GPS has become a standard feature in a wide range of consumer products, from personal navigation devices to digital video cameras, watches, electric cars, and more. GPS signal power levels are weak and below the noise floor at -155 dBm. In many of these products, especially smart phones, strong transmitters such as Bluetooth, WLAN and cellular can drive the GPS LNA into compression. When the GPS LNA is in compression, it has lower gain which causes poor GPS reception; it also generates intermodulation products and harmonics from the transmitter signals, capable of overpowering weak signals and leading to loss of GPS reception.

GPS Low Noise Amplifiers to suppress Cellular and WLAN InterferenceNXP Semiconductors SiGe:C low noise amplifiers (LNAs) are designed to improve the linearity, noise figure and reception of GPS signals, including GloNass and Galileo, while offering the smallest footprint in the market. As the industry’s first GPS LNAs to dynamically suppress strong cellular, Bluetooth and WLAN transmit signals, the NXP BGU700x family offers the best reception for weak GPS signals, delivering an improvement of 10 dB or better IP3 under -40 to -20 dBm jamming conditions, while the noise figure remains below 1 dB. Requiring only two external components, the BGU700x LNAs save up to 50 percent in PCB size and 10 percent in component cost.

The NXP BGU700x/BGU8007 series use adaptive biasing to immediately detect any output power from jammers, and compensate by temporarily increasing the current. As a result, optimal GPS signal reception is maintained for as long as possible. Each device in the BGU700x/BGU8007 series requires only one input matching inductor and one supply decoupling capacitor to complete the design. This creates a very compact design and lowers the bill of materials. For example, the BGU7005 is in a 1.45-mm x 1-mm package with smaller application area. Available in extremely small 6-pin packages, the new LNAs reduce footprint, lower cost, and enhance reception in systems that use an active or patch antenna.