LNA Boosts ISM Band Performance Without Penalty

In many industrial, scientific, and medical (ISM) band wireless applications, receiver sensitivity greatly limits the range and reliability of the radio link. One way to get greater sensitivity is to add more gain. But that works well only if the noise figure is good enough. The Maxim Integrated Products MAX2634 solves that problem for some applications. This low-noise amplifier (LNA) for the 315- and 433-MHz ISM bands improves receiver sensitivity and offers an ultra-low 1.25-dB noise figure. Made from silicon-germanium (SiGe) biCMOS, the device generally outperforms discrete gallium-arsenide (GaAs) transistors and other CMOS circuits.

The MAX2634 suits automotive remote keyless entry (RKE) and tire-pressure monitoring designs, but it’s also a good match for any ISM application. It consumes 2.5 mA of current with a 2.2- to 5.5-V supply, and it has a temperature range of –40°C to 125°C. Also, its logic-enabled shutdown mode reduces supply current to less than 1 µA and eliminates the two discrete transistors normally needed to implement a shutdown function. No dc blocking capacitors are needed, keeping the footprint for key fob designs minimal.

The package is tiny 2- by 2-mm, six-pin SC70. Prices start at $0.50 in 1000-unit quantities. An evaluation kit is available for $50.

Maxim Integrated Products

www.maxim-ic.com/MAX2634