Ultralow jitter OTN clock translator in minimal footprint

November 24, 2014 // By Graham Prophet
Microsemi’s ZL30169 high performance, ultrasmall form factor clock translator supports the deployment of 100G coherent optical networks

ZL30169 high performance Optical Transport Network (OTN) clock translators are fully compliant with the ITU-T G.8251 standard that ensures interoperability and network performance. The ultrasmall, three-input, three-output any-rate-to-any-port clock translator for OTN provides output clocks with jitter performance of 250 fsec RMS, for 100G coherent optical networks.

The ZL30169 integrates a digital phase locked loop (DPLL), analogue PLL (APLL) and EEPROM into a 5 x 5 mm 32-pin QFN package. The APLL generates the ultralow jitter output clocks programmable to any frequency from 1 Hz to 1035 MHz, the first device of its kind offering such a wide range. With programmable loop bandwidth from 14 Hz to 500 Hz, the DPLL accepts any input frequency from 1 kHz to 1250 MHz and provides hitless reference switching, holdover and jitter filtering. The EEPROM provides automatic self-configuration of the device at start-up. The ZL30169 has features such as dynamic rate conversion for forward error correction used in OTN transport and switching applications. The ZL30169 meets all the jitter and wander requirements that are specified in the ITU-T G.8251 Recommendation to ensure satisfactory network performance.

The ZL30169 also offers Numerically Controlled Oscillator (NCO) mode in which output frequencies can be controlled with very high resolution (better than 0.01 ppb) by system software. This capability provides a cost-effective solution for customers designing their own Mapper with FPGAs to replace large, expensive, fixed-frequency voltage-controlled oscillators (VCXOs).

100 Gb/s is likely to be the next speed, in 2015 to 2030, with greater than $10 billion in revenue expected by 2018, mostly from service providers – according to industry analysts. In 2013, the number of 100G ports shipped grew five-fold to 70,000. 100G coherent technology enables transport of 100G data rate across long distances, up to 2500 km.

“100G coherent technology is being rapidly adopted by carriers because of its spectral efficiency and reach. This triggers the need to support more flexible client rates with stringent jitter