The ICS581-01 is a glitch free, Phase Locked Loop (PLL) based clock multiplexer (mux) with zero delay from input to output. It has have four low skew outputs which can be configured as a single output, three outputs,or four outputs. The ICS581-01 allows user control over the mux switching. The ICS581-01 is a member of IDT’s ClockBlocksTM family of clock generation, synchronization, and distribution devices. For a non-PLL based clock mux, see the ICS580-01.