2代3代时钟发生器SL28SRC01

　　• Low power PCI Express Gen 2 & Gen 3clock generator • One100-MHz differential SRC clocks • Low power push-pull output buffers （no 50ohm to ground needed） • Integrated 33ohm series termination resistors • Low jitter （《50pS） • SSON input for enabling spread spectrum clock • Triangular Spread Spectrum profile for maximum electromagnetic interference （EMI） reduction • Input frequency of 14.318MHz • Industrial Temperature -40oC to 85oC • 3.3V power supply • 16-pin TSSOP package

　　The SL28SRC01 requires a Parallel Resonance Crystal. Substituting a series resonance crystal causes the SL28SRC01 to operate at the wrong frequency and violates the ppm specification. For most applications there is a 300-ppm frequency shift between series and parallel crystals due to incorrect loading. Crystal Loading Crystal loading plays a critical role in achieving low ppm performance. To realize low ppm performance， use the total capacitance the crystal sees to calculate the appropriate capacitive loading （CL）。 Figure 1 shows a typical crystal configuration using the two trim capacitors. It is important that the trim capacitors are in series with the crystal. It is not true that load capacitors are in parallel with the crystal and are approximately equal to the load capacitance of the crystal.