Drop-in oscillator simplifies bills- of-materials

Euroquartz’ new drop-in spread spectrum oscillator can help original equipment manufacturers pass EMI tests without adding extra shielding or redesigning circuits

Euroquartz is launching a new spread spectrum oscillator offering customers a drop-in replacement for standard clock oscillators with a reduction in electromagnetic interference (EMI) by as much as 12dB.

In electronic systems a principal cause of EMI is the system clock oscillator. Traditional patching-up methods of combatting interference—ferrite beads, ground planes, metal shielding and similar—are frequently costly, awkward to implement and often applied after a system has failed EMI testing.

The most efficient method to reduce EMI is suppression at source, something Euroquartz’ new EQHM22 is designed to do. Compared with conventional clock oscillators, spread spectrum (dithered) oscillators can reduce EMI by up to 12dB. The parts are drop-in replacements for standard components, eliminating PCB redesign.

Offering a choice of modulation rates and spreads, these devices offer frequencies from 16 to 40MHz in a miniature surface mount package measuring 2.5 by 2.0 by 0.9mm. Frequency stability is available as low as ±25ppm in both commercial (0 to 70°C) and industrial (-40 to +85°C) grades with input voltages of 1.8, 2.5 and 3.3VDC available, all ±10 per cent. Output logic is CMOS with load capability of 15pF.

Additional specifications include: current consumption of 4, 5 or 6mA depending on voltage model; rise/fall times from 7ns to 10ns; start up time of 1ms typical, 5ms maximum; output enable/disable function; and duty cycle of 50% ±10%. Ageing is ±5ppm/ year maximum at 25°C ambient temperature.

Applications include 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/TVs, ADSL, PCMCIA devices and digital cameras.

The oscillators are supplied in EIA 16mm tape and reel packaging for volume production.