EQHM42 Group ‘R’ Low EMI Oscillators
11.4 x 9.6 x 2.5mm SMD Spread Spectrum Clock Ocillator
Provides up to 12dB reduction in system EMI
‘Drop-in’ replacement for standard clocks
Choice of modulation rate and spread
SMD package: 11.4 mm x 9.6 mm x 4.7mm
Page 1 of 3
DESCRIPTION
The principal cause of EMI problems is the system
clock. Therefore, rather than patch the problem
with ferrite beads, filters, ground planes and
metal shielding the most efficient and economic
method of EMI reduction is to use a low EMI clock
oscillator.
Compared with conventional clock oscillators
3EQHM44R series Spread Spectrum (Dithered)
Oscillators can reduce RMI by as much as 12dB.
The part is a 'drop-in' replacement for a standard
11.4 x 9.6mm SMD clock oscillator hence there is
no requirement to re-design existing PCBs.
EQHM42R series low EMI oscillators can reduce system EMI by 12dB.
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 in the kHz region makes the process
transparent to the oscillator frequency. There is a choice of
modulation rates and spread.
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 resulting from the frequency modulation technique. The
controlled modulation process may be on all on one side of the
nominal frequency (known as
DOWN SPREAD,)
or spread equally
either side of nominal (CENTRE
SPREAD).
Down Spread is preferred
is over-clocking would be 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
EQHM42 Group ‘R’ Low EMI Oscillators
11.4 x 9.6 x 2.5mm SMD Spread Spectrum Clock Ocillator
Page 2 of 3
SPECIFICATION
Model No:
Frequency Range:
Spread Types:
EMI Reduction*:
Modulation Carrier Frequency:
3EQHM42 (Group ‘R’)
5.0MHz to 160.0MHz
See table below
-9dBc min. 100MHz at C0.5**
-15dBc min. 100MHz at C1.5**
6.9kHz min, 55.5kHz max.
Frequency dependant
CMOS
Vdd = +3.3VDC ±5%
OUTLINE & DIMENSIONS
Output Logic:
Input Voltage:
Frequency Stability***
Commercial (0~70°C):
±25ppm (Spec. code = ‘A’)
±50ppm (Spec. code = ‘B’)
±100ppm (Spec. code = ‘C’)
Industrial (-40~+85°C):
±25ppm (Spec. code = ‘D’)
±50ppm (Spec. code = ‘E’)
±100ppm (Spec. code = ‘F’)
Output Voltage HIGH ‘1’:
2.0V min., 3.2V typ. (90%Vdd)
Output Voltage LOW ‘0’:
0.8V min., 0.2V typ. (10%Vdd)
Load:
15pF
Start-up Time:
2ms typical, 5ms max.
Current Consumption:
10MHz: 7mA, 32.768MHz: 8mA
75MHz: 17mA, 125MHz: 18mA
Duty Cycle:
50%±5% (CL=15pF, 50&Vdd)
Cyle to Cycle Jitter:
±250ps typ. ±300ps max.
Output Impedance:
40 Ohms
Static Discharge Voltage:
>2000V (per MIL STD 833)
Storage Temperature:
-65°C to +150°C
Ageing:
±5ppm /year max at Ta=25°C
Packaging:
EIA 16mm tape and reel, 1k per.
Pad 1:
Output Enable/Disable. Tristate
output when LOW. 100kOhm
internal pull-up resistor.
Output enable time 100ns max.
Notes:
*
EMI reduction is applied to the entire frequency
** dBc: with respect to no modulation. Frequency and total %
spread dependant. Call Euroquartz technical sales for detail.
*** Frequency Stability parameters excludes modulation.
PART NUMBER CONFIGURATION
AVAILABILITY OF SPREAD TYPES AND MODULATION RATES
‘T’ Tristate
Group ‘R’
SPREAD TYPES and % MODULATION
DOWN SPREAD
3EQHM42-BT-32.768R-C0.5
Frequency (MHz)
Frequency Stability Code
‘A’ to ‘F’. See specification above
D1.0
D3.0
CENTRE SPREAD
C0.5
C1.5
-1%
-3%
±0.5%
±1.5%
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
stm32/stm8
京公网安备 11010802033920号
EEWORLD
