EQHM8 Group ‘R’ Low EMI Oscillators
8 pin Dual-in-Line Spread Spectrum Clock Ocillator
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
Page 1 of 2
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.
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.
DESCRIPTION
EQHM8 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.
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
EQHM8 Group ‘R’ Low EMI Oscillators
8 pin Dual-in-Line Spread Spectrum Clock Ocillator
Page 2 of 2
SPECIFICATION
Model No:
Frequency Range:
Spread Types:
EMI Reduction*:
3EQHM14 (Group ‘R’)
3.5MHz to 165.0MHz
See table below
-7dBc min. 100MHz at C0.25**
-9dBc min. 100MHz at C0.5**
-15dBc min. 100MHz at C1.5**
With reference to dB level at no
modulation.
6.9kHz min, 55.5kHz max.
Frequency dependent
Call for details
CMOS
Vdd = +3.3VDC ±5%
±25ppm (Spec. code = ‘A’)
±50ppm (Spec. code = ‘B’)
±100ppm (Spec. code = ‘C’)
±25ppm (Spec. code = ‘D’)
±50ppm (Spec. code = ‘E’)
±100ppm (Spec. code = ‘F’)
2.0V min., 3.2V typ. (90%Vdd)
0.8V max., 0.2V typ. (10%Vdd)
4ns max, (frequency dependant)
15pF
2ms typical, 5ms max.
-65° to +150°C
10mA typical
18mA typical
50%±5% (CL=15pF, 50%Vdd)
±250ps typ. ±300ps max.
40 Ohms typical
>2000V (per MIL STD 833)
±5ppm /year max at Ta=25°C
EIA 16mm tape and reel, 1k per.
Output Enable/Disable. Output is
high impedance when taken low
Output enable time 100ms max.
OUTLINE & DIMENSIONS
Modulation Carrier Frequency:
Output Logic:
Input Voltage:
Frequency Stability***
Commercial (0~70°C):
Industrial (-40~+85°C):
Output Voltage HIGH ‘1’:
Output Voltage LOW ‘0’:
Rise/fall Times:
Load:
Start-up Time:
Storage Temperature:
Current Consumption:
10 ~ 50MHz:
50 ~ 125MHz:
Duty Cycle:
Cycle to Cycle Jitter:
Output Impedance:
Static Discharge Voltage:
Ageing:
Packaging:
Pad 1 Option:
Notes:
*
EMI reduction is applied to the entire frequency spectrum
** dBc: with respect to no modulation. Frequency and total %
spread dependant.
*** Frequency Stability parameter excludes modulation.
PART NUMBER CONFIGURATION
‘T’ for Tristate option; Blank if Tristate not required
Group ‘R’
AVAILABILITY OF SPREAD TYPES AND MODULATION RATES
SPREAD TYPES and % MODULATION
3EQHM8-BT-32.768R-C0.5
3EQHM18 for SMD version
Frequency (MHz)
Frequency Stability Code
‘A’ to ‘F’. See specification above
DOWN SPREAD
D1.0
D3.0
CENTRE SPREAD
C0.5
C1.5
±0.5%
±1.5%
-1%
-3%
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
Analog electronics
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