浅谈基于ADL5354设计的高性能RF混频方案

　　要求高线性度和低噪声的混频器应用设计一直是个难题。现有的混频器解决方案常常需要巴伦和放大器等外部元件，增加了设计复杂性。新款ADL5353和ADL5354混频器可实现满足高动态范围和低噪声需求的设计。

　　单通道ADL5353 混频器和双通道ADL5354 混频器工作在2300 至2900MHz 频率范围，提供极高的集成度，内置射频巴伦、用于双通道本振频率应用的本振开关、本振驱动器和集成式中频放大器。巴伦的集成使射频信号可被单端驱动，集成式中频放大器可以提供必要的增益，因而无需外部增益级电路。ADL5353 和ADL5354 可提供的IP3 和噪声指数性能，因而可以实现优异的无杂散动态范围。这些混频器还能提供强干扰信号下出色的噪声指数性能。高的无杂散动态范围和阻塞器性能下的低噪声指数使得这些混频器可用于接收机在有大干扰信号情况下工作的场合。5V （标称值）的ADL5353 和ADL5354 也能在功耗敏感应用中的3.3V 电源电压下工作。

 　ADL5354是高度线性双平衡（RF和LO平衡）RF混频器，输入频率从2300 MHz 到2900MHz.平衡的无源混频器具有良好的LO-RF泄漏，优于-35dBm.IF频率范围从30MHz到450MHz,功率转换增益8dB,单边带（SSB）噪音10dB,输入IP3为25dBm,输入P1为11dBm,LO典型驱动为0dBm.工作电压3.3V-5.0V,主要用在蜂窝无线基站接收器，无线链接下变换器等。

　　The ADL5354 uses a highly linear, doubly balanced, passive　mixer core along with integrated RF and local oscillator （LO）balancing circuitry to allow single-ended operation. The　ADL5354 incorporates the RF baluns, allowing for optimal　performance over a 2300 MHz to 2900 MHz RF input frequency　range. The balanced passive mixer arrangement provides good　LO-to-RF leakage, typically better than −35 dBm, and excellent　intermodulation performance. The balanced mixer core also provides extremely high input linearity, allowing the device to be used in demanding cellular applications where in-band　blocking signals may otherwise result in the degradation of　dynamic performance.

　　The ADL5354 provides two switched LO paths that can be used in　TDD applications where it is desirable to ping-pong between　two local oscillators. LO current can be externally set using　a resistor to minimize dc current commensurate with the　desired level of performance. For low voltage applications,the ADL5354 is capable of operation at voltages down to 3.3 V　with substantially reduced current.

　　The ADL5354 is fabricated using a BiCMOS high performance IC　process. The device is available in a 6 mm × 6 mm, 36-lead　LFCSP and operates over a −40℃ to +85℃ temperature range.

　　ADL5354主要特性：

　　RF frequency range of 2300 MHz to 2900 MHz
　　IF frequency range of 30 MHz to 450 MHz
　　Power conversion gain: 8 dB
　　SSB noise figure of 10 dB
　　Input IP3 of 25 dBm
　　Input P1dB of 11 dBm
　　Typical LO drive of 0 dBm
　　Single-ended, 50 Ω RF and LO input ports
　　High isolation SPDT LO input switch
　　Single-supply operation: 3.3 V to 5 V
　　Exposed paddle, 6 mm × 6 mm, 36-lead LFCSP
　　ADL5354应用：
　　Cellular base station receivers
　　Transmit observation receivers
　　Radio link downconverters

 图1.ADL5354功能方框图

 图2.ADL5354典型应用电路图

图3.ADL5354评估板电路图

     ADL5354评估板元件配置表:

 

图4.ADL5354评估板顶层布局图