ASM2I9942C

The ASM2I9942C is a 1:18 low voltage clock distribution chip with 2.5V or 3.3V LVCMOS output capabilities. The device is offered in two versions; the ASM2I9942C has an LVCMOS input clock while the ASM2I9942P has an LVPECL input clock. 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 outputtooutput skews of 200pS, the ASM2I9942C 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 Pentium II TM microprocessor based design.

With a low output impedance (12Ω), in both the HIGH and LOW logic states, the output buffers of it are ideal for driving series terminated transmission lines. With an output impedance of 12Ω, the ASM2I9942C can drive two series terminated transmission lines from each output. This capability gives the ASM2I9942C an effective fanout of 1:36. The ASM2I9942C provides enough copies of low skew clocks for most high performance synchronous systems.

The LVCMOS/LVTTL input of the ASM2I9942C provides a more standard LVCMOS interface. The OE pins will place the outputs into a high impedance state. The OE pin has an internal pullup resistor.

The ASM2I9942C is a single supply device. The VCC power pins require either 2.5V or 3.3V. The 32lead TQFP and LQFP package is chosen to optimize performance, board space and cost of ASM2I9942C. The 32lead TQFP has a 7x7mm2 body size with a conservative 0.8mm pin spacing.