ASM2I9940L

June 2005 ASM2I9940L rev 1.0 Low Voltage 1:18 Clock Distribution Chip Features ƒ LVPECL or LVCMOS Clock Input ƒ 2.5V LVCMOS Outputs for Pentium II Microprocessor Support* ƒ 150pS Maximum Output-to-Output Skew ƒ Maximum Output Frequency of 250MHz ƒ 32 Lead LQFP & TQFP Packaging ƒ Dual or Single Supply Device: ƒ Dual VCC Supply Voltage, 3.3V Core and 2.5V Output ƒ Single 3.3V VCC Supply Voltage for 3.3V Outputs ƒ Single 2.5V VCC Supply Voltage for 2.5V I/O ƒ Pin and Function compatible to MPC940L, MPC9109, CY29940 and CY29940-1 Functional Description The ASM2I9940L is a 1:18 low Voltage Clock distribution chip with 2.5V or 3.3V LVCMOS output capabilities. The device features the capability to select either a differential LVPECL or LVCMOS compatible input. The 18 outputs are 2.5V or 3.3V LVCMOS compatible and feature the drive strength to drive 50Ω series or parallel terminated transmission lines. With output-to-output skews of 150pS, the ASM2I9940L is ideal as a clock distribution chip for the most demanding of Synchronous systems. The 2.5V outputs also make the device ideal for supplying clocks for a high performance microprocessor based design. With low output impedance (≈20Ω), in both the HIGH and LOW logic states, the output buffers of the ASM2I9940L are ideal for driving series terminated transmission lines. With a 20Ω output impedance the ASM2I9940L has the capability of driving two series terminated lines from each output. This gives the device an effective fanout o...