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| 3EQHM57 Group `P' Low EMI Oscillators 7 x 5 x 1.8mm SMD Spread Spectrum Ocillator, Low Jitter Provides up to 15dB reduction in system EMI `Drop-in' replacement for standard clocks Choice of modulation rate and spread Miniature package: 7.0mm x 5.0mm x 1.8mm Page 1 of 2 In electrical systems the principal cause of electromagnetic 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 EQHM57 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 overclocking 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 3EQHM57 Group `P' Low EMI Oscillators 7 x 5 x 1.8mm SMD Spread Spectrum Ocillator, Low Jitter Page 2 of 2 SPECIFICATION Model No: 3EQHM57 (Group `P') Frequency Range: 13.0MHz to 220MHz Spread Types: See table below EMI Reduction*: EMI Reduction (dB) = 10log("Total%"x"SSC Frequency(MHz)"/0.12) Modulation Carrier Frequency: 25.3kHz min, 58.6kHz max. Frequency dependent Call for details Output Logic: CMOS Input Voltage: Vdd = +3.3VDC 5% Frequency Stability*** Commercial (0~70C): 25ppm (Spec. code = `A') 50ppm (Spec. code = `B') 100ppm (Spec. code = `C') Industrial (-40~+85C): 25ppm (Spec. code = `D') 50ppm (Spec. code = `E') 100ppm (Spec. code = `F') Output Voltage HIGH `1': 2.4V min. at 80% Vdd Output Voltage LOW `0': 0.4V max. at 20% Vdd Rise/fall Times: 1.2ns max, (frequency dependant) Load: 15pF Start-up Time: 2ms typical, 5ms max. Current Consumption: 25mA typical, freq. dependant Duty Cycle: 50%5% (CL=15pF, 50%Vdd) Cycle to Cycle Jitter: 100ps typ. 150ps max. Output Impedance: 40 Ohms typical Static Discharge Voltage: >2000V (per MIL STD 833) Storage Temperature: -65C to +150C Ageing: 5ppm /year max at Ta=25C Packaging: EIA 16mm tape and reel, 1k per. Pad 1 Option: No function available. Do not electrically connect pad 1. 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. OUTLINE & DIMENSIONS ENVIRONMENTAL SPECIFICATION RoHS Compliance: Storage Temperature Range: Humidity: Hermetic Seal: Solderability: Reflow: Vibration: Shock: RoHS compliant and Pb (lead) free -55 to +125C 85% RH, 85C for 48 hours Leak Rate 2x10-8 ATM-cm3/s max. MIL-STD-2002F method 208E 260 for 10 seconds MIL-STD-202F method 204, 35g 50Hz to 2000Hz MIL-STD-202F method 213B, test condition: E, 1000g 1/2 sine wave SPREAD TYPES and % MODULATION PART NUMBER CONFIGURATION DOWN SPREAD Series designation Group `P' D0.5 D0.75 -0.5% -0.75% -1.25% -2.0% -2.5% -3.0% -3.5% -3.75% CENTRE SPREAD C0.25 C0.375 C0.625 C1.0 C1.25 C1.5 C1.75 C1.875 0.25% 0.375% 0.625% 1.0% 1.25% 1.5% 1.75% 1.875% 3EQHM57-B-32.768P-C0.5 Frequency (MHz) Frequency Stability Code `A' to `F'. See specification above D1.25 D2.0 D2.5 D3.0 D3.5 D3.75 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 |
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