Device generates & distributes low jitter signals

22nd January 2015

Nat Bowers

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Datasheet

Generating and distributing the low jitter signals essential to clocking data converters with a high SNR, Linear has announced a low phase noise integer-N synthesiser core with an ultralow jitter clock distribution output section. The LTC6950 integrates a PLL which offers a normalised in-band phase noise floor of -226dBc/Hz and exceptionally low -274dBc/Hz normalised 1/f phase noise which stays intact going through the clock distribution section.

These specifications ensure designers take full advantage of the good phase noise performance of the external oscillator that is being locked by the LTC6950 and deliver the best jitter performance in this class of parts.

Maintaining low jitter on the data converter clock is fundamental to achieving outstanding SNR levels when digitising or synthesising high analogue frequencies. For instance, modern electronic systems demand direct digitisation of RF and high IF signals using an ADC. With 18fsRMS jitter (over the 12kHz to 20MHz bandwidth), the LTC6950 guarantees the best performance out of such a system.

The LTC6950 incorporates Linear’s proprietary EZSync output synchronisation, a simple, effective method to edge-synchronise multiple outputs from either one chip or multiple chips. EZSync synchronisation aligns the rising edges by simply asserting a common CMOS input with loose timing requirements. EZSync can also be used to produce repeatable and deterministic phase relationships between the clock divider outputs of devices that have this feature enabled.

To simplify the design process of the LTC6950, the ClockWizard free simulation and design tool can be downloaded from the company's website. The ClockWizard GUI helps find loop filter component values with a click of a button and accurately predicts the individual output’s phase noise and jitter, helping the designer make the correct choices during the design and debug phases.

Operating over a temperature range from -40 to +105°C, the LTC6950 is available in a 5x9mm, 48-lead plastic QFN package. It is priced at $9.95 in 1,000 unit quantities and is available immediately from stock.