A low-voltage, low-power single-ended LNA is implemented in a 0.25µm SOI CMOS technology. A theoretical basis for the design is used to develop design constraints in conjunction with a layout-aware design flow providing early insight into parasitic effects. The SOI CMOS LNA has a post-layout simulated noise figure of less than 3 dB; input IP3 of −10 dBm and small-signal gain of 19.2 dB within the 3–5 GHz band. Total current consumption is 5.2 mA from 1.5 V supply voltage. The LNA can also operate under a 1V supply voltage with relatively small linear performance degradation. The chip area is 0.89 mm². Due to the high-resistivity silicon substrate, buried oxide isolation and low threshold voltage, the SOI CMOS technology offers significant performance improvements for LNAs, which makes the designed LNA well suitable for implantable WBANs.