Cosmic Circuits expands PLL range

by K C Krishnadas, TechOnline India - August 24, 2011

Cosmic Circuits has expanded its PLL offering to include the advanced deep-submicron process nodes as well as support a number of different requirements.

Cosmic Circuits has expanded its PLL offering to include the advanced deep-submicron process nodes

as well as support a number of different requirements. The PLL solutions are now available in every process node from 180nm to 28nm. The different applications supported include ultra-flexible system-clocking generation, spread-spectrum modulation, high-speed SERDES such as SATA and MIPI M-PHY, communication systems such as WiFi and long-term evolution (LTE), broadcast and audio.

Cosmic provides multiple variants of its system-clocking PLLs with the CC0520INPLLxx family of ultra-low-area PLLs that utilizes both the core and IO supplies and the CC0P032INPLLxx family of ultra low-power PLLs that operate from a single supply. The PLLs do not use any external components and can accept reference frequencies as low as 32kHz. Cosmic Circuits also provides spread-spectrum PLLs such as CC0520SSPLLxx that mitigate electro-magnetic interference (EMI) by spreading out the energy of the narrow-band clock signal into a wider bandwidth. Cosmic Circuits system-clocking

and spread-spectrum PLLs are available in a number of process technologies and have been integrated in some of the leading portable media players.

Applications such as high-speed SERDES and LTE are very sensitive to the long-term accumulated jitter
of the PLL. Large accumulated jitter in the PLL will degrade the eye-opening, resulting in poor bit-error rate for the high-speed SERDES. Communication applications such as LTE operate on sinusoidal signals, and errors in the timing instants increase the total noise, hampering system performance. A PLL such as the CC4016INPLL that achieves <5ps of long-term accumulated jitter would be an ideal fit for these applications.

WiFi is now an integral part of a number of different products and it is becoming increasingly important
that the PLL used for WiFi be capable of working with a wide range of crystal frequencies. To remove any constraints on crystal frequency, it is desirable to provide the user complete freedom in setting the input frequency of the PLL. Such an approach is possible only if a fractional-N PLL is used in the analog
front-end. Cosmic Circuits provides these fractional-N PLLs that achieve the stringent jitter specifications that WiFi systems impose while offering the user flexibility in choosing the PLL's reference frequency. These PLLs operate from the core supply, resulting in very low power dissipation.

Cosmic Circuits is one of the few IP vendors that provide a detailed characterization report for its PLL solutions. In addition to PLLs, Cosmic also provides crystal oscillators and crystal-replacement silicon oscillators. The silicon oscillators achieve < 2% accuracy over PVT and are used today in different types of controllers (memory controllers, microcontrollers, controllers in connectivity applications).

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