|Adafruit Si5351 module|
By the way, there are also some versions of the Si5351 that have 8 independent outputs instead of 3, if you really need that many.
The test setup included an Arduino Duemilanove with the NT7S library, an Adafruit Si5351 module and a Tektronix 2225 oscilloscope. I used the middle output for the test (CLK1), which was terminated with a 75ohm load. Oscilloscope vertical scale is 0.1V/div and horizontal scale is adjusted depending on frequency.
First test, 100kHz output:
|Si5351 output at 100kHz|
Output looks like a clean square wave, with a nice rise time. Peak to peak amplitude is about 650mV into 75ohm, which puts the power output at 0.7mW (-1.5dBm).