Oscillators Replace Crystal with Silicon
Thu, 10/09/2008 - 6:03am
Silicon Laboratories’ Si500 family of quartz-free, all silicon oscillators enable replacement of quartz-based XOs with an IC solution. The devices significantly expand Silicon Labs' product offering to address <100 MHz XO market and offer a selection of differential and single-ended clock formats, 1.5 ps rms phase jitter, 2 ps rms maximum period jitter and core power of 8 mA. The devices support differential clock outputs, such as LVPECL, LVDS and HCSL, in addition to CMOS and SSTL formats. The Si500 family supports a dual-output CMOS format mode in which a single device can produce two output clocks at the same frequency, eliminating the need for external clock buffers. The products act as a clock source for serial links, including SATA, PCI Express and USB.
Replacing crystal with silicon cuts lead times from up to 12 weeks down to two weeks. The components eliminate the quartz resonator that must be cut and tuned for each frequency, and replaces it with a silicon oscillator manufactured using standard, high-volume IC manufacturing processes capable of generating any output frequency from 0.9 to 200 MHz. The oscillators demonstrate operating voltages of 1.8, 2.5 and 3.3 V, and an operating temperature range from 0°C to 70°C.
The product family supports frequency stability options ranging from ?100 to ?150 ppm, providing customers with drop-in compatibility with quartz-based oscillators. The components are suitable in digital still cameras, camcorders, printers, PC peripherals, LCD displays, enterprise switches and routers, servers and workstations, white goods and storage applications using Hard Disk Drives (HDDs). The family comes with an OE pin yielding driver stopped, tristate and power down options.
The oscillators exhibit immunity to the contamination issues that affect traditional hermetically-sealed ceramic or metal-packaged XOs during device assembly. Using mixed-signal analog circuitry, the components are compensated for frequency variation due to operating temperature range, initial frequency accuracy, supply voltage change and output load change. The Si500 family provides temperature stability on par with crystal oscillators. The devices have no moving parts and are highly immune to shock and vibration. They are available in either a four-pad or six-pad, 3.2 × 4 mm dual flat no-lead (DFN) package with footprint compatibility with a 3.2 × 5 mm layout. The family uses DSPLL® technology to eliminate the need for resonator fabrication and tuning since there are no moving parts.