FemtoClock Crystal-to-3.3V LVPECL Frequency Synthesizer

The 843242 is a 2 differential output LVPECL Synthesizer designed to generate Ethernet reference clock frequencies. Using a 31.25MHz or 26.041666MHz, 18pF parallel resonant crystal, the following frequencies can be generated based on the settings of 4 frequency select pins (SEL[A1:A0], SEL[B1:B0]): 625MHz, 312.5MHz, 156.25MHz, and 125MHz.

The two banks have their own dedicated frequency select pins and can be independently set for the frequencies mentioned above. The 843242 our 3rd generation low phase noise VCO technology and can achieve 1ps or lower typical rms phase jitter, easily meeting Ethernet jitter requirements. The 843242 is packaged in a small 16-pin TSSOP package.