eldo_user

IBIS Models Support in Eldo
IBIS Buffers
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.
• add_series_terminator=YES|NO|IFA
Used with the pseudo/true differential buffers to enable/disable creation of series models
across the differential buffers die pads. Default is NO. IFA is the same as YES but does not
produce warning messages if there is no series models defined under [Series Pin Mapping]
for the differential buffers pins.
• 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.
• switch_isso=ON|OFF
Switch ON or OFF the effect of SSO (Simultaneous Switching Output) on the driver
current. The SSO effect is modeled in the IBIS file under the [ISSO PD] and [ISSO PU]
keywords. The default is ON.
• switch_composite_current=ON|OFF
Switch ON or OFF the effects of the power reference terminal current modeled by the
[Composite Current] keyword. The default is ON.
• check_model_spec=ON|OFF
Switch ON or OFF checking of the buffer input/output signals according to subparameters
given under the [Model Spec] keyword. The following subparameters are supported:
D_overshoot_area_h, D_overshoot_area_l, D_overshoot_ampl_h, and
D_overshoot_ampl_l. The default is ON.
Eldo® User's Manual, 15.3 759