What Is the Best LNA for Your GPS Receiver?
The Global Positioning System (GPS) has become
an integral part of our modern world, providing precise navigation
information for applications such as cellular, automotive, military,
surveying, and wearable electronics.
The table below highlights the measured evaluation board performance with the L1 to L5 tune.
Here are the main takeaways:
NF: Note that the extremely low NF values of 0.38 to 0.39 dB include the small losses (roughly 0.05 dB) associated with the evaluation board input SMA connector. De-embedded NF values are thus in the 0.34 dB range, making this the industry’s lowest NF solution for this band.
Gain: The gain values in the 20 to 22.5 range combine with the ultra-low NF to enable GPS receivers with the absolute lowest possible cascaded NF. Furthermore, the application schematic and matching values were also chosen to ensure unconditional stability.
Biasing: Biasing for most of Guerrilla RF’s pHEMT devices is extremely flexible, and GRF2071 / 2071W are no exception. Vdd can range from 2.7 to 5.0 volts with essentially no change to the device gain or NF. The device quiescent current (Iddq) can be adjusted over a typical range of 20 to 80 mA with only minimal NF degradation as the device current drops below 35 mA. Note that the device 1 dB compression point (P1dB) is more closely tied to Vdd than to Iddq, while just the opposite is true for the third-order intercept (IP3) performance.
Matching: The GRF2071 / 2071W matching performance shown in the VNA screen shot was achieved on the standard evaluation board with only nine external passive components. While care must be taken to ensure that the components on the LNA input are high-Q to optimize NF performance, the Guerrilla RF applications team achieves excellent results using low-cost GJM-series capacitors and LQG-series inductors from Murata with comparable substitutions posing no performance issues.
GRF2071 / 2071W are in full production using our
standard 2.0 x 2.0 mm DFN-6 plastic package. Tuned evaluation boards
and samples are available now.
For more information, contact your local Brennan Associates representative.