IMISG509 Datasheet, PDF (1/7 Pages) –

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IMISG509
REDUCED EMI CLOCK CHIP
April 1996
PRODUCT FEATURES
þ Generates CPU clock signals for microprocessor
systems
þ Reduces measured EMI by 10 dB nominal
þ 4V to 6V operating supply range
þ Supports CPUs from all major manufacturers.
þ Wide range of selectable output frequencies
including 60, 50, 48, 40, 33.3, 16.7
þ Single, low-cost crystal used as reference
frequency
þ Glitch-free switching
þ 50% duty cycle
þ TTL or CMOS compatible outputs with 6 mA drive
capability
þ Low, short and long-term jitter
þ 16 pin P-DIP and 16 Pin SOIC (300 mil body)
package options
BLOCK DIAGRAM
3
44.2 MHz
2
REF
MPSEL ⁵
10
LF
7
S0
8
S1
S3 ¹⁶
SSON
9
SPECTRUM
SPREAD
CLOCK GEN
/4 OR /12 ¹⁴ MPCLK
/2
12 _PRCLK
CMOS LSI
SPECTRUM SPREAD CLOCK GENERATOR
PRODUCT DESCRIPTION
The IMISG509 is a spectrum spread clock generator
specially designed for personal computers, laser
printers and other digital systems. IMISG509 uses a
patented concept to generate popular clock frequencies
that are intentionally broadbanded to reduce
electromagnetic interference. The radiated emissions,
associated with either the clock, harmonics or any
signals derived from the clock, nominally reduced by
10 dB and could significantly reduce the cost of
complying with the regulatory requirements.
PRCLK is the broadbanded output and can be
programmed by the PRCLK Frequency Selection Table
on Page 2. A single, low cost external crystal is
required as reference frequency for the synthesizer.
The output modulation function can be disabled when
the SSON pin is high.
CONNECTION DIAGRAM
VDD 1
OSCin 2
OSCout 3
VSS 4
MPSEL 5
AVDD 6
S0 7
S1 8
16 S3
15 VDD
14 MPCLK
13 VSS
12 PRCLK
11 AVSS
10 LF1
9 SSON
APPLICATIONS
IMISG509 eliminates the need for multiple oscillators
and generates the CPU clock signals for personal
computers, laser printers and other digital systems.
Supports CPUs from all major manufacturers.
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL: [phone] FAX [phone]
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