Analog Devices AD6659, User Manual

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Evaluation Board User Guide UG-003
Rev. A | Page 5 of 40
08
16
8-
0
03
AD9650
15 Ω
0.1µF 0.1µF
VIN+
VIN–
15 Ω
0.1µF
33 Ω
33 Ω
33 Ω
33 Ω
2V p-p
0.1µF
5pF 2.2pF
15pF
15pF
0 Ω
VCM
Figure 3. Default Analog Input Configuration of the AD9650 Family
0
81
68
-03
1
AD9268/
AD9258
66.5 Ω
0.1µF
0.1µF
VIN+
VIN–
66.5 Ω
0.1µF
33 Ω
33 Ω
2V p-p
0.1µF
0 Ω
VCM
FERRITE
BEAD
10 Ω @ 100MHz
FERRITE
BEAD
10 Ω @ 100MHz
Figure 4. Default Analog Input Configuration of the AD9268 Family
08
16
8-
0
32
AD9251/
AD9231/
AD9204
33 Ω
0.1µF
0.1µF
VIN+
VIN–
33 Ω
0.1µF
33 Ω
33 Ω
2V p-p
0.1µF
22pF
0 Ω
VCM
Figure 5. Default Analog Input Configuration of the AD9269 Family
AD9269 Family DEFAULT OPERATION AND JUMPER SELECTION
SETTINGS
For the AD9269 family, the default analog input configuration
supports analog input frequencies of up to ~150 MHz (see Figure 5).
The nominal input drive level is 10 dBm to achieve 2 V p-p full
scale into 50 Ω. At higher input frequencies, slightly higher input
drive levels are required due to losses in the front-end network.
This section explains the default and optional settings or modes
allowed on the
AD9650 / AD9268 / AD9258 / AD9251 / AD9231 /
AD9204 / AD9269 / AD6659 Rev. C evaluation board.
Power Circuitry
Optionally, the Channel A input on the board can be configured
to use the
AD8375 digitally variable gain amplifier (DVGA). The
AD8375 component is included on the evaluation board at U401.
However, the path into and out of the AD8375 can be configured in
many different ways depending on the application; therefore, the
parts in the input and output path are left unpopulated. Users
should see the AD8375 data sheet for additional information
on this part and for configuring the inputs and outputs. The
AD8375 by default is held in power-down mode but can be
enabled by adding a jumper on J403.
Connect the switching power supply that is supplied in the
evaluation kit between a rated 100 V ac to 240 V ac wall outlet
at 47 Hz to 63 Hz and P101.
Analog Input
The A and B channel inputs on the evaluation board are set up for a
double balun-coupled analog input with a 50 Ω impedance.
AD9650 Family
The default input network, as configured on the AD9650 evaluation
board, is shown in Figure 3
The Channel B input is also set up with an optional input path
through the
ADL5562 ultralow distortion RF/IF differential
amplifier. Similar to Channel A, the amplifier is included on the
board at U501; however, the input-/output-related components
are not included. Users should see the ADL5562 data sheet for
additional information on this part and for configuring the
inputs and outputs. The ADL5562 is also normally held in power-
down mode and can be enabled by adding a jumper on J503.
The ADL5562 on the Channel B input can also be substituted
with the
ADA4937 or the ADA4938 to allow evaluation of these
parts with the ADC.
AD9268 Family
For the AD9268 family, the default analog input configuration
supports analog input frequencies of up to ~250 MHz (see
Figure 4). This input network is optimized to support a wide
frequency band. See the AD9258 and AD9268 data sheets for
additional information on the recommended networks for
different input frequency ranges.