The CY29947 is a low-voltage 200-MHz clock distribution buffer with the capability to select one of two LVCMOS/LVTTL compatible clock inputs. The two clock sources can be used to provide for a test clock as well as the primary system clock. All other control inputs are LVCMOS/LVTTL compatible. The 9 outputs are LVCMOS or LVTTL compatible and can drive 50 series or parallel terminated transmission lines.For series terminated transmission lines, each output can drive one or two traces giving the device an effective fanout of 1:18. The outputs can also be three-stated via the three-state input TS#. Low output-to-output skews make the CY29947 an ideal clock distribution buffer for nested clock trees in the most demanding of synchronous systems. The CY29947 also provides a synchronous output enable input for enabling or disabling the output clocks. Since this input is internally synchronized to the input clock, potential output glitching or runt pulse generation is eliminated.