AD9772A Analog Devices, AD9772A Datasheet - Page 31

• Manufacturer Part Number: AD9772A
• Manufacturer: Analog Devices

Specifications of AD9772A

• Resolution (bits): 14bit
• Dac Update Rate: 160MSPS
• Dac Settling Time: 11ns
• Max Pos Supply (v): +3.6V
• Single-supply: Yes
• Dac Type: Current Out
• Dac Input Format: Par

Regardless of which image is selected for a given application, the
adjacent images must be sufficiently filtered. In most cases, a SAW
filter providing differential inputs represents the optimum device
for this purpose. For single-ended SAW filters, a balanced-to-
unbalanced RF transformer is recommended. The high output
impedance of the AD9772A provides a certain amount of
flexibility in selecting the optimum resistive load, R
as any matching network.
For many applications, the data update rate for the DAC (that is,
f
clock (for example, GSM − 13 MHz). Furthermore, these
applications prefer to use standard IF frequencies, which offer a
large selection of SAW filter choices with various pass bands
(for example, 70 MHz). In addition, these applications may
benefit from the AD9772A’s direct IF mode capabilities when used
in conjunction with a digital upconverter, such as the AD6622.
Because the AD6622 can digitally synthesize and tune up to four
modulated carriers, it is possible to judiciously tune these carriers
in a region falling within the pass band an IF filter while the
AD9772A is reconstructing a waveform. Figure 59 shows an
example in which four carriers are tuned around 18 MHz with a
digital upconverter operating at 52 MSPS such that when
reconstructed by the AD9772A in the IF mode, these carriers fall
around a 70 MHz IF.
DATA
) must be a fixed integer multiple of a system reference
LOAD
, as well
Rev. C | Page 31 of 40
Figure 59. Spectral Plot of Four Carriers at 60 MHz IF with f
–110
–10
–20
–30
–40
–50
–60
–70
–80
–90
66
68
FREQUENCY (MHz)
PLLVDD = 0
70
72
AD9772A
DATA
74
= 52 MSPS,