Hello, I have updated BIRD 144 to support terminating: 1) unused ports, and 2) connected ports. The example below shows how. Figures and more details will be provided in the latest version of the BIRD , which will be uploaded very soon. |------------------------------------------------------------------- |** Example of True Differential [External Model] using Touchstone: |------------------------------------------------------------------- | | [Model] Ext_Linear_Diff_Output_Buff_Touchstone Model_type Output_diff Rref_diff = 100 | | Other model subparameters are optional | | typ min max [Voltage Range] 3.3 3.0 3.6 | [Ramp] dV/dt_r 1.57/0.36n 1.44/0.57n 1.73/0.28n dV/dt_f 1.57/0.35n 1.46/0.44n 1.68/0.28n | [External Model] ** Language Touchstone | | Corner corner_name file_name circuit_name Corner Typ diffout_typ.s4p NA Corner Min diffout_min.s4p NA Corner Max diffout_max.s4p NA | |** Ports List of port names (in same order as in Touchstone) | | Based on the Ports order below: |** my_drive_pos should be connected to port 1 of Touchstone |** A_signal_pos should be connected to port 2 of Touchstone |** my_drive_neg should be connected to port 3 of Touchstone |** A_signal_neg should be connected to port 4 of Touchstone | Ports my_drive_pos A_signal_pos my_drive_neg A_signal_neg |*** |**** Port_termination reserved_port ts_port resistor_value voltage_value **** Port_termination A_puref NA 1e6 0.0 **** Port_termination A_pcref NA 1e6 0.0 **** Port_termination A_pdref NA 1e6 0.0 **** Port_termination A_gcref NA 1e6 0.0 **** Port_termination my_drive_pos 1 50 NA **** Port_termination my_drive_neg 3 50 NA | | D_to_A d_port port1 port2 vlow vhigh trise tfall corner_name D_to_A D_drive_pos my_drive_pos A_pdref 0.0 3.3 0.5n 0.3n Typ D_to_A D_drive_pos my_drive_pos A_pdref 0.0 3.0 0.6n 0.3n Min D_to_A D_drive_pos my_drive_pos A_pdref 0.0 3.6 0.4n 0.3n Max D_to_A D_drive_neg my_drive_neg A_pdref 0.0 3.3 0.5n 0.3n Typ D_to_A D_drive_neg my_drive_neg A_pdref 0.0 3.0 0.6n 0.3n Min D_to_A D_drive_neg my_drive_neg A_pdref 0.0 3.6 0.4n 0.3n Max | [End External Model] Best regards, Feras Al-Hawari