AV9155 Datasheet, PDF (1/11 Pages) Integrated Circuit Systems – Low Cost 20-Pin Frequency Generator

Integrated
Circuit
Systems, Inc.
AV9155
Low Cost 20-Pin Frequency Generator
General Description
The AV9155 is a low cost frequency generator designed spe-
cifically for desktop and notebook PC applications. Its CPU
clocks provide all necessary CPU frequencies for 286, 386 and
486 systems, including support for the latest speeds of proces-
sors. The device uses a 14.318 MHz crystal to generate the
CPU and all peripheral clocks for integrated desktop
motherboards.
The dual 14.318 MHz clock outputs allows one output for the
system and one to be the input to an ICS graphics frequency
generator such as the AV9194.
The CPU clock offers the unique feature of smooth, glitch-free
transitions from one frequency to the next, making this ideal
device to use whenever slowing the CPU speed. The AV9155
makes a gradual transition between frequencies, so that it
obeys the Intel cycle-to-cycle timing specification for 486
systems. The simultaneous 2X and 1X CPU clocks offer
controlled skew to within 1.5ns (max) of each other.
ICS offers several versions of the AV9155. The different devices
are shown below:
Features
• Compatible with 286, 386, and 486 CPUs
• Supports turbo modes
• Generates communications clock, keyboard clock,
floppy disk clock, system reference clock, bus clock
and CPU clock
• Output enable tristates outputs
• Up to 100 MHz at 5V or 3.3V
• 20-pin DIP or SOIC
• All loop filter components internal
• Skew-controlled 2X and 1X CPU clocks
• Power-down option
ICS has been shipping motherboard frequency generators
since April 1990, and is the leader in the area of multiple output
clocks on a single chip. The AV9155 is a third generation
device, and uses ICS’s patented analog CMOS phase-locked
loop technology for low phase jitter. ICS offers a broad family
of frequency generators for motherboards, graphics and other
applications, including cost-effective versions with only one
or two output clocks. Consult ICS for all of your clock
generation needs.
PART
AV9155C-01
AV9155C-02
AV9155C-23
AV9155C-36
DESCRIPTION
Motherboard clock generator with 16 MHz BUS CLK
Motherboard clock generator with 32 MHz BUS CLK
Includes Pentium™ frequencies
Features a special 40 MHz SCSI clock
Block Diagram
9155 Rev B 8/24/98
Pentium is a trademark of Intel Corporation.