2.4-GHz single-ended input low-power low-voltage active front-end for ZigBee applications in 90 nm CMOS

A 2.4-GHz CMOS single ended-input differential-output front-end built with a common source low noise amplifier (CS-LNA) and a switched transconductor mixer (SW-MIX) is presented. The circuit is designed and optimized to work in a ZigBee receiver. Since this is a low power consumption standard, a single-ended LNA is preferred over a fully-differential topology because it leads to lower cost in area and power consumption. Also, moderate and weak inversions regions were selected for the operation of the principal transistors. The front-end prototype has been implemented in a 90 nm RF process and occupies a chip area of 0.74 mm² including on-chip inductors. Very competitive results are observed: a maximum conversion gain (CG) of 30 dB, a DSB noise figure of 7.5 dB, a maximum IIP3 of -12.8 dBm and IIP2 of 14.4 dBm while it consumes 4.7 mW from a 1.2 V supply.