A 2.4GHz low-power SAW-less receiver for SoC coexistence

A 2.4GHz receiver with +6dBm out-of-band IIP3 with only 2.4 mA current consumption is demonstrated. A transformer-based push-pull differential LNA is used to co-exist with large out-of-band blockers caused by the presence of other transceivers in the same chip/system. An RF current-mode approach with a baseband single-opamp second-order filtering is used to enhance the linearity of the receiver for a given DC current. A current reuse technique is used to minimize the battery current consumption. Using two active inductors the DC current of the LNA is shared with the 1st stage of the opamp in both quadrature baseband filters following the passive mixers. The receive chain has a noise-figure of 7.8 dB at 2.4GHz and an OOB IIP3 of 6 dBm. The chip was implemented in 28nm CMOS and has an active area of 0.4 mm2