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Oscillators Close to Phase-Noise Floor

Dec. 30, 2020
Miniature LVDS clock oscillators in the QTCC578 series are available with fixed output frequencies from 100 to 250 MHz and extremely low phase noise.

Low phase noise is important for many receiving systems and it usually starts with a system’s crystal oscillator. With a noise floor of -155 dBc/Hz, the QTCC578 series of quartz crystal oscillators from Q-Tech Corp. keep the noise low while occupying little space in aerospace, commercial, industrial, and military circuits and systems. They are supplied in hermetic ceramic housings measuring only 5 × 7 × 1.5 mm with gold-plated contact pads. Available for supply voltages of +2.5 and +3.3 VDC, the crystal oscillators provide low-voltage differential signal (LVDS) logic outputs at factory-programmable output frequencies from 100 to 250 MHz.

The QTCC578 series oscillators (see figure) are lead-free, RoHS compliant and EAR00 classified, available with screening to MIL-STD-55310 requirements for military applications. They can be specified for different operating temperature ranges, with frequency stability of ±25 ppm from -40 to +85°C and ±100 ppm from -55 to +125°C. The effects of ten years of aging are included in the stability specifications. The oscillators have 10-ms maximum start-up time with 600-ps rise/fall time and 0.2-ps maximum phase jitter.

Scott Sentz, Q-Tech’s director of sales and marketing explains: “This QTCC series answers the demand for low phase noise in a number of commercial applications like fiber channel, telecom, SONET, Ethernet/SynchE and microprocessor clock. This compact, reliable device is also effective in mil/aero applications, such as navigation, avionics and COTS.” The clock oscillators are available in tape-and-reel packaging for high-volume, automated-assembly applications. 

Q-Tech Corp., www.q-tech.com