Programmable frequency translator outputs up to 8 different frequencies with less than 0.3ps jitter

Programmable frequency translator outputs up to 8 different frequencies with less than 0.3ps jitter

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By eeNews Europe

The mixed signal devices offers eight independently-programmable clocking outputs with the flexibility to apply virtually any input frequency and select virtually any output frequency.

The 8T49N28x devices are available with one or two PLLs in a single package, depending on the needs of the application. When configured as a frequency synthesizer, the device can use a low-cost, readily-available 10 to 40MHz crystal to produce any frequency from 8kHz to 1.0GHz, regardless of the crystal frequency used. In a frequency translator configuration, the devices accept up to four input reference clocks per PLL from 8 kHz to 875 MHz, switching between them as necessary to generate any output frequency from 8 kHz to 1.0 GHz. These multiple inputs can also be used for redundancy purposes. Each output is individually programmable as LVPECL, LVDS, or as a pair of LVCMOS signals.

What’s more, the chip’s integrated fractional output divider has been improved through architectural changes in the analogue domain to be able to generate independent clock frequencies with less than 0.7ps of RMS jitter.

IDT is also a provider of MEMS-based oscillators supporting 100 femtosecond (0.1ps) typical phase jitter performance, so in the future the company could deliver System-in-Package solutions combining the clock sources and the frequency translators.

“A combined solution is definitely on our road map and it would certainly bring a cost advantage”, said Director of System Architecture, Ian Dobson, “though most of our customers in the telecoms market are fairly conservative and are not ready to adopt our MEMS-based technology, they would rather combine our frequency synthesizer chips with external crystal oscillators, a proven technology that has been around for 75 years or so.” “Whatever the roadmap, we’ll leave the option of designing with crystal oscillators open”.

For engineers to fully exploit the flexibility of the devices, the company makes available its Timing Commander software. The tool offers a complete view of the device’s internals, with easy to fill blanks to choose your input and output frequencies, with contextual menus and design help at hand. Designers can then view the phase noise plot for the output frequencies for which they have configured the device and compare one configuration with another for optimum performance. Still in the making, a future option of the tool will offer filtering circuit advice and simulation capabilities.

The IDT 8T49N281i, 8T49N282i , 8T49N283i and  are currently sampling to qualified customers. The 8T49N281i and 8T49N 283i are available in a 56-lead 8x8mm VFQFPN package, and the 8T49N282i is available in a 72-lead 10x10mm VFQFPN package.

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