Datasheet

AD9772A
Rev. C | Page 28 of 40
optimum performance. Care should be taken to ensure that the
ground plane is uninterrupted over crucial signal paths. On the
digital side, this includes the digital input lines running to the
DAC. On the analog side, this includes the DAC output signal,
the reference signal, and the supply feeders.
The use of wide runs or planes in the routing of power lines is
also recommended. This serves the dual role of providing a low
series impedance power supply to the part and allowing some
capacitive decoupling to the appropriate ground plane. It is
essential that care be taken in the layout of signal and power
ground interconnections to avoid inducing extraneous voltage
drops in the signal ground paths. It is recommended that all
connections be short, direct, and as physically close to the
package as possible to minimize the sharing of conduction
paths between different currents. When runs exceed an inch in
length, use of strip line techniques with proper termination
resistors should be considered. The necessity and value of these
resistors depends on the logic family used.
For a more detailed discussion of the implementation and
construction of high speed, mixed-signal printed circuit boards,
refer to the AN-333 Application Note.