GS3490
User Guide
Rev.0
PDS-060922
January 2015
6 of 7
Propietary & Confidential
www.semtech.com
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 750
Ω
. The RSET parameter
range is from 1.21k
Ω
to 576
Ω
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
-----------------------
⎝
⎠
⎛
⎞
×
=
