Spread spectrum oscillator is drop in replacement with reduced EMI
Offering customers a drop-in replacement for standard clock oscillators with a reduction in EMI by as much as 12dB, the EQHM22 spread spectrum oscillator has been introduced by Euroquartz.
In electronic systems, a principal cause of EMI is the system clock oscillator and traditional methods of combatting interference, such as ferrite beads, ground planes and metal shielding, are frequently costly and awkward to implement, said Euroquartz. They are also typically applied after a system has failed EMI testing.
The most efficient method to reduce EMI is to suppress it at source, advised Euroquartz. Compared with conventional clock oscillators, spread spectrum (dithered) oscillators can reduce EMI by up to 12dB and the parts are drop-in replacements for standard components so there is no requirement to redesign existing PCBs.
The EQHM22 series offers a choice of modulation rates and spreads in frequencies from 16 to 40MHz in a miniature surface mount package measuring 2.5 x 2.0 x 0.9mm. Frequency stability is available as low as ±25ppm in both commercial (0 to 70 degrees C) and industrial (-40 to +85 degrees C) grades. Input voltages of 1.8, 2.5 and 3.3V DC are available, all ±10%. Output logic is CMOS with load capability of 15pF.
The current consumption is 4.0, 5.0 or 6mA depending on voltage model and the oscillators have rise/fall times from 7ns to 10ns. Start up time is one millisecond (typical), five milliseconds maximum. The oscillators also have output enable/disable function and duty cycle of 50 per cent ±10 per cent. Ageing is ±5ppm/year maximum at 25 degrees C ambient temperature.
The EQHM22C low EMI oscillators are suitable for use in a wide range of applications including printers and multifunction printers, digital copiers, PDAs, networking LAN/WAN and routers, storage systems such as CD-ROM, DVD and HDD, scanners, modems, projectors, embedded systems, automotive GPS navigation systems, LCD PC monitors and TVs, ADSL, PCMCIA devices and digital cameras.
They are supplied in EIA 16mm tape and reel packaging for volume production requirements.
Euroquartz is an independent UK-based manufacturer and supplier of quartz crystals, oscillators, filters and frequency-related products to the electronics manufacturing industry worldwide. The company is AS9100 registered and designs and manufactures a comprehensive range of frequency control components for a wide range of customers including major OEMs covering a broad spectrum of applications including defence and aerospace, communications, general electronics, computing, control systems and petrochemical among many others.
