Datasheet

Evaluation Board User Guide UG-290
Rev. 0 | Page 3 of 28
EVALUATION BOARD HARDWARE
The evaluation board provides all of the support circuitry
required to operate the AD9434 and AD9484 in their various
modes and configurations. Figure 2 shows the typical bench
characterization setup used to evaluate the ac performance. It is
critical that the signal sources used for the analog input and
clock have very low phase noise (<1 ps rms jitter) to realize the
optimum performance of the signal chain. Proper filtering of the
analog input signal to remove harmonics and lower the
integrated or broadband noise at the input is necessary to achieve
the specified noise performance.
The evaluation board covers both the AD9484 and AD9484
ADCs. See the Evaluation Board Software Quick Start
Procedures section to get started, and see Figure 15 to Figure 28
for the complete schematics and layout diagrams. These
diagrams illustrate the routing and grounding techniques that
should be applied at the system level when designing
application boards using these converters.
POWER SUPPLIES
This evaluation board comes with a wall-mountable switching
power supply that provides a 6 V, 2 A maximum output. Connect
the supply to the rated 100 V to 240 V ac wall outlet at 47 Hz to
63 Hz. The output from the supply is provided through a
2.1 mm inner diameter jack that connects to the printed circuit
board (PCB) at J300. The 6 V supply is fused and conditioned
on the PCB before connecting to the low dropout linear regulators
(default configuration) that supply the proper bias to each of the
various sections on the board.
The evaluation board can be powered in a nondefault condition
using external bench power supplies. To do this, JP301 through
JP303 can be removed to disconnect the outputs from the on-
board LDOs. This enables the user to bias each section of the
board individually. Use P300 and P301 to connect a different
supply for each section. A 1.8 V supply is needed with a 1 A
current capability for DUT_AVDD and DRVDD; however, it is
recommended that separate supplies be used for both analog and
digital domains. To operate the evaluation board using the SPI
and alternate clock options, a separate 3.3 V analog supply is
needed in addition to the other supplies. This 3.3 V supply
should have a 1 A current capability.
An additional 5V_AVDD supply is used to bias the optional
input path amplifier. If used, this supply should have a 1 A current
capability.
INPUT SIGNALS
When connecting the clock and analog source, use clean signal
generators with low phase noise, such as the Rohde & Schwarz SMA
or HP 8644B signal generators or an equivalent. Use a 1 meter,
shielded, RG-58, 50 Ω coaxial cable for connecting to the
evaluation board. Enter the desired frequency and amplitude in
the signal generators (see the Specifications section in the data
sheet of the respective part). When connecting the analog input
source, use of a multipole, narrow-band band-pass filter with 50 Ω
terminations is recommended. Analog Devices, Inc., uses TTE,
Allen Avionics, and K&L band-pass filters. The filters should be
connected directly to the evaluation board.
If an external clock source is used, it should also be supplied
with a clean signal generator as previously specified. Typically,
most Analog Devices evaluation boards can accept ~2.8 V p-p or
13 dBm sine wave input for the clock.
OUTPUT SIGNALS
The default setup uses the Analog Devices high speed converter
evaluation platform (HSC-ADC-EVALCZ) for data capture.
The LVDS output signals are routed to the FPGA on the data
capture board.