Uniform Resister-Capacitor Transmission line (URC)

The URC transmission line is useful for  modeling semiconductor resisters that have distributed capacitance, or  semiconductor capacitors with series resistance  to a tank/well/substrate.

The setup dialog specifies resistance and number of sections to model the RC line with

netlist syntax is:

u1 node1 node2 node3 model_name L=[value] N=[value]

.MODEL ResisterInTankURC_XN urc(rperl=1K cperl=100u)

The GUI dialog allows direct setting of length and the number of sections.

Note:

Current probing of the URC pins is not support at this time. Probed current values will be erroneous, however the model will simulate correctly.

Spice3Manual Description

The URC model is derived from a model proposed by L. Gertzberrg in 1974. The model is accomplished by a subcircuit type expansion of the URC line into a network of lumped RC segments with internally generated nodes. The RC segments are in a geometric progression, increasing toward the middle of the URC line, with K as a proportionality constant. The number of lumped segments used, if not specified for the URC line device, is determined by the following formula:

                                             2
                     |     R C        |(K-1)|  |
                           _ _      2
                  log|F        2 J L  |-----|  |
                       max
                     |     L L        |  K  |  |

             N =  ------------------------------
                              log K

The URC line is made up strictly of resistor and capacitor segments unless the ISPERL parameter is given a non-zero value, in which case the capacitors are replaced with reverse biased diodes with a zero-bias junction capacitance equivalent to the capacitance replaced, and with a saturation current of ISPERL amps per meter of transmission line and an optional series resistance equivalent to RSPERL ohms per meter.

     name     parameter                            units   default   example   area

  1   K        Propagation Constant                 -       2.0       1.2       -
  2   FMAX     Maximum Frequency of interest        Hz      1.0G      6.5Meg    -
  3   RPERL    Resistance per unit length           Z/m     1000      10        -
  4   CPERL    Capacitance per unit length          F/m     1.0e-15   1pF       -
  5   ISPERL   Saturation Current per unit length   A/m     0         -         -
  6   RSPERL   Diode Resistance per unit length     Z/m     0         -         -

See also Resistor Labels

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