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2.2 GS3490 Cable Driver
In order to simulate the GS3490 model in cable driver mode, GS3490_CD_TX and
GS3490_CD_RX model files have to be used. The input termination impedance of the
GS3490 cable equalizer, which is provided as an S-parameter file, can be used in the
testbench to improve the simulation results accuracy.
simulation testbench for GS3490 cable driver model.
TX
Channel 1
Cable Driver Model
Figure 2-5: Block Diagram of a Sample Testbench to Simulate the GS3490 Cable Driver IBIS AMI Model
2.2.1 GS3490 Cable Driver Receiver Model
The GS3490 cable driver receiver IBIS-AMI model consists of three parts: (1) the Analog
Termination IBIS model, (2) the Receiver AMI model and (3) the QFN package model. The
block diagram in
Figure 2-6
of the model. The external S-parameter file for the QFN Package model extends the
accuracy of the package effects beyond which can be described by R, L and C
components in the current IBIS 5.0 standard. The external S-parameter data is processed
as part of the channel by the EDA platforms.
QFN Package
From Channel
(S-parameters)
Figure 2-6: GS3490 Cable Driver Receiver IBIS-AMI Model
The receiver IBIS model provides the characterized GS3490 cable driver receiver input
termination which is used by the EDA platform to determine the time-domain impulse
response for the channel. The model is based on a single-ended non-inverting
characterization of the GS3490 cable driver receiver and the EDA platform develops a
differential model from complimentary copies of the single-ended model. Note that the
IBIS model only contains the DC termination impedance of the receiver (I-V tables in IBIS
file) and doing frequency dependent simulations (e.g. return loss simulations) using the
IBIS file is not very accurate.
The GS3490 cable driver receiver AMI model only includes the slicer.
The GS3490 cable driver receiver QFN package model is provided as a 4-Port
S-parameter file (GS3490_DDI.s4p) in standard touchstone format from 0GHz to 15GHz
with 1501 data points.
GS3490
User Guide
Rev.0
PDS-060922
January 2015
CD_RX
CD_TX
SDO_Term.s2p
shows the sequence of signal flow and the individual parts
Analog
Term
www.semtech.com
Figure 2-5
shows a sample
Channel 2
AMI
IBIS-AMI Model
RX
5 of 7
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