Multi-stage variable gain LNAs focuses on wireless base station performance benefits

June 19, 2012 // By Paul Buckley
NXP Semiconductors N.V. has introduced the BGU706x series of multi-stage base station LNAs with variable gain featuring the industry’s lowest noise figure of 0.9 dB for a receive chain in silicon.

The architecture of the LNA is based on the integration of a very low-noise LNA with a bypass function followed by an analog-controlled variable gain amplifier (VGA). These BGU706x low-noise amplifiers deliver high linearity, while saving up to 80 percent in component count.

With a high RF input overdrive of 10-15 dBm, the BGU706x base-station LNAs provide exceptional ruggedness, and make use of  NXP’s silicon germanium carbon (SiGe:C) BiCMOS process technology for outstanding performance in high-frequency applications.

The BGU706x integrated multi-stage LNAs with variable gain claims to feature the industry’s lowest noise figure of 0.9 dB for a receive chain in silicon, enabling larger cell coverage.

The BGU706x LNAs claim to offer exceptional ruggedness, with high RF input overdrive of 10-15 dBm. This supports overall system stability and results in strong performance when the system part of the PA power is leaked into the LNA – a potential risk in time-duplexing systems.

The device’s analog gain control of 35 dB and high linearity input IP3 (0.9 dBm at max gain) makes the BGU706x series ideal for small cell sizes with demanding blocking requirements.

NXP’s integrated approach reducesthe overall LNA footprint and bill of materials (BoM), reducing component count by 80 percent – from 360 to 40 components in a typical implementation with a 6-channel receiver serving three sectors and 2Rx diversity.

The BGU706x LNAs optimize total system current consumption, using approximately 30-percent less power compared to solutions from other vendors. With less heat dissipation, the LNAs avoid jeopardizing NF and reliability, ultimately enabling longer lifetimes.

The new integrated BGU706x devices complement NXP’s existing BGU705x family. With RF input power overdrive of 20 dBm and high ESD protection (HBM 4 kV; CDM 2 kV), the devices are rugged and address demanding power requirements, delivering high maximum power gain of 37.5 dB in conjunction with low power consumption (65 – 90 mA).


The BGU7063 and the BGU705x series LNAs are available