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ST STW81103 RF频率合成器应用方案

2007-09-20 嵌入式在线收藏 | 打印

ST公司的集成了压控振荡器(VCO)的射频合成器STW81103是第一个输出频率高达5GHz的单片射频合成器, 满足了微波无线电应用领域的设备制造商对注重空间和成本效益的解决方案的需求。

目标应用包括无线网络基础设施、CATV系统、仪表和测试设备。ST的STW81103在单片射频合成器中相噪性能最为出色，在1.16GHz下，相噪达到0.27度RMS (均方根)；在2.33GHz下，达到0.6度RMS；在4.67GHz下，达到1.5度RMS，频率阶跃200kHz。对信号内的随机频率波动的出色抑制能力，为设计人员提供了更大的设计余量；更低的相位噪声则满足了系统制造商对最小化数据和语音传输中的位错误率的严格要求。

    概述:

       The STMicroelectronics STW81103 is an integrated RF synthesizer with voltage controlled
       oscillators (VCOs). Showing high performance, high integration, low power, and multi-band
       performances, STW81103 is a low cost one chip alternative to discrete PLL and VCOs solutions.

       STW81103 includes an Integer-N frequency synthesizer and two fully integrated VCOs featuring low phase noise performance and a noise floor of -155dBc/Hz. The combination of wide frequency range VCOs (thanks to centerfrequency calibration over 32 sub-bands) and multiple output options (direct output, divided by 2 or divided by 4) allows to cover the 625MHz-762.5MHz, the 1087.5MHz-1525MHz, the 2175MHz-3050MHz and the 4350MHz-5000MHz bands.

       The STW81103 is designed with STMicroelectronics advanced 0.35μm SiGe process.

       主要特性:
       ■ Integer-N frequency synthesizer
       ■ Dual differential integrated VCOs with automatic center frequency calibration:
       – Direct output:
       2500 - 3050 MHz
       4350 - 5000 MHz
       – Internal divider by 2:
       1250 - 1525 MHz
       2175 - 2500 MHz
       – Internal divider by 4:
       625 - 762.5 MHz
       1087.5 - 1250 MHz
       ■ Excellent integrated phase noise
       ■ Fast lock time: 150μs
       ■ Dual modulus programmable prescaler (16/17 or 19/20)
       ■ 2 programmable counters to achieve a feedback division ratio from 256 to 65551 (prescaler 16/17) and from 361 to 77836 (prescaler 19/20).
       ■ Programmable reference frequency divider (10 bits)
       ■ Phase frequency comparator and charge pump
       ■ Programmable charge pump current
       ■ Digital lock detector
       ■ Dual digital bus interface: SPI and I2C bus (fast mode) with 3 bit programmable address
(1100A2A1A0)
       ■ 3.3V power supply
       ■ Power down mode (HW and SW)
       ■ Small size exposed pad VFQFPN28 package 5mm x 5mm x 1.0mm
       ■ Process: BICMOS 0.35μm SiGe
       典型应用:
       ■ 2.5G and 3G Cellular infrastructure equipment
       ■ CATV equipment
       ■ Instrumentation and test equipment
       ■ Other wireless communication systems

图1为STW81103方框图.

图2为应用电路图.

STW8110x 评估板的主要性能

       This application note describes the evaluation board (EVB) and the graphical user interface
(GUI) of the STW81101, STW81102 and STW81103 multi-band RF frequency synthesizers
(with integrated VCOs).

       The STW8110x GUI software allows the STW81101, STW81102 and STW81103
synthesizers to be programmed via an I2C/SPI control interface.
Three evaluation boards are available depending on the output matching network optimal

       frequency range:

       ■ EVB1G (single output - 1 GHz - output divider by 4)
       ■ EVB2G (single output - 2 GHz - output divider by 2)
       ■ EVB4G (single output - 4 GHz - direct output)