eldo_user

IBIS Models Support in Eldo
IBIS Component
• eldova=ON|OFF
For external models and external circuits written in Verilog-A. Eldo will use its Verilog-A
compiler to handle these models if eldova=ON. Setting eldova=OFF enables these models
to be simulated with Questa ADMS. The default is ON.
• em_libname="logical_lib_name"
Can be used for external models and external circuits written in any AMS language. The
specified logical_lib_name library is used as the work library. If no library is specified, the
default work library will be used, specified with the Questa ADMS vasetlib command or the
vasim -lib command.
• table_tune=value
Controls Eldo time step when the IBIS buffer is switching to obtain accurate output
waveforms. Table_tune accepts non-negative values. Default value is 8.
Setting a value of 1 forces Eldo to take into account all the switching waveform points, 2 to
take one point into account and skip the next, 3 skips two points, but takes into account the
third, and so on. Setting a value of 0 makes Eldo control the time step regardless of the
switching waveform.
Note
The actual time step will be the minimum among the time step of the current IBIS
buffer, time steps of other IBIS buffers, and the time step forced by Eldo.
HMIN is always set as the lower limit for the time step.
• logic_one=value|logic_zero=value
Define the voltage level accepted by IBIS buffers for digital ports, logic_one default is 1.0,
and logic_zero default is 0.0. logic_one must be greater than logic_zero by at least 200mV.
The input voltage is considered ‘logic 1’ if it is greater than (logic_one + logic_zero)/2, and
considered ‘logic 0’ if it is below this value.
Note
These levels are defined for native IBIS buffers and do not apply to external models.
• c_fixture=YES|NO
Enable/disable using rising or falling waveforms that have a c_fixture sub-parameter with a
non-zero value. Setting to NO makes Eldo discard these waveforms; YES (default) to use
these waveforms.
• keep_monotonic=YES|NO
Used to control Eldo behavior with non-monotonic data. Setting to YES Eldo fixes the nonmonotonic
data provided in the tables, setting to NO (default) Eldo keeps the nonmonotonic
tables data as is. This keyword affects the data under [GND Clamp], [POWER
Clamp], [Pullup] and [Pulldown] IBIS keywords.
Eldo® User's Manual, 15.3 769