A Single-Pin Antenna Interface RF Front End Using a Single-MOS DCO-PA and a Push–Pull LNA

Abstract

We propose a simple power-efficient sub-1-V fully integrated RF front end (RFE) for 2.4-GHz transceivers. It intro- duces the following innovations. First, a function-reuse single- MOS digitally controlled oscillator power amplifier (DCO-PA) with full supply utilization improves antenna-to-DCO isolation for better resilience to jammers. Second, a noninverting transmit- ter (TX) matching transformer with a zero-shifting capacitor sup- presses the second-harmonic emission of the DCO-PA and allows a single-pin antenna interface for both TX and receiver (RX) modes eliminating the transmit/receive (T/R) switches in the signal path. Third, a push–pull low-noise amplifier (LNA) reuses the TX matching transformer for passive gain boosting that reduces power consumption. Fabricated in 65-nm CMOS, the RFE occupies merely 0.17 mm 2. Through the functional merge of the oscillator and PA, it can transmit 0 dBm at RF, featuring 10.2% power efficiency when delivering the RF power as low as −10 dBm at a 0.3-V supply. Under a 0.5-V supply, the LNA shows 11-dB gain and 6.8-dB noise figure (NF) while consuming 174 µW.