Evaluation Board Hardware; Power Supplies; Clock Signals; Input Signals - Analog Devices AD911 Series User Manual

Evaluation Board User Guide

EVALUATION BOARD HARDWARE

The AD911x and AD971x evaluation boards provide all of the
support circuitry required to operate the AD911x and AD971x
in their various modes and configurations. Figure 1 shows the
typical bench characterization setup used to evaluate the ac
performance of the AD911x and AD971x. It is critical that
the signal source used for the clock have very low phase noise
(<1 ps rms jitter) to realize the optimum performance of the signal
chain. A low noise and low distortion spectrum analyzer is also
necessary to evaluate the analog output correctly.
See the Evaluation Board Software: Quick Start Procedures
section to get started.

POWER SUPPLIES

This evaluation board can be powered via the USB interface or
with an external 5 V power supply. By default, the USB powered
option is selected.
By default, on-board voltage regulators are selected to supply
power to the AD911x and AD971x as well as its supporting
circuitry. These regulators can be configured to supply 1.8 V
or 3.3 V to the different power supply pins of the AD911x or
AD971x, with 3.3 V selected by default.
The current from each of the power pins can be tested by using
JP54 (AVDD), JP6/JP78 (CVDD), and JP10/JP15 (DVDD). The
nominal values of the AVDD, CVDD, and DVDD currents for
the AD971x board are 9.5 mA, 2.8 mA, and 13.1 mA, respec-
tively. For the AD911x board, the nominal AVDD, CVDD,
and DVDD currents are 50.3 mA, 2.8 mA, and 12.1 mA,
respectively.
Voltages can be checked at each pin at the corresponding
test points listed; TP5 (AVDD), TP12/TP24 (CVDD), and
2 × DATA CLOCK
DPG2
USB
I AND Q DATA 14
Figure 1. Evaluation Board Connection
Rev. 0 | Page 3 of 12
TP13/TP8 (DVDD), with grounds at TP6, TP14, TP23, TP4,
and TP9. All voltages should show a reading of around 3.3 V
with the factory default jumper settings as mentioned. These
voltages can be changed to 1.8 V by switching JP22, JP26, JP29,
JP88, and JP89 to shunt Pin 2 and Pin 3. Alternatively, external
power supplies can be used to supply the AD911x or AD971x
and its supporting circuitry.
When using the ADL5375 modulator on board for testing
combined performance, a 5 V power supply must be connected
to the ADL5375 POWER (TP16) with a ground at TP21 for
that part.

CLOCK SIGNALS

When connecting the clock source, use clean signal generators
with low phase noise, such as Rohde & Schwarz SMA or HP8644B
signal generators or the equivalent. Use a 1 m, shielded, RG-58,
50 Ω coaxial cable for making connections to the evaluation
board. Enter the desired frequency and amplitude (refer to the
specifications in the AD9114/AD9115/AD9116/AD9117
AD9714/AD9715/AD9716/AD9717
board is set up to be clocked from an external source and the
internal clock distribution IC AD9512.

INPUT SIGNALS

The 14-bit wide data bus is intended to be driven by the DPG2
evaluation platform directly. The DPG2 is capable of driving a
16-bit wide bus. Because the AD911x and AD971x are 14-bit
devices, the DPGDownloader software compensates for the
different resolution parts by automatically bit shifting the
patterns generated to align properly with the DAC. The reso-
lution for patterns needed is controllable through the software.
DAC CLOCK
SOURCE
AD911x/AD971x
DATA CLOCK
EVALUATION BOARD
USB
SPECTRUM
ANALYZER
UG-073
or
data sheets). The evaluation
AQM LO CLOCK
SOURCE
(OPTIONAL)