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The AD9578 evaluation board is a compact, easy-to-use platform for evaluating all features of the AD9578. The AD9578 is a programmable synthesizer intended for jitter attenuation and asynchronous clocking applications in high performance telecommunications, networking, data storage, SERDES and PHY applications. The evaluation board consists of one prepopulated 49.152MHz crystal and optional single ended SMA inputs to drive the XO2 and XO4 pins. Each output is accessed through edge launch ac-coupled SMA connectors. The on board power supply allows users to simply operate the AD9578 with 2.5V or 3.3V voltages by altering a few jumper settings. Use this user guide in conjunction with the AD9578 data sheet and software documentation available at www.analog.com.
The following instructions are for setting up the physical connections to the AD9578/PCBZ evaluation board.
The AD9578/PCBZ is setup by default to power the AD9578 and remaining circuitry with 3.3V using the provided 6V wall power supply. The evaluation board can be configured to operate at 2.5V when using the 6V wall supply by removing jumpers P507 and P509.
An external power source may be connected to both the AD9578 and digital circuitry by using header P506. The AD9578 and digital circuitry must operate at the same voltage level for proper functionality. To connect an external supply:
The following instructions assume the evaluation board is set up with the default power configuration as described in the Power Connections section.
Refer to the Evaluation Board Software section for details on running the AD9578 evaluation board software.
The AD9578 evaluation board comes prepopulated with a 49.152MHz crystal (Y101) across the XO1 and XO2 pins. Crystal Y102 connects to the XO3 and XO4 pins and is not prepopulated. Any crystal between 22MHz and 54MHz in a 3.2mm x 2.5mm package is suitable but care must be taken to select the proper load capacitance to ensure oscillation.
The REFOUT output (J217 and J218) can be configured to be a copy of either XO input or a divided version of the applied REFCLK input (includes divide by 1). The frequency source of OUT1 and OUT2 is PLL1 and the source of OUT3 and OUT4 is PLL2. The logic level of each output is selectable between CMOS, HCSL, LVDS and LVPECL. All outputs are terminated as LVPECL by default and ac coupled to their respective SMA connectors. Using any logic type other than LVPECL will require modifications to the terminations. Refer to the AD9578 datasheet for the recommended termination for each logic type.
The AD9574/PCBZ default configuration allows a PC running the AD9578 evaluation software to read and write the various registers of the AD9578 via a USB connection. The user may interface with the SPI bus from an external SPI controller by removing jumpers P108-P110 and driving the appropriate signals to the SDO, SCK, CSB, and SDI nodes.
Use the following instructions to set up the AD9578 evaluation board software.
Use the following instructions to set up the AD9578 evaluation board software.
Do not connect the evaluation board until the software installation is complete.
Power up and connect the evaluation board to the PC. See the Evaluation Board Hardware section for details on the various connectors on the evaluation board. At start up, the AD9578 evaluation software checks to see if an evaluation board is connected. If no board is connected, the message in Figure 2 will appear.
Clicking OK allows the software to be used without a connected evaluation board. This mode is convenient for creating register setup files when an evaluation board is not present. If an evaluation board is present and the error message appears, check power and USB connections and re start the program. When and evaluation board is connected before starting program, the standard GUI appears as shown in Figure 6. It is possible to connect the evaluation board after the software is started by selecting File/Select Hardware after the board has been powered and USB cable connected. When a board is properly connected, Read All Successful will appear in the Comments box.
The AD9578 software allows the user to save a setup file containing all of the current register settings generated by the software, which can be later read, and re used.
To create a setup file:
To load a setup file:
Once the evaluation software is loaded and the evaluation board is connected, use the following steps to lock both PLLs on the AD9578. These steps use the on board 49.152MHz crystal as a reference for both PLL1 and PLL2 and the default power configuration using the provided 6V wall supply as described in the Evaluation Board Hardware section. The quick start guide covers only simple PLL operation. See the AD9578 datasheet and Evaluation Software Components section for a detailed explanation of the various AD9578 features. The following case is an example of the AD9578 using the values in Table 1.
Table 1. Quick Start Summary
Parameter | Value |
---|---|
Input Frequency | 49.152MHz across XO1 and XO2 |
PLL1 Reference Selection | Crystal 1 |
PLL2 Reference Selection | Crystal 1 |
OUT1 Frequency and Logic Type | 125MHz LVPECL |
OUT2 Frequency and Logic Type | 156.25MHz LVPECL |
OUT3 Frequency and Logic Type | Disabled |
OUT4 Frequency and Logic Type | 155.52MHz LVPECL |
REFOUT Frequency and Logic Type | Disabled |