Appendix F

Files on the Web

In this last appendix the reader can find a list of files available on the web concerning computations by MathCad (file.MCD) or simulations by MicroCap9 (file.CIR) reported in the book.

F.1 Program Files of Chapter 1

• CMOS_TL_DIODE_L_CMOS.cir. The model computes reflected waveforms in an interconnect point-to-point structure where driver and receiver are a CMOS gate formed by three MOS inverters. It is shown, with the option stepping of parameter pL, how the signals change according to the presence of the parasitic inductances. Since macros are used for X1 and X2 models, check the path of the required file on your computer. For more details, see Section 1.3 of the textbook, where the other examples can be easily reproduced with this model. Run transient analysis.

F.2 Program Files of Chapter 2

• AC244_TR_5pin_TL_cir. The program calculates the waveforms in a point-to-point interconnect structure by using the IBIS model of the CMOS device AC244. The user can choose a min, typ, and max characteristic of the driver and receiver. For more details concerning the I/O characteristics of AC244, see Section 2.4. Run transient analysis. Check the path of the IBIS model on your computer.

F.3 Program Files of Chapter 5

• TERMINATION_LH.cir. The program computes the reflections in a point-to-point interconnect owing to low-to-high switching by using the exact lossless line model outlined in Section 5.2. Driver and receiver are represented by Thévenin equivalent circuits. The computed waveforms in several termination conditions (unmatched, series, Thévenin, parallel RC) can be compared with those shown in Figure 5.27.
• TERMINATION_HL.cir. The program computes the reflections in a point-to-point inter-connect owing to high-to-low switching by using the exact lossless line model outlined in Section 5.2. Driver and receiver are represented by Thévenin equivalent circuits. The computed waveforms in several termination conditions (unmatched, series, Thévenin, parallel RC) are obtained.
• Lossless_line_term_LH.mcd. The program computes the reflections in a point-to-point inter-connect by using the exact lossless line model outlined in Section 5.2. Driver and receiver are represented by Thévenin equivalent circuits. The computed waveforms in several termination conditions (unmatched, series, Thévenin, parallel) can be compared with those obtained by SPICE and shown in Figure 5.27.
• Lossless_line_term_HL.mcd. The program computes the reflections in a point-to-point inter-connect by using the exact lossless line model outlined in Section 5.2. Driver and receiver are represented by Thévenin equivalent circuits. The computed waveforms in several termination conditions (unmatched, series, Thévenin, parallel) are derived.

F.4 Program Files of Chapter 6

• Even&odd mode model.cir. The program computes the signal and crosstalk waveforms of two coupled lines by using the exact model based on even and odd modes outlined in Section 6.2.
• F00_BOOK_IN_OUT_DC.cir. The program computes the I/O static characteristics of the F00 device used in the simulation of two and five coupled lines presented in Chapter 6. For more details concerning the model parameters, see Section 6.3. Run DC analysis.
• AC00_BOOK_IN_OUT_DC.cir. The program computes the I/O static characteristics of the AC00 device used in the simulation of five coupled lines presented in Section 6.4. For more details concerning the model parameters, see Section 6.4. Run DC analysis.
• Distributed5L_F00_mac.cir. The program computes the signal and crosstalk waveforms of five coupled lines with F00 digital devices. Details about the device and the coupled-line models with experimental validations can be found in Section 6.4. Run transient analysis. As macros are used, check the correct path on your computer.
• Distributed5L_AC00_package_mac.cir. The program computes the signal and crosstalk waveforms of five coupled lines with AC00 digital devices. Details about the device and the coupled-line models with experimental validations can be found in Section 6.4. Run transient analysis. Since macros are used, check the correct path on your computer.
• LC_Xtalk_F00_AC00_5lines.mcd. The program computes the parameters required by the coupled-line model outline in Section 6.4 starting from the per-unit-line matrices of capacitance and inductance. The output of the program is the input for the file: Distributed5L.mac in the directory “component-library” of MicroCap.

F.5 Program Files of Chapter 7

• S_LOSSYTL_ANALYTICAL_10GHz.CIR. The program computes S₁₁ and S₂₁ parameters of a coaxial cable by using closed-form expressions for the per-unit-length line impedance and admittance. The VNA has an output and input impedance of 50Ω. The coaxial cable has a characteristic impedance Z₀ = 49.94Ω. The line is modeled by Laplace sources. The same circuit can be used for any DUT expressed by an equivalent circuit. For more details, see Section 7.2 and Section 11.2. Run AC analysis.
• S11_S12_trace.mcd. The program computes the voltages at source and load when the lossy interconnect (a trace in this case) is matched at both ends. The computation is performed in the frequency domain, and the voltages in the time domain are obtained by IFFT. The waveforms obtained can be used as input for the SPICE model, based on the S-parameters outlined in Section 7.2. With a simple modification, the program can compute voltages with different sources and loads.
• Alpha_stripline_Kp.mcd. The program computes the characteristic impedance and attenuation of a symmetric (h = b/2) stripline, considering both skin and proximity effects, and dielectric losses. The coefficient K_p for proximity-effect prediction is computed as the ratio between the attenuation with both skin and proximity effects and the attenuation with the skin effect only. For more details, see Section 7.1 and Appendix B.
• Alpha_microstrip_Kp.mcd. The program computes the characteristic impedance and attenuation of a microstrip, considering both skin with proximity effects, and dielectric losses. The coefficient K_p for proximity-effect prediction is computed as the ratio between the attenuation with both skin and proximity effects and the attenuation with the skin effect only. For more details, see Section 7.1 and Appendix B.
• Twisted75m_eye.mcd. This program, written in MathCad language, computes the response of a 75 m twisted-pair cable when the line is sourced by a NRZ sequence of bits. The lossy-line model outlined in Section 7.2, based on convolution integrals, is used. The required inputs are the S-parameters of the cable in the time domain, measured or computed, and the NRZ sequence for the voltage source. The outputs are the voltages at source and load, obtained by lossless and lossy-line models and the eye diagram on the load. The reader can learn how to implement:
  • the lossy-line model based on S-parameters in the time domain;
  • the convolution integral to solve the lossy line;
  • the expression to obtain the eye diagram.

  Remark: the computation with the line models must be performed on the variation in the voltages and currents in line and not on the total values: DC plus variations.

F.6 Program Files of Chapter 8

• CMOS.cir. This circuit implements three MOS inverters in series. It is used in file ‘CMOS_2_TL_3chip_mac.cir’ for bounce investigation, and in file ‘CMOS_TL_DIODE_L_CMOS.cir’ of Chapter 1 for reflection investigation. View transient and DC analysis for the appropriate simulations.
• CMOS_IN_OUT_DC_3gates.cir. The model computes the DC I/O characteristics of a CMOS inverter used in file ‘CMOS_2_TL_3chip_mac.cir’ for bounce investigation. Run DC analysis.
• CMOS_2_TL_3chip_mac.cir. The program simulates the ground and power bounce of a CMOS IC as a result of the inductances associated with the lead and package conductors of the IC. Two gates switch simultaneously, and a third gate is set quiet at low- and high-output level by using the stepping option. For more details, see Section 8.3.2. Run transient analysis. Since macros are used for the gates, check the correct path of the required file for X1, X2, X3 models on your computer.
• Power_Bus_port_matrix.mcd. This program computes the impedance Z₁₁ at port 1 between two parallel rectangular planes separated by a dielectric support of thickness w_z, the transfer impedance Z₁₂ between ports 1 and 2, or Z₁₃ between ports 1 and 3 by using the cavity model outlined in Appendix C. The excitation is a current source of 1 A amplitude located at port 1. The computation can be performed with the bare board or with three distributed decoupling capacitors. The extension of the program to more capacitors is straightforward.

F.7 Program Files of Chapter 9

• TRAP.mcd. The program computes the spectrum of a trapezoidal waveform representing a clock signal. Three expressions are compared: envelope, analytical, and harmonic representation. For more information, see Section 9.1.
• D_INOISE.mcd. The program computes the spectrum of three waveforms with period T_p representing impulsive noises in aPCB: triangular, Gaussian, and damped oscillation. The signal parameters are defined in Section 9.1.3.
• EMISCM.mcd. The program computes the common-mode current and the consequent radiated field in the far field of a PCB formed by two parallel wires, driven by a digital signal, and terminated on a resistive load. The PCB is isolated and has as reference plane the metallic floor of an open field site. The equivalent circuit of the dipole consists of lumped elements such as the inductance associated with the wires, the capacitance between wires, and the radiation resistance. The dipole is fed by half the voltage source of the interconnect, considering that the common-mode current is generated by the asymmetric position of the source with respect to the line. For more details, see Section 9.2.
• EMISDM.mcd. This program computes the differential-mode current and the consequent radiated field in the far field of a PCB formed by a wire above a ground plane, driven by a digital signal, and terminated on a resistive load. The PCB is isolated and has as reference plane the metallic floor of an open field site. Applying image theory, the equivalent circuit of the PBC is a line of two parallel wires spaced at twice the height of the wire from the plane, driven by a doubled voltage source, and terminated with a doubled load. This program can also be used for a microstrip-line structure once the characteristic and propagation delay are known and extended to more complex sources and loads. For more details, see Section 9.2.
• COUTRACK_2wires.mcd. The program calculates the radiated field in the far-field zone, generated by a cable attached to a PCB and outgoing from a shielded rack. The PCB consists of two parallel wires driven by a digital signal. The common-mode current responsible for the radiation is produced by the voltage drop on the return wire as the product of the differential-mode current of the circuit and the associated partial inductance L_gnd of the return wire. It is assumed that the rack is the reference plane for the vertical path of the cable and the metal floor of the open site is the reference plane for the horizontal path of the cable. For both polarizations, image theory is applied. The phase difference between the direct and image field is accounted for along the distance from the coordinate origin and the observation point. The model is valid up to the frequency where the distance of the cable from the reference plane is electrically short, in this example about 300 MHz. For more details concerning the source of the circuit and the circuit itself, see ‘EMISCM.mcd’ and Section 9.6.
• COUTRACK_1wire_1plane.mcd. The program calculates the radiated field in the far field, generated by a cable attached to a PCB and outgoing from a shielded rack. The PCB consists of a wire above a ground plane driven by a digital signal. The common-mode current responsible for the radiation is produced by the voltage drop on the return plane as the product of the differential-mode current of the circuit and the associated partial inductance L_gnd of the return plane. It is assumed that the rack is the reference plane for the vertical path of the cable and the metal floor of the open site is the reference plane for the horizontal path of the cable. For both polarizations, image theory is applied. The phase difference between the direct and image field is accounted for along the distance from the coordinate origin and the observation point. The model is valid up to the frequency where the distance of the cable from the reference plane is electrically short, in this example about 300 MHz. For more details concerning the source of the circuit and the circuit itself, see ‘EMISDM.mcd’ and Section 9.6.
• EMSHCM.mcd. The program computes the radiated field in the far field of a PCB formed by two parallel wires within a shielded box with a rectangular aperture. The low-frequency model of an aperture, described in Section 9.8.4, is used. For details about the PCB and set-up, see the file EMISCM.MCD.
• EMISHDM.mcd. The program computes the radiated field in the far field of a PCB formed by a wire above a ground plane within a shielded box with a rectangular aperture. The low-frequency model of an aperture, described in Section 9.8.4, is used. For details about the PCB and set-up, see the file EMISDM.mcd.

F.8 Program Files of Chapter 10

• DEFZT_V_K_full.cir. The program computes the disturbance on the load R_L produced by a voltage source V_i for two return-wire diameter values: 1 mm and 10 mm. Two equivalent circuits are used: one based on mutual inductance and the other based on the transfer impedance concept. It is shown that the two equivalent circuits provide the same results. For more details, see Section 10.1.2. Run AC analysis.
• wrplane.mcd. The program computes the current density in a finite ground plane produced by an impressed current I_z of frequency f flowing in a wire above the plane. The structure has infinite dimension along the z axis. The method of moment, as outlined in Section 10.2, is used. The radiated E-field is also computed at a distance r = 3 m, and the consequent radiation pattern is compared with that obtained by using an equivalent short dipole of length l.
• stripsim.mcd. The program computes the current density in the two ground planes of a stripline structure produced by an impressed current I_z of frequency f flowing in a wire placed between the two planes. The structure has infinite dimension along the z axis. The method of moment, as outlined in Section 10.2, is used. The radiated E-field is also computed at a distance r = 3 m.
• trace_plane_circ_MC.mcd. The program computes the current density in the plane of a microstrip structure by using the concept of partial inductance. The plane is divided into NM_y filaments. The nodal method outlined in Appendix E is used.
• trace_plane_plane_circ_MC.mcd. The program computes the current density in the two planes of a stripline structure by using the concept of partial inductance. Each plane is divided into NM_y filaments. The nodal method outlined in Appendix E is used.