Avago公司的ALM-1412具备非常低的噪声指数和高线性度，可以大幅度改善GPS接收器的灵敏度，这款FBAR滤波器在Cell/PCS移动通信频带提供了相当优异的拒斥能力，使它成为改善手机中同步GPS(S-GPS)接收器性能的理想器件。本文介绍了ALM-1412的主要性能和指标，内部电路图，Rx 前端简化方框图以及ALM-1412应用电路图，演示板和应用材料清单。

ALM-1412
1.575 GHz  GPS LNA with Integrated Filter and Variable Current/Shutdown Function

Avago Technologies’ ALM-1412 is an LNA module, with integrated filter, designed for GPS band applications at 1.575GHz. 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-compatible 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 ALM-1412 is useable down to 1 V operation. It achieves low noise figure, high gain and linearity even at 1 V, making it suitable for use in critical low-power GPS applications or during low-battery situations.



主要特性：
Very Low Noise Figure: 0.77 dB typical
High Gain: 13.1 dB typical
High IIP3 and IP1dB
Exceptional Cell/PCS-Band rejection
Advanced GaAs E-pHEMT Technology
Low external component count
Wide Supply Voltage: 1 V to 3.6 V
Shutdown current: < 0.1 μA
CMOS compatible shutdown pin (SD) current @ 2.8 V: 0.1 mA
Adjustable current via single external resistor/voltage
Meets MSL3 and Lead-Free
ESD-protected RF input: 3 kV HBM
Small package dimension: 3.3(L)x2.1(W)x1.1(H) mm3
Specifications (Typical Performance at 25°C)
At 1.575 GHz, Vdd = 2.85 V, Idd = 9.0 mA
Gain = 13.1 dB
NF = 0.77 dB
IIP3 = +7.0 dBm, IP1dB = +3.4 dBm
S11 = -9 dB, S22 = -10 dB
Cell-Band Rejection: 61 dBc
PCS-Band Rejection: 54 dBc
At 1.575 GHz, 1.0 V supply
S21 = 9.4 dB
NF = 1.2 dB
Idd = 2.8 mA
应用：
GPS Band LNA




图1。ALM-1412简化内部电路图



图2。Rx 前端简化方框图



图3。ALM-1412应用电路图

下表为应用电路图材料清单：





图4。演示板和应用电路方框图

来源：中电网