TI LMX2571低功耗宽带RF频率合成器解决方案

TI公司的LMX2571是低功耗宽带PLLatinum™ RF频率合成器,集成了Delta-Sigma分数N PLL,多核压控振荡器(VCO),可编输出分压器和两个输出缓冲器.VCO核频率高达5.376MHz,连续输出频率10 MHz 到1344 MHz,主要用在双向无线电,陆基雷达,点对点微波通信,SDR,矢量信号分析仪,无线通信测试仪,无线中继器,TETRA基站等.本文介绍了LMX2571主要特性,框图,几种典型应用电路,以及LMX2571EVM评估板(EVM)主要特性,电路图,材料清单和PCB设计图.
The LMX2571 is a low-power, high-performance, wideband PLLatinum™ RF synthesizer that integrates a delta-sigma fractional N PLL, multiple core voltage-controlled oscillator (VCO), programmable output dividers and two output buffers. The VCO cores work up to 5.376 GHz resulting in continuous output frequency range of 10 MHz to 1344 MHz.
This synthesizer can also be used with an external VCO. To that end, a dedicated 5-V charge pump and an output divider are available for this configuration.A unique programmable multiplier is also incorporated to help improve spurs, allowing the system to use every channel even if it falls on an integer boundary.
The output has an integrated SPDT switch that can be used as a transmit/receive switch in FDD radio application. Both outputs can also be turned on to provide 2 outputs at the same time.
The LMX2571 supports direct digital FSK modulation through programming or pins. Discrete level FSK, pulse shaping FSK, and analog FM modulation are supported.
A new FastLock technique can be used allowing the user to step from one frequency to the next in less then 1.5 ms even when an external VCO is used with a narrow band loop filter.
LMX2571主要特性:

Any Frequency from 10 MHz to 1344 MHz
Low Phase Noise and Spurs
–123 dBc/Hz at 12.5 kHz Offset @ 480 MHz
–145 dBc/Hz at 1 MHz Offset @ 480 MHz
Normalized PLL Noise Floor of –231 dBc/Hz
Spurious Better Than –75 dBc/Hz
New FastLock to Reduce Lock Time
A Novel Technique to Remove Integer Boundary Spurs
Integrated 5-V Charge Pump...