News | June 15, 2009

Clock IC First To Harness GPS Signals For Synchronization

ADI's AD9548 taps ubiquitous GPS signals as a timing base; replaces multi-chip clocks with an accurate, highly integrated alternative for cable, optical networks and wireless base stations.

Analog Devices, Inc. (ADI), a global leader in high-performance signal processing, introduced recently the industry's first clock IC that enables system designers to use the standard, readily available and free 1-pps (pulse-per-second) signal of GPS (global positioning system) satellite transmitters to generate and synchronize clock signals for communications infrastructure equipment.

Developed for remote optical and wireless network nodes, cable infrastructure and data communications equipment, the AD9548 clock generator/synchronizer eliminates the dedicated oscillators, phase-locked loops, and other clock recovery circuitry communications systems previously required to generate clock signals synchronized to the widely available 1-pps GPS standard. Using the AD9548 to leverage GPS signals simplifies and shortens the design process while providing a lower-power timing reference.

The AD9548 includes a digital PLL that up-converts the 1-pps GPS signal while reducing input-time jitter or phase noise associated with the external references to as little as 300 femto seconds. The clock distribution section provides four output drivers. Each driver is programmable either as a single differential LVPECL/LVDS (low-voltage positive emitter-coupled logic/low-voltage differential signaling) output or as pairs of single-ended CMOS (complementary metal-oxide semiconductor) outputs. Each of the four outputs has a dedicated 30-bit programmable post divider enabling the generation of multiple different output frequencies. An integrated reference clock multiplier allows for system clock references as low as 4 MHz while still supporting outputs of up to 450 MHz. The AD9548 also includes a digitally-controlled loop filter programmable to as low as 1-MHz (1x10-3), as well as manual and automatic holdover circuitry that continuously generates a low jitter, valid output clock even when some, or all, references have failed.

Complementary components include ADI clock buffers, including the ADCLK854 LVDS/CMOS and ADCLK846 LVDS clock buffers, as well as the ADCLK954 and ADCLK946. The recently announced AD9356 and AD9357 transceivers also work well with the AD9548.

For more information, visit http://www.analog.com/pr/AD9548. For product information on ADI's additional clock and timing offerings, visit http://www.analog.com/en/clock-and-timing/products/index.html.

About Analog Devices
Innovation, performance, and excellence are the cultural pillars on which Analog Devices has built one of the longest standing, highest growth companies within the technology sector. Acknowledged industry-wide as the world leader in data-conversion and signal-conditioning technologies, Analog Devices serves over 60,000 customers, representing virtually all types of electronic equipment. Celebrating over 40 years as a leading global manufacturer of high-performance integrated circuits for analog- and digital-signal processing applications, Analog Devices is headquartered in Norwood, Massachusetts, with design and manufacturing facilities throughout the world. Analog Devices' common stock is listed on the New York Stock Exchange under the ticker "ADI" and is included in the S&P 500 Index. http://www.analog.com

SOURCE: Analog Devices, Inc.