The XR81411 is a Quad Clock synthesizer with 4 independent PLLs in a compact LGA-45 package. Each synthesizer generates ANY frequency in the range of 10 MHz to 800MHz by utilizing a highly flexible delta sigma modulator and a wide ranging VCO. The outputs are independently configurable for single ended LVCMOS or differential LVDS or LVPECL. The clock outputs have very low typical phase noise jitter of sub 0.6ps RMS, while consuming extremely low power. The XR81411 uses a single reference and provides 4 independent outputs that can be configured as needed to support a wide variety of applications.
Each of the XR81411’s 4 independent PLLs include an integer/fractional divider, LVCMOS/LVDS/LVPECL output driver, 3.3V/2.5V supply, and generates one of four selectable output frequencies from a single reference. The XR81411 is optimized for use with a fundamental mode 10MHz to 60MHz crystal (or system clock) and generates a selection of output frequencies ranging from 10MHz to 800MHz in either integer or fractional mode. In fractional mode, frequency resolution of better than 2Hz steps can be achieved.
The application diagram shows a typical LAN synthesizer configuration with any standard crystal oscillating in fundamental mode.
The typical phase noise plot shows the jitter integrated over the 12KHz to 20MHz range that is widely used in these systems.