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GS3490
User Guide Rev.0
PDS-060922 January 2015
2 of 7
Propietary & Confidential
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1. Introduction
The GS3490 features integrated adaptive cable equalizer and cable driver functionality.
The GS3490 can be field-configured as a SMPTE compliant cable equalizer or a SMPTE
compliant cable driver. The GS3490's cable equalizer is optimized for operation at
2.97Gb/s, 1.485Gb/s and 270Mb/s while providing cable reach of 140m at 2.97Gb/s,
250m at 1.485Gb/s and 550m at 270Mb/s. In cable driver mode, the dual slew rate
capability provides compatibility to SMPTE ST 259, SMPTE ST 292 and SMPTE ST 424
interfaces. This document describes the contents, features, and use of the GS3490
IBIS-AMI model. The model includes the cable driver different swing settings, and cable
equalizer's different swing and de-emphasis settings and facilitates simulation of both
cable driver and cable equalizer in EDA platforms compliant with IBIS 5.0.
2. GS3490 IBIS-AMI Model
The GS3490 IBIS-AMI model includes both cable equalizer and cable driver models. Each
of these models consists of a receiver (RX) and a transmitter (TX) model. Therefore, the
GS3490 model consists of four models: two transmitters, and two receivers. In both
cable equalizer and cable driver modes, the RX model slices the signal received from a
channel and retransmits it into the second channel using the TX model. Figure 2-1
shows a general testbench to simulate IBIS-AMI models which can be used for the
GS3490 cable driver or GS3490 cable equalizer models. In the following sections, more
details about the model parameters and simulation testbenches are provided.
Figure 2-1: Block Diagram of a General Testbench to Simulate IBIS AMI Models
2.1 GS3490 Cable Equalizer
In order to simulate the GS3490 model in cable equalizer mode, GS3490_EQ_TX and
GS3490_EQ_RX model files have to be used. The output termination impedance of the
GS3490 cable driver, which is provided as an S-parameter file, can be used in the
testbench to improve the simulation results accuracy. Figure 2-2 shows a sample
simulation testbench for GS3490 cable equalizer model.
Figure 2-2: Block Diagram of a Sample Testbench to Simulate GS3490 Cable Equalizer IBIS AMI Model
RXTX
RX TX
Channel 1
Channel 2
RX
EQ_RX EQ_TX
TX
SDO_Term.s2p
Application Circuit
Channel 1
Channel 2
Cable Equalizer Model
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2.1.1 GS3490 Cable Equalizer Receiver Model
The GS3490 cable equalizer 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 2-3 shows the sequence of signal flow and the
individual parts 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.
Figure 2-3: GS3490 Cable Equalizer Receiver IBIS-AMI Model
The receiver IBIS model provides the characterized GS3490 cable equalizer 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 Equalizer 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. In these cases, the "SDI_term.s2p" s-parameter file can
be used to capture the frequency dependent input impedance of the GS3490 cable
equalizer receiver.
The GS3490 cable equalizer receiver AMI model only includes the slicer. The adaptive
equalizer and Belden cable model are not included in the AMI model and the users
should add the deterministic jitter to their test-bench based on the Belden cable length
that they are using and GS3490 datasheet. For example, if the cable length is 140m and
the data rate is 2.97Gb/s, typical output jitter and maximum output jitter are 0.2UI and
0.45UI based on GS3490 datasheet. These values should be added to the test-bench to
have more accurate results.
The GS3490 cable equalizer receiver QFN package model is provided as a 4-Port
S-parameter file (GS3490_SDI.s4p) in standard touchstone format from 0GHz to 15 GHz
with 1501 data points.
Note: The package model does not include the application circuit and an appropriate
application circuit must be used in the simulation Testbench along with the IBIS-AMI
model. A typical application circuit can be found in the GS3490 Data Sheet.
Analog
Term
QFN Package
(S-parameters)
AMIFrom Channel
IBIS-AMI Model
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2.1.2 GS3490 Cable Equalizer Transmitter IBIS-AMI Model
The GS3490 cable equalizer transmitter IBIS-AMI model consists of three parts: (1) the
Analog Driver IBIS model, (2) the Transmitter AMI model, and (3) the QFN package
model. The block diagram in Figure 2-4 shows the sequence of the signal flow and the
individual parts of the model.
Figure 2-4: GS3490 Cable Equalizer Transmitter IBIS-AMI Model
The Analog Driver IBIS model receives processed signal information from the
Transmitter AMI model and applies the analog characteristics of the GS3490 cable
equalizer transmit driver. The model is based on a single-ended non-inverting
characterization of the GS3490 cable equalizer transmitter and the EDA platform
develops a differential model from complimentary copies of the single-ended model.
The GS3490 cable equalizer Transmitter AMI model consists of OP_CTL parameter to
control the output driver swing and de-emphasis settings. The possible values for
OP_CTL parameter are listed in Table 2-1.
As stated in Section 2.2.1, a differential model is developed for the GS3490 cable
equalizer transmitter. Therefore, the GS3490 cable equalizer transmitter QFN package
model is provided as a 4-Port S-parameter file (GS3490_DDO.s4p) in standard
touchstone format from 0GHz to 15GHz with 1501 data points.
Table 2-1: OP_CTL Parameter in Transmitter AMI Model
OP_CTL Swing De-emphasis Mute
0
850mV
ppd
Off N
1
850mV
ppd
2dB N
2
850mV
ppd
4dB N
3
850mV
ppd
6dB N
4
425mV
ppd
Off N
5
425mV
ppd
2dB N
6
425mV
ppd
4dB N
7
425mV
ppd
6dB N
8
425mV
ppd
N/A Y
Analog
Term
QFN Package
(S-parameters)
AMI To Channel
IBIS-AMI Model
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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. Figure 2-5 shows a sample
simulation testbench for GS3490 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 shows the sequence of signal flow and the individual parts
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.
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.
RX
CD_RX CD_TX
TX
SDO_Term.s2p
Application Circuit
Channel 1
Channel 2
Cable Driver Model
Analog
Term
QFN Package
(S-parameters)
AMIFrom Channel
IBIS-AMI Model
GS3490
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2.2.2 GS3490 Cable Driver Transmitter Model
The GS3490 cable driver transmitter IBIS-AMI model consists of three parts: (1) the
Analog Driver IBIS model, (2) the Transmitter AMI model, and (3) the QFN package
model. The block diagram in Figure 2-7 shows the sequence of the signal flow and the
individual parts of the model.
Figure 2-7: GS3490 Cable Driver Transmitter IBIS-AMI Model
The Analog Driver IBIS model receives processed signal information from the
Transmitter AMI model and applies the analog characteristics of the GS3490 cable driver
transmit driver. Two different sub-models have been employed for different output
slew rates. The appropriate sub-model has to be selected regarding the SD_EN input pin
using the Table 2-2.
The GS3490 cable driver transmitter AMI model consists of RSET parameter to control
the output driver swing. This parameter is the same as R
SET
resistor in GS3490 Data
Sheet. For a typical 800mV
pp
output, RSET should be set to 750Ω. The RSET parameter
range is from 1.21kΩ to 576Ω which translates to 500mV
pp
to 1040mV
pp
output swing.
In order to determine the RSET value, you can use the following equation:
Where R
term
is the value of the termination resistors and V
outppSE
is the single-ended
output voltage swing. For more information regarding the R
SET
resistor, please refer to
the GS3490 Data Sheet.
As stated in Section 2.2.2, a differential model is developed for the GS3490 cable driver
transmitter. Therefore, the GS3490 cable driver transmitter QFN package model is
provided as a 4-Port S-parameter file (GS3490_SDO.s4p) in standard touchstone format
from 0GHz to 15GHz with 1501 data points.
Note: The package model does not include the application circuit and an appropriate
application circuit must be used in the simulation Testbench along with the IBIS-AMI
model. A typical application circuit can be found in the GS3490 Data Sheet.
Table 2-2: Sub-model Selection Based on the Output Slew Rate
SD_EN Rise/Fall Time Sub-Model
0 SMPTE 424M & 292M compliant sdo_HD
1 SMPTE 259M compliant sdo_SD
Analog
Term
QFN Package
(S-parameters)
AMI To Channel
IBIS-AMI Model
RSET 8
R
term
V
outppSE
-----------------------
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GS3490
User Guide Rev.0
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