The 551 is a low cost, high-speed single input to four output clock buffer. Part of Renesas' ClockBlocksTM family, this is our lowest cost, small clock buffer. See the 552-02B for monolithic dual version of the 551 in a 20 pin QSOP. IDT makes many non-PLL and PLL based low skew output devices as well as Zero Delay Buffers to synchronize clocks. Contact Renesas for all of your clocking needs.