Analog Devices UG-001 Evaluation Board User Guide, Power Supplies, Input Signals, Output Signals

Evaluation Board User Guide

EVALUATION BOARD HARDWARE

The AD9272/AD9273 evaluation board provides all of the support circuitry required to operate the AD9272/AD9273 in its various modes and configurations. Figure 2 shows the typical bench characterization setup used to evaluate the ac performance of the AD9272/AD9273. 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 (see the AD9272 or AD9273 data sheet).

See the Evaluation Board Software Quick Start Procedures section to get started and Figure 21 to Figure 31 for the complete sche- matics and layout diagrams that demonstrate the routing and grounding techniques that should be applied at the system level.

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 ac to 240 V ac wall outlet at 47 Hz to 63 Hz. The other end is a 2.1 mm inner diameter jack that connects to the PCB at P701. Once on the PC board, the 6 V supply is fused and conditioned before connecting to low dropout linear regulators that supply the proper bias to each of the various sections on the board.

When operating the evaluation board in a nondefault condition, L705, L706, L707, and L709 can be removed to disconnect the switching power supply. This enables the user to bias each section of the board individually. Use P602 and P603 to connect a different supply for each section. At least one 1.8 V supply is needed with a 1 A current capability for AVDD_DUT and DRVDD_DUT; however, it is recommended that separate supplies be used for both analog and digital domains. An additional supply is also required to supply 3.0 V to the device under test, AVDD2_DUT. This should also have a 1A current capability. To operate the

UG-001

evaluation board using the SPI and alternate clock options, a separate 3.3 V analog supply is needed in addition to the other supplies. The 3.3 V supply, or AVDD_3P3V, should have a 1 A current capability.

To bias the crosspoint switch circuitry or CW section and differential gain drive circuitry, separate +5 V and −5 V supplies are required at P601. These should each have 1 A current capability. This section cannot be biased from a 6 V, 2 A wall supply. Separate supplies are required at P601.

INPUT SIGNALS

When connecting the clock and analog 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 evalu- ation board. Enter the desired frequency and amplitude (refer to the specifications in the AD9272 or AD9273 data sheet). The evaluation board is set up to be clocked from the crystal oscil- lator, OSC401.

If a different or external clock source is desired, follow the instructions Clock Circuitry section. Typically, most Analog Devices evaluation boards can accept ~2.8 V p-p or 13 dBm sine wave input for the clock. When connecting the analog input source, it is recommended to use a multipole, narrow-band band-pass filter with 50 Ω terminations. Analog Devices uses TTE and K&L Microwave, Inc., band-pass filters. The filter should be connected directly to the evaluation board.

OUTPUT SIGNALS

The default setup uses the FIFO5 high speed, dual-channel FIFO data capture board (HSC-ADC-EVALCZ). Two of the eight channels can then be evaluated at the same time. For more information on channel settings on these boards and their optional settings, visit www.analog.com/FIFO.

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