12
Figure 7: Lumped RLCG including series inductance
OrCAD provides the following RLCG lumped models in the transmission line library:
Model Description Parameters
TLUMP1 1 RLC Lump R, L, C, G,LENGTH
TLUMP2 2 RLC Lumps R, L, C, G,LENGTH
TLUMP4 4 RLC Lumps R, L, C, G,LENGTH
TLUMP8 8 RLC Lumps R, L, C, G,LENGTH
TLUMP16 16 RLC Lumps R, L, C, G,LENGTH
TLUMP32 32 RLC Lumps R, L, C, G,LENGTH
TLUMP64 64 RLC Lumps R, L, C, G,LENGTH
TLUMP128 128 RLC Lumps R, L, C, G,LENGTH
Table 4. RLC Lumped models.
For example for TLUMP64, the value of R for one lump is R*LENGTH/64.
Transmission Line Couplings
Transmission lines may be coupled to study the effects of mutual inductive and capacitive coupling, such
as crosstalk. It is possible to use both a distributed and a lumped model for these macromodels.
Systems of coupled transmission lines can be described by their capacitance and inductance matrices.
The elements of the capacitance matrix C are defined by
Cij gives the charge induced on the ith conductor when conductor j is set to a potential of 1 Volt, and all
other conductors are grounded. The diagonal elements of C are related to the capacitance of the ith
conductor to ground by the following formula
j
i
ij
V
Q
C
