AD9858/FDPCB Analog Devices Inc, AD9858/FDPCB Datasheet - Page 28

• Manufacturer Part Number: AD9858/FDPCB
• Description: BOARD EVAL FOR AD9858/FD
• Manufacturer: Analog Devices Inc

Specifications of AD9858/FDPCB

• Rohs Status: RoHS non-compliant
• Design Resources: Low Jitter Sampling Clock Generator for High Performance ADCs Using AD9958/9858 and AD9515 (CN0109)
• Lead Free Status / Rohs Status: Not Compliant

AD9858
EVALUATION BOARDS
The AD9858 has three different evaluation board designs. The
first design is the traditional DDS evaluation board (see Figure 38).
In this design, the DDS is clocked and the output is taken
directly from the DAC. The analog mixer and PLL blocks are
made available for separate evaluation.
The second design is a fractional divide loop (see Figure 39).
This evaluation board was designed to incorporate the DDS, the
phase frequency detector, and the charge pump. In this
application, the DDS is used in a PLL loop. Unlike a fixed
divider used in traditional PLL loops, the output signal is
divided and fed back to the phase frequency detector by the
DDS. To do this, the output signal of the PLL loop is fed to the
DDS as REFCLK. The DDS is programmed to match the
reference input frequency. Because the DDS output frequency
can take on 2
the PLL loop output frequency, this enables frequency
resolution on the order of 470 MHz, assuming a PLL loop
output frequency of 2 GHz.
32
potential values between 0 Hz and one-half of
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The third design is a translation loop or offset loop (see Figure 37).
In this design, the analog mixer is incorporated into the feedback
path of the loop. This allows direct up-conversion to the
transmission frequency.
The three evaluation boards have separate schematics, BOMs, and
instructions. See
Table 13. Evaluation Boards for the AD9858
Model
AD9858/PCBZ
AD9858/FDPCB
AD9858/TLPCBZ
www.analog.com/dds
Description
AD9858 Frequency Synthesizer Board
AD9858 Fractional Divide Loop Frequency
Synthesizer Board
AD9858 Translation Loop Frequency
Synthesizer Board
for more information.