Si5317-EVB

4

Rev. 0.1

2.3. Output Clock

The clock outputs are AC-coupled and are available on SMAs J5, J7, J9 and J11. For LVCMOS outputs, it might be

desirable to replace the AC coupling capacitors (C9,C14,C17, and C20) with 0

 resistors. Also, if greater drive

strength is desired for an LVCMOS output, R6 and R10 can be installed.

2.4. Pin Configuration

J12 is the large jumper header in the center left of the board that implements the jumper plugs that configure the

pins of the Si5317. Each pin can be strapped to become either H, M, or L. The H level is achieved by installing a

jumper plug between the appropriate middle row pin and its VDD row pin. L is achieved by installing a jumper plug

between the appropriate middle row pin and its GND row pin. M is achieved by installing no jumper plug.

2.5. Evaluation Board Power

The EVB can be powered from two possible sources: USB or external supplies. A 3.3 V supply is required to run

the LEDs because of their rather large forward drop. The Si5317 power supply can be separated from the 3.3 V

supply so that the Si5317 can be evaluated at a voltage other than 3.3 V. It is important to note that when the USB

supply is being used, the EVB uses the USB port only for power and that the resulting power supply is strictly 3.3 V.

Here are the instructions for the various possibilities:

2.5.1. External Power Supplies

Install a jumper between J16.1 and J16.2 (labeled EXT).

There should be no USB connection.

If the Si5317 is not being operated at 3.3 V, two supplies should be connected to J14. Connect the 3.3 V supply to

J14.1 and J14.2 (labeled 3.3 V and GND). Connect the SI5317 power supply between J14.2 and J14.3 (labeled

GND and DUT).

If the Si5317 is to be operated at 3.3 V, J15 (labeled ONE PWR) can be installed, requiring only one external

supply. Connect 3.3 V power between J14.2 and J14.3 (labeled GND and DUT).

2.5.2. USB Power

Install a jumper between J16.2 and J16.3 (labeled USB).

Install a jumper at J15 (labeled ONE PWR).

With a USB cable, plug the EVB into a powered USB port.

2.5.3. USB 3.3V Power, External Si5317 Power

Install a jumper between J16.2 and J16.3 (labeled USB).

No jumper at J15 (labeled ONE PWR).

Connect the Si5317 power supply between J14.2 and J14.3 (labeled GND and DUT).