Document 342-1 Transmission Line Model These transmission line models accurately simulate the frequency-dependent behavior of Coilcraft surface mount “Spring” air core inductors within the frequency limits shown in the accompanying table for each individual inductor. They are based on de-embedded measurements using a 2-port network analyzer. The model schematic, shown below, combines an ideal transmission line model with lumped elements. Each model should be analyzed only as a whole at the input and output ports. Conclusions based on individual lumped element values may be erroneous. The individual element values R1, R2, C, Z0, EL, and F0 are listed in the table for each individual spring inductor. C R1 Maxi Springs™ illustrated in Figure 1. The gap width for the Maxi Spring is 0.120 in. (3,048 mm). The test pads were 30 mil (50 Ohm) wide traces of tinned gold over 25 mil thick alumina, and were not included in the gap. The TRL* calibration plane is also illustrated in Figure 1. Pad Air gap Pad Brass ground plane Calibration plane Figure 1. Test Setup P1 50 Ohm TL1 Z0 EL F0 R2 P2 50 Ohm Effects due to different circuit board traces, board materials, ground planes or interactions with other components are not included. They will have a significant effect when comparing the simulation to measurements of the individual inductors using other production verification instruments and fixtures. Typically, the Self-Resonant Frequency (SRF) of the inductor model will be higher than a measurement of the component mounted on a circuit board. The parasitic reactive elements of a circuit board or fixture will effectively lower the circuit resonant frequency, especially for very small inductance values. Data sheet specifications are based on typical production measurements. These models are based on de-embedded 2-port measurements as described below, so the model results may be different from the data sheet specifications. Lumped Element Modeling Method The lumped element values were determined by matching the simulation model to an average of the measurements. This method results in a model that represents as closely as possible the typical frequency-dependent behavior of the component within the specified frequency limits of the model. The lumped element models were used to generate our 2-port S-parameters and therefore give identical results with the same number of simulation frequency points. The S-parameters are available on our web site at http://www.coilcraft.com/models.cfm. Disclaimer Coilcraft makes every attempt to provide accurate measurement data and software, representative of our components, in a usable format. Coilcraft, however, disclaims all warrants relating to the use of its data and software, whether expressed or implied, including without limitation any implied warranties of merchantability or fitness for a particular purpose. Coilcraft cannot and will not be liable for any special, incidental, consequential, indirect or similar damages occurring with the use of the data and/ or software. The measurements were made over a brass ground plane with each component centered over an air gap, as Specifications subject to change without notice. Document 342-1 Revised 05/28/03 Document 342-2 Transmission Line Model for Coilcraft Maxi Springs™ Part number 132-09SM 132-10SM 132-11SM 132-12SM 132-13SM 132-14SM 132-15SM 132-16SM 132-17SM 132-18SM 132-19SM 132-20SM Frequency limit of Model (MHz) Lower Upper 1 1 1 1 1 1 1 1 1 1 1 1 1500 1200 1200 1000 1000 1000 920 850 720 670 670 550 R1 (⏲ ⏲) R2 (⏲ ⏲) C (pF) Z0 (⏲ ⏲) TL1 EL (degrees) F0 (MHz) 1.921 2.221 1.963 2.341 8.285 10.000 9.601 9.309 8.766 8.411 10.56 13.05 0.2452 0.3273 0.3840 0.4527 0.5557 0.6117 0.6547 0.8173 1.000 1.091 1.276 1.476 0.1774 0.2105 0.2520 0.2103 0.1789 0.2089 0.2133 0.2071 0.1808 0.2221 0.1823 0.2130 307.5 336.5 363.2 443.0 515.7 511.0 516.5 579.4 650.3 645.7 756.7 722.8 76.06 77.28 82.64 86.95 94.73 91.76 79.87 77.34 78.17 87.64 93.23 88.90 725.2 654.7 646.3 638.5 664.5 592.9 471.6 411.7 378.2 381.0 408.1 341.4 Specifications subject to change without notice. Document 342-2 Revised 05/28/03