Integrated

Circuit

Systems, Inc.

General Description

Features

XTAL

OSC

PCLK

UCLK

MCLK

PLL

CLOCK

GEN

÷8

X2

14.7456

MHz

X1

PD

•

Generates the 14.7456 MHz microcontroller, 40.320

MHz datadump and 1.84320 UART clocks

•

Less than ±80 ppm frequency variation including

temperature, voltage, load and aging tolerances

•

Single crystal reference minimizes crystal reliability

and inventory issues

•

80 ps one sigma jitter maintains 16-bit performance

•

Output rise/fall times less than 1.5 ns

•

On-chip loop filter components

•

3.0 V - 5.5 V supply range

•

8-pin, 150-mil SOIC package

Applications

•

Specifically designed to support the high performance

of fax/data modems

9117-01 RevA 052297P

Pentium is a trademark of Intel Corporation

PowerPC is a trademark of Motorola Corporation

Frequency Generator for Modem Systems

ICS9117-01

The ICS9117-01 is a low-cost, high-performance frequency

generator designed to support fax/data modem systems.

Datapump and UART clocks are synthesized from a

microcontroller crystal using high-accuracy, low-jitter PLLs,

meeting the frequency tolerance and -96dB signal-to-noise

ratios required by 16-bit DSP modem systems. Fast output

clock edge rates minimize board induced jitter.

Exact frequency multiplying ratios ensure better than ±80

ppm frequency accuracy using a standard AT crystal with

external load capacitors (typically 33pF ±5% for an 18pF

series load crystal).

Achieving ±80ppm over four years

requires the crystal to have 20 ppm initial accuracy, ±20 ppm

temperature and ±5 ppm/year aging coefficients.

Block Diagram

PRODUCT PREVIEW documents contain information on products in the formative or

design phase development. Charactersitic data and other specifications are design

goals. ICS reserves the right to change or discontinue these procucts without notice.