eldo_user

IBIS Models Support in Eldo
Buffers
If Vinl and Vinh are not specified in the IBIS file, the default values of Vinl = 0.8 V and
Vinh = 2.0 V are assumed for an Input buffer and Vinl = -1.475 V and Vinh = -1.165 V are
assumed for an Input_ECL buffer.
Terminator Buffers
A Terminator is an input-only model that can have analog loading effects on the circuit being
simulated, but has no digital output. The Terminator model is shown in Figure 17-2. It may
contain termination elements like Rgnd, Rpower, Rac, and Cac in addition to the usual clamping
diodes circuitry.
Figure 17-2. Terminator Buffer Model Building Blocks
Output and Output_ECL buffers
Figure 17-3 shows the model of an Output buffer (driver). It has four sets of I-V curves, a
ground clamp, a power clamp, a pull-up network and a pull-down network, and the die
capacitance C_comp. In addition, the transient switching characteristics of the pull-up and pulldown
networks are also defined.
736
Eldo® User's Manual, 15.3