The 879893I is a PLL clock driver designed specifically for redundant clock tree designs. The device receives two LVCMOS/LVTTL clock signals from which it generates 12 new LVCMOS/LVTTL clock outputs. External PLL feedback is used to also provide zero delay buffer performance. The 879893I Intelligent Dynamic Clock Switch (IDCS) circuit continuously monitors both input CLK signals. Upon detection of a failure (CLK stuck HIGH or LOW for at least 1 period), the nALARM for that CLK will be latched (LOW). If that CLK is the primary clock, the IDCS will switch to the good secondary clock and phase/frequency alignment will occur with minimal output phase disturbance.