Precision offers spread-spectrum clock oscillators

Precision Devices has introduced two spread-spectrum clock oscillators.

The SSOC5 and the SSOC7 are intended to provide an efficient and economic method of reducing system EMI at its source: the clock oscillator.

The modulated output frequency of the SSOC5 and the SSOC7 enables EMI to be reduced by up to 15dBc relative to fixed crystal oscillators.

The SSOC5 and the SSOC7 operate with a 3.3V supply voltage and the CMOS clock generator produces a square-wave fixed-output frequency range from 6.00MHz to 160.00MHz and 3.6MHz to 220.00MHz respectively.

A spread-spectrum crystal clock oscillator is an oscillator that has the output frequency modulated in order to reduce EMI on the output signal.

Frequency sources such as quartz crystal oscillators, phase-lock-loop (PLL) synthesisers and other types of clock signal generation are a major source of EMI in electronic circuits, according to the company.

The use of a spread-spectrum clock oscillator at the design and development stage will negate the need for expensive EMI reduction techniques such as filtering components and shielding enclosures and multiple ground and power planes.

Advantages of using low-EMI spread-spectrum oscillators are: simplified regulatory testing; a shorter time to market; and reduced system costs.

Precision Devices specifies a load termination of 15pF maximum, with rise and fall times of 4.0ns maximum (10 per cent to 90 per cent of the waveform).

The SSCO5 and the SSCO7 offer +/-25ppm, +/-50ppm and +/-100ppm frequency stability options over an operating temperature range of 0C to +70C with a -40C to +85C option available.

The SSCOC5 is available in a four-pin SMD package with dimensions of 5.0mm x 3.2mm x 1.2mm, while the SSOC7 is available in a four-pin SMD package with dimensions of 7.0mm x 5.0mm x 1.8mm.

Typical applications include office equipment, computer systems, telecommunications, set-top boxes and embedded systems.

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