原创 高增益GPS方案

  Avago公司的ALM-1612是高增益低噪音 1.575GHz GPS放大器,集成了低噪音放大器(LNA)和GPS FBAR滤波器,具有可变电流/关断功能. ALM-1612采用GaAs pHEMT工艺制造,具有非常低的噪音,典型值为0.95dB, 典型增益为18.2dB, IIP3 = +2 dBm, IP1dB = -8 dBm,可用于GPS前端接收模块.

       本文介绍了ALM-1612的主要特性和指标, 应用电路, 演示板和演示板所用元件表以及散射参数和测量参考平面.

       1.575GHz GPS High-Gain Low Noise Amplifier with Integrated Filter and Variable Current/Shutdown Function
       Avago Technologies’ ALM-1612 is a GPS front-end module that combines a low-noise amplifier (LNA) with a GPS FBAR filter. The LNA uses Avago Technologies’ proprietary GaAs Enhancement-mode pHEMT process to achieve high gain with very low noise figure and high linearity. Noise figure distribution is very tightly controlled. A CMOS-compati¬ble shutdown pin is included either for turning the LNA on/off, or for current adjustment. The integrated filter utilizes an Avago Technologies’ leading-edge FBAR filter for exceptional rejection at Cell/PCS-Band frequencies.
       The low noise figure and high gain, coupled with low current consumption make it suitable for use in critical low-power GPS applications or during low-battery situations.

       ALM-1612主要特性:
       Very Low Noise Figure: 0.95 dB typ.
       High Gain: 18.2 dB typ.
       High IIP3 and IP1dB
       Exceptional Cell/PCS-Band rejection
       Advanced GaAs E-pHEMT & FBAR Technology
       Low external component count
       Shutdown current: < 5 uA
       CMOS compatible shutdown pin (SD) current @ 2.7 V: 0.1mA
       ESD: For RFin (Pin 3): ESD Human Body Model > 3kV; All other pins: ESD Machine Model = 70V, ESD Human Body Model = 350V
       Meets MSL3
       Useable down to 1.8V supply
       Adjustable current via single external resistor/voltage
       Small package dimension: 3.3(L)x2.1(W)x1(H) mm3
       ALM-1612主要指标(25度C典型性能)
       At 1.575GHz, Vdd = 2.7V, Idd = 6.0mA
       Gain = 18.2 dB
       NF = 0.95 dB
       IIP3 = +2 dBm, IP1dB = -8 dBm
       S11 = -9 dB, S22 = -14 dB
       Cell-Band Rejection: 69 dBc
       PCS-Band Rejection: 67 dBc

       应用:
       GPS Receiver Front-end Module
 

图1.ALM-1612应用电路



图2.ALM-1612演示板

ALM-1612演示板所用元件表





图3. ALM-1612应用电路图

图4.ALM-1612散射参数和测量参考平面