原标题：NS LMH2120 6GHz线性RMS功率检测方案

　　NS 公司的LMH2120是6GHz线性RMS功率检测器，动态范围40dB，工作频率从50 MHz到6 GHz，一致性优于±0.5 dB，对温度不敏感，工作电压2.7V-5.0V,主要用在多模式多频段功率控制如GSM/EDGE，CDMA /CDMA2000，WCDMA，OFDMA和LTE，基础设备的RF功率控制。本文介绍了LMH2120主要特性，方框图，发送功率控制系统框图，应用电路以及LMH2120 评估板电路图和LMH2120 评估板材清单。

　　6 GHz Linear RMS Power Detector with 40 dB Dynamic

　　The LMH2120 is a 40 dB Linear RMS power detector particularly suited for accurate power measurement of modulated RF signals that exhibit large peak-to-average ratios, i.e, large variations of the signal envelope. Such signals are encountered in W-CDMA and LTE cell phones. The RMS measurement topology inherently ensures a modulation insensitive measurement.

　　The device has an RF frequency range from 50 MHz to 6 GHz. It provides an accurate, temperature and supply insensitive, output voltage that relates linearly to the RF input power in volt. The LMH2120’s excellent conformance to a linear response enables an easy integration by using slope and intercept only, reducing calibration effort significantly. The device operates with a single supply from 2.7V to 5V. The LMH2120 has an RF power detection range from -35 dBm to 5 dBm and is ideally suited for use in combination with a directional coupler. Alternatively, a resistive divider can be used.

　　The device is active for EN = High, otherwise it is in a low power consumption shutdown mode. To save power and prevent discharge of an external filter capacitance, the output (OUT) is high impedance during shutdown. The LMH2120 power detector is offered in a tiny 6-bump micro SMD package.

　　LMH2120主要特性：

　　■ Linear root mean square response

　　■ 40 dB linear-in-V power detection range

　　■ Multi-band operation from 50 MHz to 6 GHz

　　■ Lin conformance better than ±0.5 dB

　　■ Highly temperature insensitive

　　■ Modulation independent response

　　■ Minimal Slope and Intercept variation

　　■ Shutdown functionality

　　■ Wide supply range from 2.7V to 5V

　　■ Tiny 6-bump micro SMD package

　　LMH2120应用：

　　■ Multi Mode, Multi band RF power control

　　— GSM/EDGE

　　— CDMA/CDMA2000

　　— W-CDMA

　　— OFDMA

　　— LTE

　　■ Infrastructure RF Power Control

　　图1。LMH2120方框图

　　图2。LMH2120发送功率控制系统框图

　　图3。LMH2120降低剩余波纹的低通滤波器

　　图4。LMH2120电阻分压器应用框图

　　LMH2120 评估板

　　图5。LMH2120 评估板外形图

　　图6。LMH2120 评估板电路图

　　LMH2120 评估板材清单：

　　图7。LMH2120 评估板测量框图