Analog Devices AD911 Series User Manual page 5

Evaluation Board User Guide
Clock Circuitry
By default, the evaluation board is set up to have a clock
input on J10 that is distributed on the evaluation board via the
clock distribution IC AD9512. One output of the AD9512 is
configured to be used as a DAC clock input and a data clock
input for the AD911x or AD971x while another one is intended
to the data generation synchronization of the DPG2. For proper
operation, the clock sent to the DPG2 evaluation board should
be configured to be twice the frequency of the clock sent to the
DUT (see Figure 4).
The evaluation board can also be set up to use an on-board
oscillator or a clock without using the clock distribution IC by
changing jumper settings. This set up cannot be used with the
DPG2 as it requires a data pattern generation board capable of
synchronizing to both edges of the clock input.
Table 2. Clock Jumpers
External Clock and
Clock Source AD9512 Default
DAC Clock Input OUT0 from
DAC Data Clock Input
OUT0 from
DPG2 Clock Output OUT2 from
S5 –
J10 Clock input
R64 On
R65 On
R66 Off
R67 On
R34 On
R110 Off
1
R122 On
1
Required for the AD9512.
DAC Full-Scale Adjust/Auxiliary DAC Output
The AD911x and AD971x full-scale current output can be
adjusted by changing the I and Q R
resistors can be either external or internal to the AD911x or
AD971x (see the AD9114/AD9115/AD9116/AD9117
AD9714/ AD9715/AD9716/AD9717
By default, the AD911x and AD971x are configured to use
external resistors to set the DAC full-scale current. By default,
the AD971x jumpers are populated to have both DACs set for
a 2 mA output current while the AD911x DACs are set for a
20 mA output. Alternatively, the on-chip IR
resistors can be used by setting the corresponding enable bit
and xR register value in the SPI software (see Section VI in
SET
the SPI section).
External Clock
AD9512 External clock
AD9512 External clock
AD9512 External clock
Clock input
–
On
Off
On
On
On
On
On
resistor values. These
SET
or
data sheets.)
and QR
SET SET
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On the evaluation board, three jumpers for each DAC select the
configuration and maximum DAC current as shown in Table 3.
Table 3. DAC Current Full-Scale Jumpers
DACI
Jumper
Setting Full-Scale Current
AD971x : 4 mA
JP9 On
AD911x: 20 mA
JP8 Off
JP7 Off
JP9 Off AD971x : 2 mA
JP8 On AD911x: 16 mA
JP7 Off
JP9 Off AD971x : 1 mA
JP8 Off AD911x: 8 mA
JP7 On
JP9 Off AD971x:1 to 4 mA
JP8 Off AD911x: 8 to 20 mA
JP7 Off depending on IR
SET
register value
Auxiliary DAC Outputs
If the AD911x or AD971x is configured to use the internal xR
resistors, the evaluation board can be configured to output the
auxiliary DACs voltages on SMA connectors (see Table 4).
Table 4. Auxiliary DAC Configuration Jumpers
Jumper Setting Additional Setting
JP9 Off; JP8 Off R97 < 2 kΩ
JP7 Off; JP12 On S9 voltage = AUXI current × R97
JP90 On
JP20 Off; JP16 Off R100 < 2 kΩ
JP21 Off; JP77 On S10 voltage = AUXQ current × R100
JP91 On
The main use of the AUX DACs is to provide a simple way to
perform LO suppression so that it does not interfere with the
performance of the part, especially at lower IF frequencies. A
more detailed description and instructions on how to calibrate
the AUX DACs appropriately are found in the SPI section.
Evaluation Board Hardware Setup for Auxiliary DACs
Follow these steps to set up the evaluation board hardware for
auxiliary DACs:
1. Enable internal bias resistors and remove external jumpers.
2. Leave JP3, JP25, JP27, and JP28 unsoldered.
3. Connect the AUX DACs with a fly wire as follows:
•
TP1 and TP44 (AUX1 DAC)
•
TP17 and TP45 (AUX2 DAC)
Analog Outputs
The evaluation board provides the option to evaluate the DAC
analog output in a variety of ways: direct DAC output (default),
buffered single-ended output, or high frequency output via
quadrature modulator. Changing the setting of a few jumpers
allows choosing among these options.
UG-073
DACQ
Jumper
Setting Full-Scale Current
JP20 On AD971x : 4 mA
JP16 Off AD911x: 20 mA
JP21 Off
JP20 Off AD971x : 2 mA
JP16 On AD911x: 16mA
JP21 Off
JP20 Off AD971x : 1 mA
JP16 Off AD911x: 8 mA
JP21 On
JP20 Off AD971x:1 to 4 mA
JP16 Off AD911x: 8 to 2 mA
JP21 Off depending on
QR register value
SET
SET