Low jitter for drop-in PLL synthesiser replacement

The NBC12429FN is a 3.3/5.0V programmable PLL clock synthesiser that provides a 25 to 400MHz system clock ideal for the primary timing signals in networking, telecomms and test hardware.

The NBC12429FN is a 3.3/5.0V programmable phase locked loop (PLL) clock synthesiser that provides a 25 to 400MHz system clock ideal for the primary timing signals in networking, telecomms and test hardware.

This device is the first in a family of six PLL clock synthesisers that ON Semiconductor plans to introduce within the next month.

Each of the devices to be introduced will be a drop-in replacement for devices being discontinued by Motorola.

"The ON Semiconductor family of clock synthesisers eliminates the need for expensive redesigns of customer applications or massive orders meant to cover the life of the project", said Bill Schromm, ON Semiconductor Vice President for Clock and Data Management Products.

The NBC12429FN uses an external oscillator to provide a reference signal that is then synthesised to produce the final clock.

Using a 16MHz external crystal oscillator with the NBC12429FN, for example, accommodates output clock signals in the range of 25 to 400MHz in 1MHz steps - a highly flexible level of programmability.

An internally integrated PLL provides programmable bandwidth to balance jitter filtration and lock time with only minimal frequency overshoot.

Based on the proven Mosaic-5 process technology, the NBC12429FN offers best-in-class jitter at +/-20ps peak-peak.

The device operates on both 3.3 and 5V voltage supplies, providing design flexibility in the end application.

A parallel and a serial interface are used to program the device, providing a reliable startup state.

The remaining five devices will be available by April.

They are: the NBC12429FA, which is identical to the NBC12429FN, but in a 32-pin LQFP; the NBC12430FN, a 3.3/5V programmable PLL synthesised clock generator (50 to 800MHz) in a 28-pin PLCC package; the NBC12430FA 3.3/5V programmable PLL synthesised clock generator (50 to 800MHz) in 32-pin LQFP packages; the NBC12439FN 3.3/5V programmable PLL synthesised clock generator (50 to 800MHz) in a 32-pin LQFP package with a power-down input in the 28-pin PLCC package; and the NBC12439FA, a 3.3/5V programmable PLL synthesised clock generator (50 to 800MHz) in a 32-pin LQFP package with a power down input in the 32-pin LQFP package.

The NBC12429FN is offered in a 28-pin PLCC and priced at $4.85 per unit in 10,000 unit quantities.

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