原标题：TI LMX2592低噪音宽带RF锁相环(PLL)解决方案

　　TI公司的LMX2592是集成了VCO的低噪音宽带RF(20 MHz- 9.8 GHz)锁相环(PLL),支持分数N和整数N模式,6GHz输出的综合噪音49fs,输入频率高达1.4GHz,单电源3.3V工作,主要用在测试/测量设备,防卫和雷达(RADAR),微波骨干网,高速数据转换器的高性能时钟源和卫星通信.本文介绍了LMX2592主要特性,功能框图,应用电路以及评估板LMX2592EVM主要特性和测试建立电路,评估板电路图,材料清单和PCB设计图.

　　The LMX2592 is a low-noise, wideband RF PLL with integrated VCO that supports a frequency range from 20 MHz to 9.8 GHz. The device supports both fractional-N and integer-N modes, with a 32-bit fractional divider allowing fine frequency selection. Integrated noise of 49 fs for 6 GHz output makes it an ideal low noise source. Combining best-in-class PLL and integrated VCO noise with integrated LDOs, this device removes the need for multiple discrete devices in high performance systems.

　　The device accepts input frequencies up to 1.4 GHz, which combined with frequency dividers and programmable low noise multiplier allows flexible frequency planning. The additional programmable low noise multiplier lets users mitigate the impact of integer boundary spurs. In Fractional-N mode, the device can adjust the output phase by a 32-bit resolution. For applications that need fast frequency changes, the device supports a fast calibration option which takes less than 25 µs.

　　This performance is achieved by using single 3.3-V supply. It supports 2 flexible differential outputs that can be configured as single-ended outputs as well. Users can choose to program one output from the VCO (or doubler) and the second from the channel divider. When not being used, each output can be muted separately.

　　LMX2592主要特性:

　　Output Frequency Range from 20 to 9800 MHz

　　Industry Leading Phase Noise Performance

　　VCO Phase Noise: –134.5 dBc/Hz at 1-MHz Offset for 6 GHz Output

　　Normalized PLL Noise Floor: –231 dBc/Hz

　　Normalized PLL Flicker Noise: –126 dBc/Hz

　　49 fs RMS Jitter (12 kHz to 20 MHz) for 6 GHz Output

　　Input Clock Frequency up to 1400 MHz

　　Phase Detector Frequency up to 200 MHz, and up to 400 MHz in Integer-N Mode

　　Supports Fractional-N and Integer-N Modes

　　Dual Differential Outputs

　　Innovative Solution to Reduce Spurs

　　< 25-µs Fast Calibration Mode

　　Programmable Phase Adjustment

　　Programmable Charge Pump Current

　　Programmable Output Power Level

　　SPI or µWire (4-Wire Serial Interface)

　　Single Power Supply Operation: 3.3 V

　　LMX2592应用:

　　Test/Measurement Equipment

　　Defense and RADAR

　　Microwave Backhaul

　　High-Performance Clock Source for High-Speed Data Converters

　　Satellite Communications

　　图1.LMX2592功能框图

　　图2.LMX2592典型应用电路图

　　评估板LMX2592EVM

　　LMX2592EVM High Performance, WidebandPLLatinum™ RF Synthesizer Evaluation Board This Evaluation Module is for the LMX2592, which outputs very high frequency signals with industry leading phase noise. The integrated VCO allows minimal discrete external components to design. The PCB is optimized for performance as well as designed for easy customization of the loop filter. An LED is designed for quick visual check on the PLL lock status. With an on-board oscillator, setup process only requires a 3.3V power supply and an included USB2ANY module. The software is simple, with an intuitive and user friendly GUI.

　　评估板LMX2592EVM主要特性:

　　Very low phase noise output from 20 to 9800 MHz

　　Can lock to inputs signals from 5 to 1400 MHz

　　Single 3.3V power supply

　　Two differential outputs with programmable output power

　　This EVM has the complete circuit for the synthesizer, optimized and tested for performance, and includes a USB programming module

　　图3.评估板LMX2592EVM外形图

　　图4.评估板LMX2592EVM测试图

　　图5.评估板LMX2592EVM电路图

　　评估板LMX2592EVM材料清单:

　　图6.评估板LMX2592EVM PCB设计图(1)

　　图7.评估板LMX2592EVM PCB设计图(2)

　　图8.评估板LMX2592EVM PCB设计图(3)

　　图9.评估板LMX2592EVM PCB设计图(4)

　　图10.评估板LMX2592EVM PCB设计图(5)

　　图11.评估板LMX2592EVM PCB设计图(6)

　　图12.评估板LMX2592EVM PCB设计图(7)

　　图13.评估板LMX2592EVM PCB设计图(8)

　　图14.评估板LMX2592EVM PCB设计图(9)

　　图15.评估板LMX2592EVM PCB设计图(10)