Does anyone have some experience with using programmable (instead of fixed frequency) crystal oscillator ICs as the clock reference for Analog Device's PLLs?
I'm looking for a clock oscillator with a frequency that is a binary multiple of 10.7 MHz (e.g. 10.7 / 21.4 / 42.8 MHz) to use as the reference for a PLL, because I want to use the same oscillator also as a coherent 10.7 MHz source for some related IF circuitry.
It appears that fixed XCOs with 21.4MHz or 42.8MHz are not easily available as off the shelf components.
However, a number of manufacturers offer programmable clock oscillators that can be ordered preset to these frequencies.
For example, this Digikey part: XLH730021.400000X-ND
Is it advisable to use a configurable clock oscillator as the reference for a PLL?
Such configurable clock sources themselves are internally based on some sort of PLL circuit and therefore have a different (probably worse) phase noise and jitter than a conventional fixed frequency crystal oscillator, and they certainly have spurs.
I fear that the overall phase noise of my PLL circuit will suffer. I remember having had problems with a Fast Ethernet chip's internal frequency multiplier when clocking it from a programmable 25 MHz clock oscillator (but that was a long time ago, so the programmable clock oscillators might have improved in the meantime).
What is your experience on this?