ICS9117-01 Datasheet, PDF (1/5 Pages) Integrated Circuit Systems – Frequency Generator for Modem Systems

Integrated
Circuit
Systems, Inc.
ICS9117-01
Frequency Generator for Modem Systems
General Description
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.
Features
• 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
Block Diagram
14.7456
MHz
X2
XTAL
X1 ^OSC
÷8
PLL
PD
CLOCK
GEN
PCLK
UCLK
MCLK
9117-01 RevA 052297P
Pentium is a trademark of Intel Corporation
PowerPC is a trademark of Motorola Corporation
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design phase development. Charactersitic data and other specifications are design
goals. ICS reserves the right to change or discontinue these procucts without notice.