ICS83905I

CRYSTAL INPUT INTERFACE
Figure 1A shows an example of ICS83905I crystal interface witha  parallel resonant crystal. The frequency accuracy can be finetuned by adjusting the C1 and C2 values. For a parallel crystalwith loading capacitance CL = 18pF, we suggest C1 = 15pF andC2 = 15pF to start with. These values may be slightly fine tunedfurther to optimize the frequency ccuracy for different board lay-outs. Slightly increasing the C1 and C2 values will slightly reducethe frequency. lightlydecreasing the C1 and C2 values will slightlyincrease the frequency. For the oscillator circuit below, R1 canbe used, but is otquired. For new designs, it is recommendedthat R1 not be used.

The ICS83905I is a low skew, 1-to-6 LVCMOS / LVTTL Fanout Buffer and a member of the HiPerClockS™ family of High Performance Clock Solutions from ICS. The low impedance LVCMOS/LVTTL outputs are designed to drive 50W series or parallel terminated transmission lines. The effective fanout can be increased from 6 to 12 by utilizing the ability of the outputs to drive two series terminated lines.

The ICS83905I is characterized at full 3.3V, 2.5V, and 1.8V, mixed 3.3V/2.5V, 3.3V/1.8V and 2.5V/1.8V output operating supply mode. Guaranteed output and part-to-part skew  characteristics along with the 1.8V output capabilities makes the ICS83905I ideal for high performance, single ended applications that also require a limited output voltage.