The device contains two internal PLL stages that are cascaded in series. The first PLL stage attenuates the reference clock jitter by using an internal or external VCXO circuit. The internal VCXO requires the connection of an external inexpensive pullable crystal (XTAL) to the ICS813078I. This first PLL stage (VCXO PLL) uses external passive loop filter components which are used to optimize the PLL loop bandwidth and damping characteristics for the given application. The output of the first stage VCXO PLL is a stable and jitter-tolerant 30.72MHz reference input for the second PLL stage. The second PLL stage provides frequency translation by multiplying the output of the first stage up to 491.52MHz or 614.4MHz. The low phase noise characteristics of the VCXO-PLL clock signal is maintained by the internal FemtoClockTMPLL, which requires no external components or complex programming. Two independently configurable frequency dividers translate the internal VCO signal to the desired output frequencies. All frequency translation ratios are set by device configuration pins. Supported input reference clock frequencies: 10MHz, 12.8MHz, 15MHz, 15.36MHz, 20MHz, 30.72MHz, 61.44MHz, and 122.88MHz