ASM2I9940L

ASM2I9940L Low Voltage 1:18 Clock Distribution Chip Functional Description The ASM2I9940L is a 1:18 low Voltage Clock distribution chip with 2.5 V or 3.3 V LVCMOS output capabilities. The device features the capability to select either a differential LVPECL or LVCMOS compatible input. The 18 outputs are 2.5 V or 3.3 V LVCMOS compatible and feature the drive strength to drive 50 W series or parallel terminated transmission lines. With output−to−output skews of 150 pS, the ASM2I9940L is ideal as a clock distribution chip for the most demanding of Synchronous systems. The 2.5 V outputs also make the device ideal for supplying clocks for a high performance microprocessor based design. With low output impedance (≈20 W), in both the HIGH and LOW logic states, the output buffers of the ASM2I9940L are ideal for driving series terminated transmission lines. With a 20 W output impedance the ASM2I9940L has the capability of driving two series terminated lines from each output. This gives the device an effective fanout of 1:36. The differential LVPECL inputs of the ASM2I9940L allow the device to interface directly with a LVPECL fanout buffer to build very wide clock fanout trees or to couple to a high frequency clock source. The LVCMOS input provides a more standard interface for applications requiring only a single clock distribution chip at relatively low frequencies. In addition, the two clock sources can be used to provide for a test clock interface as well as the primary system cl...