AD9642/AD9634/AD6672 User Guide
UG-386
Rev. A | Page 3 of 26
EVALUATION BOARD HARDWARE
The
evaluation board provides
all of the support circuitry required to operate these parts in
their various modes and configurations. Figure 2 shows the
typical bench characterization setup used to evaluate the ac
performance of the
, or
. It is critical
that the signal sources used for the analog input and the clock
have very low phase noise (<1 ps rms jitter) to realize the opti-
mum performance of the signal chain. Proper filtering of the
analog input signal to remove harmonics and lower the inte-
grated or broadband noise at the input is necessary to achieve
the specified noise performance.
See the Evaluation Board Software Quick Start Procedures section
to get started, and see Figure 18 to Figure 29 for the complete
schematics and layout diagrams. These diagrams demonstrate
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, 2.5 A maximum output. Connect
the supply to a rated 100 V ac 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 P201. 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, remove the
jumpers on the P104, P107, P108, and P105 header pins to
disconnect the outputs from the on-board LDOs. This enables the
user to bias each section of the board individually. Use P202
and P203 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. An additional supply
is also required to supply 1.8 V for digital support circuitry on
the board, DVDD. This should also have a 1 A current capability
and can be combined with DRVDD with little or no degradation
in performance. 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, or
3P3V_ANALOG, should have a 1 A current capability. This
3.3 V supply is also used to support the optional input path
amplifier (
) on Channel A and Channel B.
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 m
shielded, RG-58, 50 Ω coaxial cable for connecting to the evalua-
tion board. Enter the desired frequency and amplitude (see the
Specifications section in the data sheet of the respective part).
WALL OUTLET
100V TO 240V AC
47Hz TO 63Hz
SWITCHING
POWER
SUPPLY
SWITCHING
POWER
SUPPLY
SIGNAL
SYNTHESIZER
SIGNAL
SYNTHESIZER
OPTIONAL CLOCK SOURCE
ANALOG
FILTER
PC
RUNNING ADC
ANALYZER
OR VISUAL ANALOG
USER SOFTWARE
6V DC
2.5A MAX
6V DC
2.5A MAX
10
59
3-
00
2
Figure 2. Evaluation Board Connection
