is considered as a cylinder of copper and its circumference is 2 𝝅r or 𝝅d where d is the size of via hole. Cite. To find out the width of the microstrip, enter the target impedance (Zo), trace thickness (t), dielectric thickness (h), and relative dielectric constant (εr). Microstrip Trace Impedance vs. Select a configuration: Microstrip Trace. Online calculators will generally use Wadell's equations to determine the transmission line impedance numerically. Balun's Single Ended Impedance = 50 Ω Ω. Once the routing is done check the trace width. Odd Mode Impedance (Zodd) Ω . MICROSTRIP WIDTH CALCULATOR. Next, determine the trace height/length. where Z 0,surf can be computed as specified in Eq. Next, determine the trace. The designer can normally enter their desired impedance, and the calculator will determine the PCB trace width needed to meet that impedance goal. Scientific Calculator. This procedure produces the result ( w/h) = 1. It supports both balanced and unbalanced lines. Microstrip Mitred Bend Calculator. 8 * W + T)]) ohms. Learn More about using the Altium Designer’s impedance calculator in this brief tutorial. You can also calculate the accurate drill diameter, via to via spacing, and the thermal vias that. Saturn PCB Toolkit is the best tool for PCB Designer to calculate trace width, via current calculation, Thermal dissipation, etc. H (Dielectric thickness) :This means that the actual trace width for a 50 ohm line could vary from design to design. 7E-6 to 2. You can calculate maximum current by using the formula A = (T x W x 1. This is the reason why engineers specify the trace width in their designs. 679 nH. Enter 9. Using a calculator with an existing stackup involves a simple process to converge on a useful trace width for a target impedance. The circumference will be analogous to the trace. 18. Calculations are based on formulae from IPC-2221.