ASM2I99448 Datasheet, PDF (1/15 Pages) Alliance Semiconductor Corporation – 3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer

May 2005
ASM2I99448
rev 0.3
3.3V/2.5V LVCMOS 1:12 Clock Fanout Buffer
Features
ƒ 12 LVCMOS compatible clock outputs
ƒ Selectable LVCMOS and differential LVPECL
compatible clock inputs
ƒ Maximum clock frequency of 350MHz
ƒ Maximum clock skew of 150pS
ƒ Synchronous output stop in logic low state
eliminates output runt pulses
ƒ High–impedance output control
ƒ 3.3V or 2.5V power supply
ƒ Drives up to 24 series terminated clock lines
ƒ Ambient temperature range –40°C to +85°C
ƒ 32–Lead LQFP & TQFP packaging
ƒ Supports clock distribution in networking,
telecommunication and computing applications
ƒ Pin and Function compatible to MPC9448 and
MPC948
Functional Description
The ASM2I99448 is a 3.3V or 2.5V compatible, 1:12 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.
The ASM2I99448 is specifically designed to distribute
LVCMOS compatible clock signals up to a frequency of
350MHz. Each output provides a precise copy of the input
signal with a near zero skew. The outputs buffers support
driving of 50Ω terminated transmission lines on the incident
edge: each output is capable of driving either one parallel
terminated or two series terminated transmission lines.
Two selectable, independent clock inputs are available,
providing support of LVCMOS and differential LVPECL
clock distribution systems. The ASM2I99448 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
ASM2I99448 is pin and function compatible but
performance–enhanced to the MPC948.
Alliance Semiconductor
2575, Augustine Drive • Santa Clara, CA • Tel: [phone] • Fax: [phone] • www.alsc.com
Notice: The information in this document is subject to change without notice.