Electronics Production | December 17, 2004
PREMIS Spread Spectrum Clock Oscillator
Cypress Semiconductor Corp. announced volume production of its CY25701 programmable Spread Spectrum Crystal Oscillator (SSXO) with a high-frequency reference crystal in a single package.
The onboard crystal has been specified, designed, and tested to operate with Cypress’s feature-rich, programmable Peak Reducing EMI Solutions (PREMIS™) Spread Spectrum chip which significantly reduces design and test time, and product development cost as compared to an external crystal solution. By integrating frequency synthesis and Spread Spectrum clock functions into the device, the CY25701 runs efficiently with the onboard crystal. By using this device, designers can eliminate difficult-to-use, higher-order crystals or crystal oscillators—saving them time, money and board space. In addition, the frequency programmability of the SSXO enables designers to set a wide range of spread percentages for maximum electromagnetic interference (EMI) reduction. “Considering that there are over 10,000 crystal types in the marketplace worldwide, it’s a huge undertaking to match a crystal to any given clock generator,” said Cavit Ozdalga, product marketing manager for Cypress's Timing Technology Division. “The CY25701 eliminates repeated customer design and test cycles by providing reliable operation between the reference crystal and the Spread Spectrum clock generator.” The CY25701 SSXO offers a wide, programmable operating output frequency range, enabling designers to program the clock frequency from 10 to 166 MHz. In order to meet regulatory agency electromagnetic compliance requirements, the programmable Spread Spectrum feature provides a wide range of down- or center-spread percentages (0.5 to 4.0%) for maximum EMI reduction. Depending on the application, the CY25701 provides up to 20 dB EMI reduction, based on a worst-case harmonic. The CY25701 is an extension of Cypress's current line of programmable EMI reduction clocks including the highly successful multiple-output CY25100 and CY25200 which, unlike the CY25701, require an external crystal. A non-spread, pin-compatible version of the CY25701 will be available in late Q404. The CY25702 enables customers to design in a crystal oscillator with protection in their back pocket. If they should fail EMI testing, the problem can be resolved by simply dropping in the spread spectrum version, CY25701. This ensures flexibility in design, whatever the customers' needs may be.