BUS is a bundle of signals that have the same signal attributes.
DATA and ADDRESS lines are examples of BUS. In order to keep the same signal
attributes, they have the same length, width and via. In case of source synchronous
technology, send the clock (strobe) signal to be used to capture data with the data
signal.
This item checks the followings:
The delay time between bus nets.
The delay time between bus nets and strobe signal.
The timing skew between differential pair nets.
Figure 1.
Item: Sub item name. You can enter arbitrary name.
Check Type: Select a check type.
BUS Skew: Check the delay time difference between bus nets.
Strobed BUS Skew: Check the delay time difference between bus nets
and strobe signal.
Differential Skew: Check the delay time difference between
differential pair nets.
Strobe to Strobe Skew: Check the delay time difference between
strobe nets.
Net Group: Select target net groups to be tested. Allow multiple net
groups.
Strobe Group: Option to select target strobe net groups to be tested (Clock,
DQS, and so on).
Net Combination: Option to establish correlation between Strobe Net and
Dependent Net.
Start Component: Select component group to be used as signal driver.
Except Component: Select component group to be excluded. Allow multiple
component groups.
Analysis Mode:
Common mode: This is the part of the signal that appears equally on
both lines of a differential pair. Common mode can result from
external interference or imbalances and doesn’t contribute to the
intended data signal.
Differential mode: This is the actual difference in signal between
the two lines in a differential pair, which carries the intended
data.
Period(nS): Enter operating period in nS unit.
Skew(pS): Enter allowable maximum skew in pS unit.
Tolerance(%) option: Enter allowable tolerance of skew.
Analyze Options: You can assign driver/receiver buffer simulation model,
driving strength of driver and other simulation parameters.
There are two ways to assign the simulation buffer model:
Use pre-defined buffer model: The buffer model set in the electrical pin
part of UPE is used as default. You cannot change the buffer model
here.
Use user defined buffer model: You can assign simulation buffer model.
The default buffer model is initially assigned to the buffer model field which can be
changed.
Clicking Model field allows you to view the device models
selected for the output and input pins. You can change the device model selection
when multiple models are available for the pin.Figure 2.
Prior to running analysis, you can change the analysis control parameters such as the
number of random pulses and bit pattern style.
Model: The default buffer model is initially assigned to the buffer model
field which can be changed by users. For the selected active driver, actual
driver model can be selectable among many different models in IBIS or Linear
device model types. You can use one of available models considering the
output impedance, driving capability measured by output current level and
operating frequencies. These driver’s characteristics lead huge impact on
the simulated waveforms.
Simulation Type: You can select the simulation type also among Typical,
Fast, and Slow. The simulation type is applied to all device models used for
the analysis.
Dynamic ODT: This function allows for the individual configuration of On-Die
Termination (ODT) for each memory when multiple memories are connected to a
single controller on a PCB.
Number of random pulses for eye diagram: Means the number of random pulses
excited to the simulating net during the eye diagram analysis.
Preamble time: Simulation start after this time to wait until status of
internal circuit becomes stable.
Bit pattern style: Select the numerical method among random, ABS (Artificial
Bit Stream) and PRBS (Pseudo Random Bit Stream) for generating the bit
sequences. ABS (Artificial Bit Stream) is a method designed to provide a
large pattern of bits to show worst case signal transmission quality of the
net that would quickly converge the eye diagram. PRBS (Pseudo Random Bit
Stream) is the mostly common method deemed as an industry standard.
Bit pattern length: If bit pattern style is ABS or PRBS, choose the bit
pattern length here.
Default Device Models: When the device models are not available in the part
data, the default device models defined here are used for transient
simulation of signal integrity analyses. With the use of Linear Device
Modeler, users can create linear output (driver) and input (receiver) device
models and store them in a linear device model file. PollEx DFE+ provides
users with a system default linear device model file,
UDVS.dmf.
Include Package Skew: Measure the Skew by considering the Package Delay of
the parts. Package delay can be set through the Package Length Parameter tab
for each part in the Properties-Parts menu.