The Si552 dual frequency VCXO utilizes Silicon Laboratories advanced DSPLL circuitry to provide a very low jitter clock for all output frequencies. The Si552 is available with any-rate output frequency from 10 to 945 MHz and selected frequencies to 1400 MHz. Unlike traditional VCXO's where a different crystal is required for each output frequency, the Si552 uses one fixed crystal frequency to provide a wide range of output frequencies. This IC based approach allows the crystal resonator to be optimized for superior frequency stability and reliability. In addition, DSPLL clock synthesis provides superior supply noise rejection, simplifying the task of generating low jitter clocks in noisy environments often found in communication systems. The Si552 IC based VCXO is factory configurable for a wide variety of user specifications including frequency, supply voltage and output format. Specific configurations are factory programmed into the Si552 at time of shipment, thereby eliminating the long lead times associated with custom oscillators.