Microwave Engineering Europe - March 2009 - (Page 31) PRODUCTS 31 Simplified clock generator architecture reduces cycle time and complexity in networking and communications systems Analog Devices has introduced a clock generator that simplifies clock design and reduces the need for oscillators in multistandard networking and communications infrastructure systems, designated AD9551. The clock generator features a new, simplified architecture engineered by the company that can generate and translate multiple precision network clock frequencies, which enables the replacement of as many as five oscillators. Oscillators support forward error correction (FEC), holdover, switchover, and precise frequency generation — functions that are essential in network switches, routers, and line cards. In addition to saving board space, the AD9551 provides more accurate and reliable performance than discrete oscillators, while reducing system development time and complexity by making it easier for networks relying on incompatible standards to share and transfer data. The clock generator accepts one or two reference input signals and generates one or two output signals that are harmonically related by a programmable factor of 1 to 63. Precisely translating the reference frequency to the desired output frequency, it includes input receivers and output drivers that are capable of either single-ended or differential operation. Onchip reference monitoring and switchover circuitry internally synchronise the two references to prevent phase perturbations at the output in the event of a reference failure. Should either or both references fail, the AD9551 maintains a steady output signal with no phase disturbance on the output. The device relies on an external 26-MHz crystal (nominal) and the internal digitallycompensated crystal oscillator (DCXO) of the first of two cascaded fractional-N phaselocked loops (PLLs) to provide a clean reference for the second PLL, and to hold the output frequency in case of reference failure. The second fractionalN PLL enables fine precision output frequency tuning with low phase noise. The AD9551 provides a serial-peripheral interface (SPI) port, and pin-selectable preset divider values that offer an assortment of frequency ratios, including all the standard rates for Gigabit Ethernet (644.53125 MHz), 10 Gigabit Ethernet (625 MHz), SONET/SDH (622.08 MHz), and Fiberchannel (657.421875 MHz) as well as the established FEC ratios (15/14, 239/237, 239/238, 255/237, 255/238). www.mwee.com/214502714 WCDMA power amplifiers with integrated directional couplers Skyworks Solutions has introduced a family of single and dual-band WCDMA power amplifiers (PA) for universal mobile telecommunications system (UMTS) applications that integrate the directional coupler, significantly reducing the phone board footprint and bill-of-material costs. The company’s expanded portfolio of front-end solutions now claims five of the world’s smallest and highest performance UMTS PAs that support Bands I, II, IV, V and VIII, and two dual band PAs that support the most popular band combinations — bands I/VIII and II/V. These compact solutions provide seamless operation and offer high power added efficiency (PAE) at mid and low powers, significantly increasing talk times. The company’s Intera™ portfolio WCDMA power amplifiers now includes the: • SKY77186 for Band I: 1920 to 1980 MHz; • SKY77187 for Band II: 1850 to 1910 MHz; • SKY77188 for Band V, VI: 824 to 849 MHz; • SKY77189 for Band VIII: 880 to 915 MHz; and • SKY77191 for Band IV, IX, X: 1710 to 1785 MHz. The five small and efficient 3- x 3-mm solutions are fully matched, 10-pad surface mount modules. Because of high efficiencies attained throughout the entire power range, the devices deliver unsurpassed talk-time advantages. They also meet stringent spectral linearity requirements of high-speed downlink packet access (HSDPA) data transmission with high PAE. The two 4 x 5 mm dual band PA modules are the SKY77195 for Bands I and VIII, covering 1920 to 1980 MHz and 880 to 915 MHz; and the SKY77196 for Bands II and V covering 1850 to 1910 MHz and 824 to 849 MHz. Revolutionary integration techniques pack most of the external passive components into the modules, requiring only two external bypassing capacitors for the two bands compared to 10 to 14 passives typically required with two single band PA modules. This results in significant BOM savings as well as up to 40 to 50 percent board area savings. The single GaAs MMIC contains all active circuitry in the module. For example, it contains on-board bias circuitry, as well as input and interstage matching circuits. Output match into a 50-ohm load is realized off-chip within the module package to optimize efficiency and power performance. www.mwee.com/214501778 ● Microwave Engineering Europe ● March 2009 www.mwee.com http://www.mwee.com/214502714 http://www.mwee.com/214501778 http://www.mwee.com
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.