SG536
Low EMI Clock Generator for Multi-Function Products
Approved Product
PRODUCT FEATURES
CONNECTION DIAGRAM
VDD
XIN
XOUT
VSS
CPUsel1
T
Supports clocking requirements for Multi-
T
T
T
T
T
Integrates a Spectrum Spread
Function Products supporting Printers,
Copiers, Scanners, Fax/modem integration.
Programmable CPU clock output.
Operates from 3.3V or 5V supply
60 mA buffer switching current
16 Pin SOIC for minimum board space
technology for EMI attenuation of up to
15dB at harmonic frequencies.
The IMISG536 is a clock generator that integrates
clocking requirements for Multi-Function Products
or stand alone products such as Printers, Copiers,
and Scanners.
In addition, it integrates a
Spectrum Spread technology , a modulation
technique designed specifically for reducing EMI
at the fundamental frequency and at its
harmonics. The EMI attenuation is proportional to
the frequency, therefore achieving greater
reduction at the harmonics where it is more
difficult to pass federal regulations for radiated
emissions (such as FCC, CSPIR, etc.).
The IMISG536 operates from a 20 MHz
crystal oscillator across pins 2 and 3, or from an
external clock source. The REF output is a
buffered output of the input signal at XIN. CPUclk
is the modulated output for EMI attenuation. This
clock has optional frequency outputs which can
be selected with CPUsel(0:1).
VIDclk (60 MHz) and SCNclk(40 MHz) are highly
accurate fixed frequencies and therefore are not
modulated.
This device is packaged in a 16 pin SOIC
package for minimum occupation of board space.
CPUsel0
VSS
VDD
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
REF
CPUclk
VSS
VDD
SCNclk
VIDclk
VSS
MODsel
CPUclk SELECTION TABLE
CPUsel1
0
0
1
1
CPUsel0
0
1
0
1
CPUclk (MHz)
16
33
25
50
BLOCK DIAGRAM
20 MHz
XIN
REF
XOUT
B
REF
CPUsel1
CPUsel0
MODsel
PLL1
SSCG
Control
B
CPUclk
PLL2
B
B
VIDclk
SCNclk
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035. TEL: 408-263-6300. FAX 408-263-6571
Rev.1.1
6/26/97
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