CY26049-36

CY26049 is a FailSafe frequency synthesizer with a reference clock input and three clock outputs. The device provides an optimum solution for applications where continuous operation is required in the event of a primary clock failure. The  continuous, glitch-free operation is achieved by using a DCXO which serves as a primary clock source. The FailSafe control circuit synchronizes the DCXO with the reference as long as the reference is within the pull range of the crystal.

In the event of a reference clock failure the DCXO maintains the last frequency and phase information of the reference clock. The unique feature of the CY26049-36 is that the DCXO is in fact the primary clocking source. When the reference clock is restored, the DCXO automatically re-synchronizes to the reference. The status of the reference clock input, as detected by the CY26049-36, is reported by the SAFE pin.

In the buffer mode (FS3:FS0 = 1110 or 1111), the CY26049-36 can be used as a jitter attenuator. In this mode, extensive jitter on the input clock will be "filtered", resulting in a low-jitter output clock.