3EQHM53 Group ‘Y’ Low EMI Oscillators
5 x 3.2 x 1.2mm SMD Spread Spectrum Clock Ocillator
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Provides up to 15dB reduction in system EMI
‘Drop-in’ replacement for standard clocks
Choice of modulation rate and spread
Miniature package: 5.0 mm x 3.2 mm x 1.2mm
In electrical systems the principal cause of electro-
magnetic interference (EMI) is the system clock
oscillator. Traditional methods of 'patching-up' systems
with too high a level of EMI is to use ferrite beads,
filters, ground planes, metal shielding and similar costly
methods, However, the most efficient and economic
method to reduce EMI is to reduce it at source: replace
the system clock ocillator with a low EMI clock oscillator.
DESCRIPTION
EQHM53 series low EMI oscillators can reduce system EMI by 15dB.
The oscillators are a ‘drop-in’ replacement for standard oscillators.
EMI reduction is achieved by the use of Spread Spectrum Technology
whereby the mode energy is spread over a wider bandwidth. The
modulation carrier frequency, operating in the kHz region, makes the
process transparent to the oscillator frequency. There is a choice of
modulation rates and spread to suit application requirements.
Compared with conventional clock oscillators, Spread
Spectrum (Dithered) Oscillators can reduce EMI by as
much as 15dB. The part is a 'drop-in' replacement for a
standard clock oscillator hence there is no requirement
to re-design existing PCBs.
SPREAD SPECTRUM TECHNOLOGY
Unlike a conventional clock oscillator, in a Spread Spectrum Clock
Oscillator the mode energy is spread over a wider bandwidth. This is
achieved by the frequency modulation technique. The controlled
modulation process may be applied to the 'down' side of the nominal
frequency (known as DOWN SPREAD,) or spread equally either side
of nominal (CENTRE SPREAD). Down Spread is preferred if over-
clocking would cause a problem to the system.
APPLICATIONS
Printers, Multiple Function Printers (MPCs)
Digital Copiers; PDAs
Networking: LAN/WAN; Routers
Storage Systems (CD-ROM, VCD, DVD, HDD)
Scanners; Modems; Projectors
Embedded Systems
Musical Instruments
Automotive: GPS car navigation systems
LCD PC Monitors; LSD TVs
ADSL; PCMCIA
Still Digital Cameras (SDCs)
MODULATION TYPES - EXAMPLES
Output amplitude (dB) vs. frequency span (MHz)
EUROQUARTZ LIMITED Blacknell Lane CREWKERNE Somerset UK TA18 7HE
Tel: +44 (0)1460 230000 Fax: +44 (0)1460 230001 info@euroquartz.co.uk www.euroquartz.co.uk
EUROQUARTZ [ EUROQUARTZ LIMITED ]
