原标题：ADI ADRF6720 3G-4G通信系统开发方案

　　ADI公司的ADRF6720-27是宽带正交解调器,包括高度线性宽带解调器,分数N锁相环(PLL)和四个低相位噪音的多核压控振荡器(VCO),本地(LO)频率从356.25 MHz到2855 MHz,RF输出频率从400MHz到3000MHz, 2140 MHz 的P1dB输出10.8dBm, IP3输出31.1dBm,噪音−159.5 dBm/Hz,边带抑制−40.8 dB,工作电压3.3V,主要用在2G/3G/4G/LTE宽带通信系统,微波点对点通信,卫星调制解调器,军用/航空仪表.本文介绍了ADRF6720-27主要特性,功能框图和基本应用电路,以及评估板ADRF6720-27-EVALZ主要特性,测试建立图,电路图和材料清单与PCB设计文件.

　　The ADRF6720-27 is a wideband quadrature modulator with an integrated synthesizer ideally suited for 3G and 4G communication systems. The ADRF6720-27 consists of a high linearity broadband modulator, an integrated fractional-N phase-locked loop (PLL), and four low phase noise multicore voltage controlled oscillators (VCOs). The ADRF6720-27 local oscillator (LO) signal can be generated internally via the on-chip integer-N and fractional-N synthesizers, or externally via a high frequency, low phase noise LO signal. The internal integrated synthesizer enables LO coverage from 356.25 MHz to 2855 MHz using the multicore VCOs. In the case of internal LO generation or external LO input, quadrature signals are generated with a divide by 2 phase splitter. When the ADRF6720-27 is operated with an external 1 × LO input, a polyphase filter generates the quadrature inputs to the mixer. The ADRF6720-27 offers digital programmability for carrier feedthrough optimization, sideband suppression, HD3/IP3 optimization, and high-side or low-side LO injection. The ADRF6720-27 is fabricated using an advanced silicon- germanium BiCMOS process. It is available in a 40-lead, RoHS-compliant, 6 mm × 6 mm LFCSP package with an exposed pad. Performance is specified over the −40℃ to +85℃ temperature range.

　　ADRF6720-27主要特性:

　　I/Q modulator with integrated fractional-N PLL

　　RF output frequency range: 400 MHz to 3000 MHz

　　Internal LO frequency range: 356.25 MHz to 2855 MHz

　　Output P1dB: 10.8 dBm at 2140 MHz

　　Output IP3: 31.1 dBm at 2140 MHz

　　Carrier feedthrough: −44.3 dBm at 2140 MHz

　　Sideband suppression: −40.8 dBc at 2140 MHz

　　Noise floor: −159.5 dBm/Hz at 2140 MHz

　　Baseband 1 dB modulation bandwidth: >1000 MHz

　　Baseband input bias level: 2.68 V

　　Power supply: 3.3 V/425 mA

　　Integrated RF tunable balun allowing single-ended RF output

　　Multicore integrated VCOs

　　HD3/IP3 optimization

　　Sideband suppression and carrier feedthrough optimization High-side/low-side LO injection Programmable via 3-wire serial port interface (SPI)

　　40-lead 6 mm × 6 mm LFCSP

　　ADRF6720-27应用:

　　2G/3G/4G/LTE broadband communication systems

　　Microwave point-to-point radios

　　Satellite modems

　　Military/aerospace Instrumentation

　　图1. ADRF6720-27功能框图

　　图2. ADRF6720-27运行基本连接图(回路滤波器20kHz)

　　评估板ADRF6720-27-EVALZ

　　The ADRF6720-27 is a wideband quadrature modulator with an integrated synthesizer ideally suited for 3G and 4G communication systems. The ADRF6720-27 consists of a high linearity broadband modulator, an integrated fractional-N phase-locked loop (PLL), and four low phase noise multicore voltage controlled oscillators (VCOs). The ADRF6720-27 local oscillator (LO) signal can be generated internally via the on-chip integer-N and fractional-N synthesizers, or externally via a high frequency, low phase noise LO signal. The internal integrated synthesizer enables LO coverage from 356.25 MHz to 2855 MHz using the multicore VCOs. In the case of internal LO generation or external LO input, quadrature signals are generated with a divide by 2 phase splitter. When the ADRF6720-27 is operated with an external 1 × LO input, a polyphase filter generates the quadrature inputs to the mixer.

　　The ADRF6720-27 offers digital programmability for carrier feedthrough optimization, sideband suppression, HD3/IP3 optimization, and high-side or low-side LO injection. The ADRF6720-27 is fabricated using an advanced silicon- germanium BiCMOS process. It is available in a 40-lead, RoHS- compliant, 6 mm × 6 mm LFCSP package with an exposed pad. The ADRF6720-27-EVALZ evaluation board provides all of the support circuitry required to operate the ADRF6720-27 in its various configurations, as well as the application software used to interface with the device. Full specifications on the ADRF6720-27 are available in the product data sheet, which should be consulted in conjunction with this user guide when using the evaluation board.

　　评估板ADRF6720-27-EVALZ主要特性:

　　Full featured evaluation board for the ADRF6720-27

　　On-board USB for SPI control

　　3.3 V operation

　　C# software interface for serial port control

　　图3. 评估板ADRF6720-27-EVALZ外形图:左:顶部;右:底部

　　图4. 评估板ADRF6720-27-EVALZ测试建立图

　　图5. 评估板ADRF6720-27-EVALZ电路图

　　图6. 评估板ADRF6720-27-EVALZ US接口电路图

　　评估板ADRF6720-27-EVALZ材料清单:

　　评估板ADRF6720-27-EVALZ材料清单(未按装部分):