Enhancement mode LNAs offer low noise figure and high linearity

August 01, 2012 // By Jean-Pierre Joosting
Skyworks has introduced two GaAs, pHEMT, enhancement mode, low noise amplifiers (LNAs) that offer low noise figure, high linearity, and excellent return loss while drawing very low bias current. The advanced GaAs pHEMT enhancement mode process provides better performance compared to SiGe LNAs.

The SKY67012-396LF (0.3 to 0.6 GHz) and SKY67013-396LF (0.6 to 1.5 GHz) LNAs are ideal for general purpose industrial, scientific, medical (ISM band), and other high frequency applications such as public safety and land mobile radios, security and radio frequency identification systems, cellular transceivers, and wireless sensors. On-die active bias design ensures consistent performance, enables unconditional stability, and simplifies external matching.

These highly flexible and low power gallium arsenide pHEMT LNAs have a highly efficient linear design, low noise figure and small form factor. At the same time, the very low current draw (5 mA) and wide input voltage range (1.8 to 5 V) capability provides manufacturers with an ideal low noise amplifier solution for battery-powered receivers and sensors.

The SKY67012-396LF offers the designer the ability to externally adjust supply current between 5 to 15 mA. Noise figure of 0.85 dB, gain of 16.5 dB, and 24 dBm OIP3 are achievable at 0.45 GHz with 3.3 V supply and 15 mA of bias current. The device can also be biased from 1.8 to 5 V and will still achieve an OIP3 of 18 dBm, and 15 dBm OP1dB with only 5 mA of bias current from 3.3 V supply. This LNA operates in the frequency range of 300 to 600 MHz and the associated evaluation board is optimized for operation in the 433 MHz ISM band.

For the SKY67013-396LF a noise figure of 0.85 dB, gain of 14.0dB, and 26 dBm OIP3 are achievable at 0.9 GHz with 3.3 V supply and 15 mA of bias current. The device can also be biased from 1.8 to 5 V and will still achieve a OIP3 of 22 dBm, and 15 dBm OP1dB with only 5 mA of bias current from 3.3 V supply. This LNA operates in the frequency range of 600 to 1500 MHz and the associated evaluation board is optimized for operation in the 866 and 915 MHz ISM