用于ADGM1304的评估板是一个双芯片、射频(RF)开关解决方案，内置单刀四掷(SP4T)、微型机电系统(MEMS)开关和控制芯片，均采用紧凑型5 mm × 4 mm LFCSP封装。SP4T开关采用ADI公司的MEMS开关技术，提供适合RF应用的最佳带宽、功耗处理能力和线性度性能。控制芯片可生成MEMS开关所需的高压信号，允许用户通过简单、灵活的互补金属氧化物半导体/低压晶体管对晶体管逻辑LVTTL兼容型并行接口控制其操作。

该评估板配有用于RF和控制信号的连接器以及链路，允许用户控制开关操作并评估其性能。

使用评估板时，有关操作信息请参阅ADGM1304数据手册。

The circuit shown in Figure 1 uses RF MEMS switches to route an RF signal between two surface-mount RF attenuators and two straight through paths.

Attenuating RF signals is commonly done in RF test instrumentation and receiver front ends to protect downstream circuitry and to increase dynamic range. Using discrete attenuators and switches maximizes design flexibility and routing options. In the Figure 1 circuit, two ADGM1304 single-pole, four-throw (SP4T) RF MEMS switches in a back to back configuration yield four independently switchable paths between input and output. Two of the paths are straight through transmission lines, the third path contains a 6 dB attenuator, and the forth path contains a 9 dB attenuator. Key to realizing this application is the use of ultralow insertion loss and highly linear switches to multiplex between the different path options.

The switches must be as transparent as possible to the RF signal and add as little insertion loss and distortion as possible. The ADGM1304 switches offer best in class insertion loss of 0.26 dB typical at 2.5 GHz, and a third-order intercept (IP3) performance of 69 dBm typical. In addition to insertion loss and distortion, another key benefit that the MEMS switch brings to this application is its ability to operate down to true dc. This means the switches do not limit lower frequency operation in a typical RF instrumentation attenuator switching application, and enables the instrument to pass dc bias voltages when required.

The physical size of the ADGM1304 device at 4 mm × 5 mm × 0.95 mm yields a significant reduction in printed circuit board (PCB) area compared to traditional electromechanical relays switching solutions. In addition, the actuation speed of the ADGM1304 switch is 30 μs, a significant improvement over electromechanical relays, which are in the order of milliseconds and introduce significant time lag in measurement systems. The actuation lifetime of the ADGM1304 device is guaranteed for one billion cycles, which is a major improvement over electromechanical relays and significantly increases overall system reliability.