Integrated RF synthesizers with embedded VCOs

ST’s synthesizers are the only single-chip devices with available output frequency above 3.0 GHz. The introduction of the STW81101 and STW81102 meets the increasing demand of equipment manufacturers for space and cost-efficient solutions in radio applications from cellular base stations to satellite communications and CATV equipment.



Frequency synthesizers form the basis of most radio designs and their performance largely affects the operation of the overall system. The leading requirements for signal-generating components in today’s communications equipment include minimized phase noise and broadband frequency coverage.



Targeted at a wide range of radio-transceiver applications from cellular network infrastructure to point-to-point radio, cable TV and satellite systems, ST’s STW81101 and STW81102 exhibit the industry’s best integrated phase-noise performance for single-chip RF Integer’N synthesizers. The measured values are 0.2° RMS (Root Mean Square) at 1 GHz, 0.5° RMS at 2 GHz, and 1.3° RMS at 4 GHz with a frequency step of 200 kHz. Outstanding suppression of random frequency fluctuations in a signal provides more design margin and the low phase noise also satisfies the stringent requirements of system manufacturers for minimized bit-error rates in voice and data transmission.



ST’s new RF synthesizers provide multi-band capabilities and unparalleled frequency coverage. The combination of embedded VCOs (voltage-controlled oscillators) with automatic center-frequency calibration and multiple output options allows the devices to operate in multiple bands, over an extremely wide spectrum from 750 MHz up to 4.65 GHz. Instead of using a dedicated device for each frequency range, equipment suppliers can now fit any multi-band radio application, such as a quad-band base station transceiver, with a single ST synthesizer. Moreover, the STW81101 and STW81102 are currently the only single-chip synthesizers in the market for applications operating in 3 GHz and 4 GHz bands, such as WiFi and WiMAX base stations or Fixed Wireless Radio Links.



Versatility of the STW8110x product family is further enhanced by the dual digital interface, with the I²C protocol for connecting multiple devices, complemented with the fast, Serial to Parallel Interface (SPI) bus.



Manufactured in the Company’s proprietary world-class BiCMOS SiGe technology, ST’s single-chip RF synthesizers surpass competing solutions in performance and reliability, while reducing the bill-of-materials and footprint by up to 60% compared with a traditional discrete approach.



Pin-to-pin compatible with its predecessor (STW81100), the STW81101 and STW81102 synthesizers are supplied in QFN-28 lead-free packages. The evaluation kits include an evaluation board, the STWPLLSim software for PLL filter design and noise simulation, the programming GUI (Graphical User Interface), and the guidelines for application board design.



The new STWPLLSim is a powerful and user-friendly interactive tool enabling very fast and accurate PLL design and optimization of the STW8110x devices, starting from high-level parameters such as the loop bandwidth and the phase margin. The accuracy of the noise modeling ensures successful first–loop-filter design in a course of minutes, compared to the lengthy design cycles required by traditional hand optimization.



Evaluation kits and production devices will be available soon. The STW81101 and STW81102 will be sold at a price of $3 in volume.