Turn Down the Noise with LNAs
The urban world is full
of noise-generating electronics ranging from cell phones to WiFi routers. This fact is especially troubling for the telecommunications industry, which needs its own noisy devices to be heard amongst the crowd. To fight the ever-increasing noise floor, noise-mitigation devices like low-noise amplifiers (LNAs) are used to increase the signal-to-noise ratio (SNR) to levels that can be accepted by downstream receiver circuitry. Because every component within an electronic circuit produces noise, however, the design of LNAs requires critical analysis of each component in the LNA and receiver system. The parameters that are most useful to an LNA designer are power consumption, linearity, gain, noise figure (NF), stability, and transistor technology.
To maintain the greatest power efficiency for portable-radio designs, LNAs have to balance their gain, linearity, and NF performance with minimal power. For example, devices that have control inputs for the bias and supply inputs can control the quiescent current independently of the supply voltage. With such controls in hand, a designer is able to set the lowest voltage point for the bias and supply to achieve the necessary gain, linearity, and NF. Using a lower supply voltage also could increase the LNA’s resilience when faced with high power surges.
Full article by By Jean-Jacques DeLisle, Microwaves and RF
About the Author
Roger Chu is the Marketing Coordinator at GSAmart, the leading GSA sales and marketing partner for technology companies.
