3HM57 Group “R”
A DROP-IN REPLACEMENT SOLUTION FOR YOUR
EMI / EMC COMPLIANCE PROBLEM
The principle sources of the EMI problem
come from the system clocks. Therefore, rather
than patch the problem with ferrite beads, EMI
filters, ground plane and metal shielding, the most
efficient and economic way to reduce the peak
radiation energy is to use the low EMI clock
oscillator.
Compared with the conventional clock
oscillators, Mercury HM57 series spread spectrum
(dithered) clock oscillators can reduce EMI as
much as 12 dB. The beauty is it is a drop-in
replacement for your existing 5x7 clock oscillator.
No need to re-spin the board.
3HM57 reduces your EMI
and shorten your time to market.
Applications
◘
Printers; Multiple function printers (MPCs)
◘
Digital copiers; PDAs
◘
Networking; LAN / WAN; Routers
◘
Storage systems
(CD-ROM,
VCD, DVD and HDD)
◘
Scanner; Modems; projectors
◘
Hand-held ID readers
Modulation Types
◘
Embedded systems; Electrical musical instrument
◘
Automotive; GPS car navigation systems
◘
LCD PC monitors / LCD TVs
◘
ADSL; PCMCIA
◘
Still Digital cameras (SDCs)
Output amplitude (dB) vs frequency span (MHz)
Center spread “C”.
“C0.5” as an example
Conventional
Clock
EMI reduction
Down spread “D”.
“D1” as an example
Conventional
Clock
EMI reduction
Spread
spectrum
clock
dB
fo - (fo*1%)
fc
Frequency
fo - (fo*0.5%)
fo=fc
fo + (fo*0.5%)
Spread Spectrum Clock (SSC):
Unlike the conventional clock, the
mode energy of a spread spectrum
clock is spread over a wider
bandwidth, resulting from the
frequency modulation
technique. The
modulation carrier frequency is in the
KHz range which makes the
modulation process transparent to the
oscillator frequency. The controlled
modulation process can be on all of
one side of the nominal frequency
(down
spread)
or 50% up and 50%
down (center
spread).
The down
spread is preferred if
over-clocking
is
a problem to the system.
Taiwan: TEL (886)-2-2406-2779, FAX (886)-2-2496-0769, e-mail:
sales-tw@mercury-crystal.com
U.S.A.: TEL (1)-909-466-0427, FAX (1)-909-466-0762, e-mail:
sales-us@mercury-crystal.com
Page 1 of 5
April. 19. 2005 Rev. G
MERCURY
www.mercury-crystal.com
MERCURY [ MERCURY UNITED ELECTRONICS INC ]
