A 1.5‐V transformer‐based ultra‐wideband LNA chip design

In this article, a low‐noise amplifier (LNA) for ultra‐wideband (UWB) systems operating at 3–5 GHz frequency range is presented. The proposed LNA uses an on‐chip transformer to achieve the realization of a wideband input‐integrated matching to the antenna impedance, as well as the cascode amplifier with shunt peaking can provide a high power gain. The transformer‐based LNA fabricated in a TSMC 0.18‐μm CMOS process with 1.5 V supply voltage achieves a maximum power gain of 19.2 dB in addition to the minimum noise figure (NF) of 3.5 dB, an input return loss (S 11 ) smaller than −9.3 dB over the whole frequency range. This circuit also present an input‐referred third‐order intercept point (IIP3) of −11 dBm at 5 GHz and an input‐referred 1 dB compression point of −21 dBm at 5 GHz. The chip area including pads is only 0.8 mm 2 and power dissipation is 13.5 mW. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2649–2652, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24705