Texas Instruments ADS42 EVM Series, Руководство пользователя

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Optional Configurations
J11 and J13 are the power supply for THS4509. An on-board layout option for a LPF or BPF is available
between the amplifier and the ADC. By default the filter is bypassed to allow the user flexibility to design
according to desired specifications.
3.2 On-Board CDC72010 Clock
The default clock input configuration is 1:4 transformer coupling through T6. The optional configuration is
through clock driver CDC72010. The changes required to modify the transformer coupled clock input to
clock driver input are shown in
Table 4 .
Table 4. Jumper Setting for Transformer-Coupled or CDC72010 Input
Jumper Transformer-Coupled (Default) CDC72010
J14 shunt open
JP20 Shunt 1 2 Shunt 1 2
JP21 Shunt 1 2 Shunt 1 2
J18 open open
R121 0 ohm DNI
R122 DNI 0 ohm
SJP7 Short 1 2 Short 3 4
SJP6 Short 3 4 Short 5 6
The on-board layout is available for the option of VCXO and crystal BPF. The CDCE72010 comes with a
default configuration (see CDCE72010 data sheet (
SCAS858 ) for details about device default
configuration). With a 10MHz primary reference at J19 and a 983.04 MHz VCXO on-board the CDC
outputs a LVCMOS clock at U0P (pin7) at 245.76MHz. With a 491.52 MHz VCXO the CDC outputs a
LVCMOS clock at U0P at 122.88MHz. The clock goes through an on-board crystal BPF (Y0) and is used
as the input clock to the ADC through SJP6.
3.3 Parallel CMOS Output
The default ADC output is configured as DDR LVDS output on the EVM. The layout provides an option of
1.8v parallel CMOS output from the ADC. The changes required to modify from DDR LVDS output to
parallel CMOS output are shown in
Table 5 .
Table 5. Jumper/Component Setting for DDR LVDS Output and Parallel CMOS
Output
Jumper/Component DDR LVDS Output Parallel CMOS
U12 (SN74AVC16T245) DNI Installed
U13 (SN74AVC16T245) DNI Installed
RN5 to RN8 Installed DNI
RN9 to RN12 Installed DNI
JP26 Open Shunt
JP27 Open Shunt
The CMOS output data is output from the EVM board at 40-pin connectors J1 (ch A) and J2 (ch B).
9 SLAU333 – March 2011 ADS42xx EVM
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