May 2005

ASM2I99447

rev 0.3

Alliance Semiconductor

2575, Augustine Drive

• Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com

Notice: The information in this document is subject to change without notice.

3.3V/2.5V 1:9 LVCMOS Clock Fanout Buffer

Features

9 LVCMOS Compatible Clock Outputs

2 Selectable, LVCMOS Compatible Inputs

Maximum Clock Frequency of 350 MHz

Maximum Clock Skew of 150 pS

Synchronous Output Stop in Logic Low State

Eliminates Output Runt Pulses

High–Impedance Output Control

3.3V or 2.5V Power Supply

Drives up to 18 Series Terminated Clock Lines

Ambient Temperature Range –40°C to +85°C

32 Lead LQFP and TQFP Packaging

Supports

Clock

Distribution

in

Networking,

Telecommunications and Computer Applications

Pin and Function Compatible to MPC947 and

MPC9447

Functional Description

The ASM2I99447 is a 3.3V or 2.5V compatible, 1:9 clock

fanout buffer targeted for high performance clock tree

applications. With output frequencies up to 350 MHz and

output skews less than 150 pS, the device meets the needs

of most demanding clock applications.

ASM2I99447 is specifically designed to distribute LVCMOS

compatible clock signals up to a frequency of 350 MHz.

Each output provides a precise copy of the input signal with

a near zero skew. The outputs buffers support driving of

50

Ω terminated transmission lines on the incident edge:

each is capable of driving either one parallel terminated or

two series terminated transmission lines.

Two selectable independent LVCMOS compatible clock

inputs are available, providing support of redundant clock

source systems. The ASM2I99447 CLK_STOP control is

synchronous to the falling edge of the input clock. It allows

the start and stop of the output clock signal only in a logic

low state, thus eliminating potential output runt pulses.

Applying the OE control will force the outputs into high

impedance mode.

All inputs have an internal pull–up or pull–down resistor

preventing unused and open inputs from floating. The

device supports a 2.5V or 3.3V power supply and an

ambient temperature range of –40°C to +85°C. The

ASM2I99447

is

pin

and

function

compatible

but