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