Q
Recently, I have bought Yours AD9952 evaluation board. I would, if possible,
more informations about the power supply that needs, particular the current
max, if is better
a linear than a switchin regulator. More over, using an external sine
oscillator for clock of DDS, is possible connect it directly into the balun or
need transformer for example by a PECL comparator.
Finally, what it mean DUT1 and DUT2 on the schematics, on Your data sheet there
aren't write, and so,
the PCB that You will send me at which DUT is refereed.
A
The power supply requirements for the same evaluation board using the AD9954
instead of AD9952 is a stable DC supply capable of generating 1.8V, 200mA. The
AD9952 will have the same requirements.
A linear regulator not a switching regulator should be used for the power
supply. Switching type regulators should generally be avoided in powering
precision analog circuits as they require special noise control techniques.
You can connect the external sine wave oscillator for the DDS clock directly to
the balun transformer. The AD9952 reference input is normally driven with a
sine wave. It is AC coupled (with a capacitor) and if a single-ended drive is
used the other clock input is decoupled with another capacitor. The drive level
must not be over 1.8 V pk-pk (0.64 V r.m.s.) with a 1.8V supply, but may be as
low as 100 mV r.m.s. However it is better to use as large a drive as possible
to minimise phase noise. The performance of the DDS system is limited by the
quality of the oscillator. The better the performance of the oscillator, the
better the DDS performance.
DUT stands for Device Under Test, it refers to the part being tested in the
evaluation board. Many evaluation boards are common to several members of a
family of devices. If you order the evaluation board for the AD9952
(AD9952/PCB), then the DUT that you will receive in your evaluation board will
be the AD9952.