Aging? What about the Aging? Will they spec 1 year and add that in the 100 PPM spec? What does it do 3 to 5 years down the road.
Short Term Stability?
457 femtosecond phase jitter. Yes but defined over what range? The range where the LC oscillator is optimum?
Achieves -140dBc/Hz phase noise; yes but at what offset frequency?
Yes but I have 1 more question to ask; if this is such a great technology then what happened to Mobius Microsystems? Why was it acquired by IDT earlier this year.
Yes, I've been following these guys since they published their work at the ISSCC 2007:
when they were still Mobius Microsystems.
If I remember correct, the paper mentions using an elaborate digital calibration with the
aid of an external reference clock to achieve sub-100ppm setting accuracy.
I agree with you. The title could be over-optimistic for the IDT3C02 CMOS oscillator. But this "all-silicon" oscillator could certainly beat the 100 ppm quartz crystal oscillators available in the market...isn't it?
The length change of silicon is 2ppm/Kelvin
Length change of Aluminium is 23ppm/K
Copper has 16ppm/K
Lets assume that the silicon length change overrides the length change of the metal (whatever is used) , a temperature change of 50 Kelvin causes an inductance change of 100ppm
Same for the capacitors, I guess.
I have no idea how they trim the circuit to compensate the +/-20% process spread of the capacitors. Laser trimming? I see no space for a fractional PLL.
I see IDT claim 73c/10K, which is ok, but not much below even Digikey Crystal Osc prices.
There are also 1mA Crystal Oscillators, so their claims of lower power is more 'average', rather than comparing leading edge, with leading edge.
I can see it has a place, replacing the very bottom spec'd crystals, but Ceramic resonators are more threatened here.
The wide supply range is impressive.
Missing from their data sheet, is the Base Freq, I see mentioned above as 3GHz.
Also missing is any breakout of the 100ppm components : no dF/dT, dF/dV, etc
Can anyone explain how this technology works? Any grad student can build LC oscillator that oscillates at hundres of MHz or few GHz (I know first hand, I had a few students who built that)...by neither L or C are predictable so you will get a value of oscillation frequency which will be 20% off or so...you can tune that in with C (using varactor) or less likely with L (using some switches to connect more L if needed)...but how do you maintain that tuning over life of the product, temp changes, VVD variations etc...any hint is appreciated...Kris
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