Datasheet

EVAL-AD5930EB
Rev. 0 | Page 3 of 12
HARDWARE DESCRIPTION
POWER SUPPLIES
The AD5930 device has two analog power supply inputs: AVDD
(Analog VDD) and AGND (Analog GND). There are also two
digital supplies on the part, DVDD (Digital VDD) and DGND
(Digital GND). Both of these supplies are independent of each
other and can be powered from 2.3 V to 5.5 V.
As well as supplying the digital supply for the
AD5930, DVDD
is used to provide the supply for the 50 MHz oscillator and the
ADG774 quad 2:1 mux.
There are two options available to power the AD5930
evaluation board:
• The USB port of a computer
• A power supply
The default option for powering the board is from the USB port
(LK1 and LK8 are in Position B). Alternatively, 2-pin terminal
blocks are available to the user for use with an external power
supply.
The 5 V from the USB port is regulated to 3.3 V, which provides
power for the CY7C68013 USB controller and related USB
circuitry. The USB port also provides the GND connections for
the board.
When LK1 is in Position B, DVDD is supplied with 3.3 V from
the regulator. When LK8 is in Position B, AVDD is powered
from DVDD through ferrite bead L1 (600 Ω @ 100 MHz).
When LK1 and LK8 are in Position A, the terminal blocks are
used to provide power to the board. Note that if you need to
operate the part at a different supply than up to 3.3 V, the
terminal blocks should be used. In addition, to abide by the
maximum ratings of the
AD5930, the board should be used as a
standalone board if operating at a voltage less than 3 V.
Therefore, SCLK, SDATA, FSYNC, CTRL, INTERRUPT, and
STANDBY must be externally supplied by the user.
DGND and AGND are connected under the
AD5930.
Therefore, it is recommended not to connect AGND and
DGND elsewhere in the system. AVDD and DVDD are
decoupled to the relevant ground plane using 10 µF and 0.1 µF
ceramic capacitors at their source and again at the
AD5930.