A compact 5.6 GHz low noise amplifier with new on-chip gain controllable active balun

A dual gain low noise amplifier for a 5.6 GHz ISM band direct conversion receiver, has been designed using a TSMC 0.25 μm CMOS process and features a gain controllable on-chip active balun. The LNA provides gains of 19.5 dB and 12 dB in the two modes with 50% power savings in the low gain mode, while a noise figure of 3.1 dB and an IIP3 of -11.5 dBm have been achieved. A simple and novel gain control technique has been adopted and the gain control circuitry has been integrated with the balun.